Final Exam

Question 1

The three basic catabolic pathways are:

Check All That Apply

A) aerobic respiration.
B) deamination.
C) polymerization.
D) anaerobic respiration.
E) fermentation.

Answer 1

A) aerobic respiration.
D) anaerobic respiration.
E) fermentation.

Explanation: The three basic catabolic pathways are aerobic respiration, anaerobic respiration, and fermentation. All three begin with glycolysis, and then proceed through different reactions based on the organism and the conditions.

Question 2

Epinephrine:

Multiple Choice

A) inhibits the activity of lymphocytes.
B) reverses constriction of airways.
C) is an antihistamine.
D) causes desensitization.

Answer 2

B) reverses constriction of airways.

Question 3

What type of bond is found between carbon and hydrogen in most biological molecules?

Multiple Choice

A) Hydrogen bond
B) Ionic bond
C) Covalent bond
D) Van der Waals force

Answer 3

C) Covalent bond

Explanation: Carbon and hydrogen form bonds by sharing electrons. Bonds that involve the sharing of electrons are covalent bonds.

Question 4

All atoms in an element have the same number of protons.

A) True
B) False

Answer 4

A) True

Explanation: All atoms of an element have the same number of protons and will exhibit the same chemical properties. The number of neutrons may vary if there are different isotopes of the element. The number of electrons can vary as well, creating ions of that same element.

Question 5

Select the number of phosphates present in a molecule of ATP.

Multiple Choice

A) 1
B) 2
C) 3
D) 4

Answer 5

C) 3

Explanation: ATP, or adenosine triphosphate, contains adenine, ribose sugar, and three phosphates.

Question 6

When an inhibitor mimics the substrate and occupies the active site of the enzyme, this is referred to as _________blank inhibition.

Multiple Choice

A) allosteric
B) reference
C) competitive
D) noncompetitive

Answer 6

C) competitive

Explanation: Enzyme activity can be modified in several ways. Competitive inhibition occurs when an inhibitor occupies the active site of the enzyme and prevents the actual substrate from accessing the active site. Noncompetitive inhibition occurs when an inhibitor binds to a regulatory site on the enzyme that is separate and distinct from the active site.

Question 7

During DNA replication, the _________blank strand is synthesized continuously while the _________blank strand is synthesized in a series of short fragments called Okazaki fragments.

Multiple Choice

A) 5’; 3’
B) leading; lagging
C) parallel; antiparallel
D) forward; backward

Answer 7

B) leading; lagging

Explanation: The leading strand is synthesized continuously in the 5’ to 3’ direction. Since DNA polymerase can only build DNA in the 5’ to 3’ direction, the lagging strand is synthesized in short fragments called Okazaki fragments which are later joined by DNA ligase.

Question 8

The protein in a conjugated enzyme is referred to as the _________blank whereas the combination of the protein and the nonprotein cofactor is known as the _________blank.

Multiple Choice

A) holoenzyme; apoenzyme
B) apoenzyme; holoenzyme
C) apoenzyme; competitive enzyme
D) holoenzyme; exoenzyme

Answer 8

B) apoenzyme; holoenzyme

Explanation: The protein part of a conjugated enzyme is referred to as the apoenzyme. The combination of the protein enzyme (apoenzyme) plus the nonprotein cofactor(s) is called the holoenzyme.

Question 9

Viruses are inactive macromolecules inside of a host cell.

A) True
B) False

Answer 9

B) False

Explanation: Viruses are merely inactive macromolecules outside of a host cell. However, inside of a host cell, they can take over the cellular machinery for replication.

Question 10

Choose the statement that describes the first stage of phagocytosis.

Multiple Choice

A) Phagocytes form pseudopodia at the site of inflammation in order to grab the invading microbe.
B) Phagocytes move with deliberation along a gradient of stimulatory products at the site of injury.
C) Phagocytes make their way to an inflammatory site by random chance.
D) Phagocytes release substances to attack the extracellular microbe.

Answer 10

B) Phagocytes move with deliberation along a gradient of stimulatory products at the site of injury.

Explanation: During phagocytosis, the first step is chemotaxis of the phagocyte along a gradient of stimulatory products towards the site of inflammation or injury. Once at the scene, the phagocytic cell recognizes PAMPs on its target microbe, and after contact, pseudopodia are formed to internalize the microbe in a phagosome.

Question 11

Please select those nutrients that are essential for growth, reproduction, and maintenance of a bacterial cell.

Check All That Apply

A) DNA
B) Carbon
C) Silver
D) Hydrogen
E) Oxygen
F) Phospholipids
G) Nitrogen
H) Phosphorus
I) Sulfur

Answer 11

B) Carbon
D) Hydrogen
E) Oxygen
G) Nitrogen
H) Phosphorus
I) Sulfur

Explanation: The essential nutrients of a bacterial cell include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (CHONPS). There are others, not included among the choices, such as potassium, sodium, calcium, magnesium, chloride, and iron. While DNA and phospholipids are essential macromolecules within the bacterial cell, they aren’t considered nutrients because bacteria don’t require a supply of these premade; they synthesize them as needed.

Question 12

The second and third lines of host defenses determine whether cells are self or nonself by examining cell surfaces for identifying molecular markers.

A) True
B) False

Answer 12

A) True

Explanation: The ability to recognize cells as self or nonself by the immune response is important in the protection of host cells while initiating an attack to clear invaders. Certain cellular components of the second and third lines of defense are able to do this by scanning for cellular markers.

Question 13

A specific segment of DNA that contains the necessary code to make a protein or RNA molecule is a:

Multiple Choice

A) chromosome.
B) Z band.
C) gene.
D) VNTR.

Answer 13

C) gene.

Explanation: A gene is a specific segment of DNA that contains the necessary code to make a protein or RNA molecule. A gene can also be defined as the fundamental unit of heredity responsible for a given trait of an organism.

Question 14

The property of some metabolic pathways that enables them to serve multiple functions in the breakdown, synthesis, and conversion of metabolites is known as:

Multiple Choice

A) anabolism.
B) catabolism.
C) parabolism.
D) amphibolism.

Answer 14

D) amphibolism.

Explanation: Catabolic and anabolic processes can be integrated at various points to improve efficiency. For example, the intermediate of a catabolic pathway may be used in an anabolic pathway. This ability of pathways to serve multiple functions in both catabolic and anabolic processes is known as amphibolism.

Question 15

Which of the following pairs is mismatched?

Multiple Choice

A) Hay fever - type IV hypersensitivity
B) Transfusion reaction - type II hypersensitivity
C) Serum sickness - type III hypersensitivity
D) Poison ivy dermatitis - type IV hypersensitivity
E) Food allergy - type I hypersensitivity

Answer 15

A) Hay fever - type IV hypersensitivity

Question 16

The term used to describe a gently curved bacterium is

Multiple Choice

A) spirochete.
B) vibrio.
C) coccobacillus.
D) streptobacillus.

Answer 16

B) vibrio.

Explanation: Vibrio is the term used to describe bacteria that are shaped like a comma, or a gently curved bacterium.

Question 17

Select the major cellular targets of physical and chemical control agents.

Check All That Apply

A) Cell wall
B) Flagella
C) Cell membrane
D) Proteins
E) Microcompartments

Answer 17

A) Cell wall
C) Cell membrane
D) Proteins

Explanation: There are four main targets of physical and chemical control agents. These include the cell wall, the cell membrane, cellular synthetic processes, and proteins.

Question 18

A permanent change in the DNA base sequence is a:

Multiple Choice

A) primer.
B) catalyst.
C) mutation.
D) methylation.

Answer 18

C) mutation.

Explanation: A permanent change in the base sequence of DNA is a mutation. This may be an addition or deletion or substitution of the bases.

Question 19

You are preparing a solution by mixing 10 grams of glucose into distilled water. In this solution, distilled water is the:

Multiple Choice

A) solvent.
B) ion.
C) precipitate.
D) solute.

Answer 19

A) solvent.

Explanation: In this solution, water is the dissolving medium or solvent. Glucose is the solute. Water is the most common solvent in biological systems.

Question 20

_________blank are substances that provoke a specific immune response which is so discriminating that only a single molecular fragment, called a/an _________blank, interacts with the lymphocyte’s receptor.

Multiple Choice

A) Epitopes; immunogen
B) Allergens; allograft
C) Antigens; epitope
D) Immunogens; fragment

Answer 20

C) Antigens; epitope

Explanation: An antigen is a substance that provokes an immune response in specific lymphocytes. The term immunogen is another term for a substance that can elicit an immune response. A lymphocyte’s capacity to discriminate differences in molecular shape is so fine that it recognizes and responds to only a portion or molecular fragment that is specifically called the epitope.

Question 21

The electron transport system in bacteria is located on the _________blank and in eukaryotic cells on the _________blank.

Multiple Choice

A) plasmid; chloroplast
B) mitochondrion; cytoplasmic membrane
C) cytoplasmic membrane; mitochondrion
D) cell wall; mitochondrion

Answer 21

C) cytoplasmic membrane; mitochondrion

Question 22

Consider the following disease scenarios, and determine the correct mode of transmission for each.

1) Vehicle
2) Biological vector
3) Parenteral
4) Direct contact
5) Droplet
6) Healthcare-associated

Match each of the options above to the items below.

A) Syphilis from unprotected sex
B) Lyme disease
C) Salmonellosis from egg salad at a picnic
D) Chickenpox from one child coughing on another
E) Hepatitis B from needle sharing
F) MRSA

Answer 22

1) Vehicle
C) Salmonellosis from egg salad at a picnic

2) Biological vector
B) Lyme disease

3) Parenteral
E) Hepatitis B from needle sharing

4) Direct contact
A) Syphilis from unprotected sex

5) Droplet
D) Chickenpox from one child coughing on another

6) Healthcare-associated
F) MRSA

Question 23

Fever is initiated when a substance in circulation, called a _________blank, acts on the hypothalamus causing it to reset body temperature to a higher setting.

Multiple Choice

A) bacteriocin
B) transferrin
C) pyrogen
D) leukocidin

Answer 23

C) pyrogen

Explanation: Fever is initiated by pyrogens that act on the hypothalamus causing it to reset at a higher temperature. Exogenous pyrogens are products of infectious agents, and endogenous pyrogens are substances released by phagocytic cells.

Question 24

Match the terms related to recent advances in microbiology with their proper descriptions.

A) Microbiome
B) Polymerase Chain Reaction (PCR)
C) CRISPR
D) Small RNAs

Match each of the options above to the items below.

1) These molecules were first identified in the 2000s, and appear to play critical roles in regulating what happens in the cell.
2) This term is used to refer to all of the viruses, bacteria, fungi, and protozoa that call the human body home.
3) A newer technology that allows scientists to edit genes and provides potential to treat genetic diseases.
4) Invented by Kary Mullis in the 1980s, a method used to detect and amplify tiny amounts of DNA in a sample.

Answer 24

A) Microbiome
2) This term is used to refer to all of the viruses, bacteria, fungi, and protozoa that call the human body home.

B) Polymerase Chain Reaction (PCR)
4) Invented by Kary Mullis in the 1980s, a method used to detect and amplify tiny amounts of DNA in a sample.

C) CRISPR
3) A newer technology that allows scientists to edit genes and provides potential to treat genetic diseases.

D) Small RNAs
1) These molecules were first identified in the 2000s, and appear to play critical roles in regulating what happens in the cell.

Explanation: In the 1980s, Kary Mullis developed the PCR technique to amplify DNA fragments. Small RNAs were discovered in the 2000s, and play a role in gene regulation in cells. In 2008, the Human Microbiome project began, with findings released in 2012. The microbiome refers to all of the microorganisms that call our bodies home. CRISPR is a gene editing tool that was developed in the mid-2010s and has enormous potential for disease treatment.

Question 25

Select all of the differences between DNA and RNA to test your understanding of these nucleic acids. Check All That Apply A) DNA is double-stranded, whereas RNA is single-stranded. B) DNA nucleotides contain deoxyribose, whereas RNA nucleotides contain ribose. C) DNA contains the following nitrogenous bases: adenine (A), cytosine (C), guanine (G), and uracil (U); whereas RNA contains adenine, cytosine, guanine, and thymine. D) There are multiple types of DNA with different functions, whereas there is only one type of RNA.

Answer 25

A) DNA is double-stranded, whereas RNA is single-stranded. B) DNA nucleotides contain deoxyribose, whereas RNA nucleotides contain ribose. Explanation: While DNA and RNA are both nucleic acids, there are some key differences between them. DNA is double-stranded whereas RNA is single-stranded. DNA nucleotides contain deoxyribose, and RNA nucleotides contain ribose. DNA contains adenine, guanine, cytosine and thymine nitrogenous bases, and RNA contains adenine, guanine, cytosine, and uracil. There is one functional type of DNA, but multiple functional types of RNA including mRNA, rRNA, tRNA, miRNA, siRNA, and ribozymes.

Question 26

Select the characteristics exhibited by effective vaccines. Check All That Apply A) Little or no adverse side effects B) Protect against exposure to wild-type, natural pathogens C) Requires numerous doses or boosters D) Stimulate either a B-cell or a T-cell response E) Relatively long shelf life

Answer 26

A) Little or no adverse side effects B) Protect against exposure to wild-type, natural pathogens E) Relatively long shelf life Explanation: Effective vaccines induce both cell-mediated and humoral immunity while producing little to no side effects. The fewer the doses needed, the less expensive the vaccine is for patients. Ease of administration and extended shelf life also contribute to an effective vaccine.

Question 27

Diffusion is a general term referring to the net movement of atoms and molecules along a concentration gradient, from an area of low concentration to an area of high concentration. A) True B) False

Answer 27

B) False Explanation: Diffusion refers to the movement of atoms or molecules down a concentration gradient from an area of high concentration to an area of low concentration. Because the atoms or molecules are moving down their gradient, energy is not required, and therefore diffusion is a passive process.

Question 28

Which of the following represent epigenetic changes caused by a pathogen that can affect its ability to cause infection in the host? Check All That Apply A) Activation or inactivation of host cell DNA B) Binding to RNAs that silence genes C) Affect host cell DNA that is responsible for cytoskeleton organization D) Exchange of capsule genes between pathogen and host cell E) Secretion of endotoxin from the cell wall of a pathogen

Answer 28

A) Activation or inactivation of host cell DNA B) Binding to RNAs that silence genes C) Affect host cell DNA that is responsible for cytoskeleton organization Explanation: Microbes have been known to turn on or shut down host DNA. They do this by binding to host cell chromatin, histones, or silencing RNAs. They also have affected the cytoskeleton, causing disorganization of the cell.

Question 29

Select the statements that most accurately reflect immune dysfunction. Check All That Apply A) Cancer can be both a cause and an effect of immune dysfunction. B) Hyposensitivity diseases include autoimmune disorders. C) AIDS is a hypersensitivity disease. D) Hypersensitivity diseases can be due to normal immune reactions targeting healthy bystander tissue. E) Allergies are due to overreactivity of the immune system.

Answer 29

A) Cancer can be both a cause and an effect of immune dysfunction. D) Hypersensitivity diseases can be due to normal immune reactions targeting healthy bystander tissue. E) Allergies are due to overreactivity of the immune system. Explanation: Immunopathology is the study of disease states (immune dysfunctions) associated with overreactivity or underreactivity of the immune response. Overreactivity includes forms of allergy, hypersensitivity and autoimmunity. In immunodeficiency or underreactivity diseases, immune function is incompletely developed, suppressed, or destroyed.

Question 30

Reactions that use energy and synthesize building blocks into macromolecules are part of _________blank, whereas _________blank refers to cellular reactions that break larger molecules into smaller molecules and release energy. Multiple Choice A) anabolism; catabolism B) anabolism; amphibolism C) catabolism; anabolism D) amphibolism; catabolism

Answer 30

A) anabolism; catabolism Explanation: Metabolism includes anabolism, the synthesizing, energy-requiring reactions, and catabolism, the degradative reactions that release energy.

Question 31

Choose the phrase that best describes the role of viral surface proteins or spikes. Multiple Choice A) Inject viral nucleic acid into host cell B) Allow viruses to bind to each other C) Enable replication of the viral nucleic acid D) Provide means of attachment to host cell surface E) Provide means for viruses to exchange nucleic acid

Answer 31

D) Provide means of attachment to host cell surface Explanation: Many viruses have surface proteins that project outward from the capsid or envelope. These proteins provide a means for the virus to attach to a host cell, the first step in establishing an infection.

Question 32

All organisms studied in microbiology must be viewed with a microscope. A) True B) False

Answer 32

B) False Explanation: Bacteria and viruses are microscopic but some protozoans and algae are visible to the naked eye. Also, helminths, easily viewed by the naked eye in their adult forms, are studied in microbiology because they have microscopic forms in their life cycles.

Question 33

Select the characteristics of biofilms that differentiate them from planktonic bacteria. Check All That Apply A) Microorganisms live singly and independently. B) Microorganisms participate in quorum sensing. C) Microorganisms secrete extracellular material, usually polysaccharide, that forms a matrix. D) Microorganisms are readily eradicated using antibiotics. E) Microorganisms exist as part of a diverse interdependent community.

Answer 33

B) Microorganisms participate in quorum sensing. C) Microorganisms secrete extracellular material, usually polysaccharide, that forms a matrix. E) Microorganisms exist as part of a diverse interdependent community. Explanation: Biofilms are diverse microbial communities in which the different members exist in an interdependent relationship. Extracellular polysaccharides or proteins form a matrix that becomes the ground substance of the biofilm. Microorganisms within the biofilm participate in a type of communication referred to as quorum sensing. Microorganisms within a biofilm community are less likely to respond to antibiotics than their planktonic (independent-living) counterparts.

Question 34

The time required for one complete cycle of binary fission is known as the _________blank, or generation time. Multiple Choice A) mating B) mitotic C) meiotic D) doubling

Answer 34

D) doubling Explanation: This division is referred to as doubling time, because each generation involves one bacterial cell dividing into two daughter cells.

Question 35

Match the type of epidemic curve associated with each example. 1) Potato salad sits out too long at the picnic, and everyone that ate the dish suffered from vomiting later in the evening. 2) Every winter, flu spreads rapidly through the United States. 3) Typhoid Mary was an asymptomatic carrier of Salmonella, and she unknowingly transmitted the bacteria to many members of the families that she served as a cook. Match each of the options above to the items below. A) Point-source epidemic B) Common-source epidemic C) Propagated epidemic

Answer 35

1) Potato salad sits out too long at the picnic, and everyone that ate the dish suffered from vomiting later in the evening. A) Point-source epidemic 2) Every winter, flu spreads rapidly through the United States. C) Propagated epidemic 3) Typhoid Mary was an asymptomatic carrier of Salmonella, and she unknowingly transmitted the bacteria to many members of the families that she served as a cook. B) Common-source epidemic

Question 36

The theory of evolution was once a __________ that was tested repeatedly and always supported by the data collected by various scientists around the world. Multiple Choice A) variable B) theorem C) hypothesis D) fact

Answer 36

C) hypothesis Explanation: The theory of evolution was once a hypothesis. It has since been tested time and time again through the scientific method without being disproven and therefore, it was elevated to the level of a theory.

Question 37

Select the type of T cell that plays a role in diminishing an immune response. Multiple Choice A) TREG B) T1H C) TC D) T17H

Answer 37

A) TREG Explanation: TREG cells play a role in dampening down immune responses. They work to prevent autoimmunity, disruption of the normal biota, and unnecessary inflammation.

Question 38

Nonpolar molecules like benzene cannot be dissolved in: Multiple Choice A) polar fluids, like water. B) nonpolar fluids, like alcohol. C) the lab. D) anything.

Answer 38

A) polar fluids, like water.

Question 39

Enterovirus is a properly written genus designation for a group of viruses including poliovirus and coxsackievirus. A) True B) False

Answer 39

A) True Explanation: The name of a viral genus is capitalized and written in italics.

Question 40

Match the technologies with the statements that most accurately describe them to test your understanding how microorganisms are useful in society today. A) Bioremediation B) Genetic Engineering C) Biotechnology Match each of the options above to the items below. 1) Technology that applies the power of microbes toward the manufacture of industrial products, foods, and drugs. 2) Newer technology that manipulates the genetics of microbes, plants and animals to create new products and genetically modified organisms (GMOs). 3) Process that involves the introduction of microbes into the environment to restore stability or to clean up toxic pollutants.

Answer 40

A) Bioremediation 3) Process that involves the introduction of microbes into the environment to restore stability or to clean up toxic pollutants. B) Genetic Engineering 2) Newer technology that manipulates the genetics of microbes, plants and animals to create new products and genetically modified organisms (GMOs). C) Biotechnology 1) Technology that applies the power of microbes toward the manufacture of industrial products, foods, and drugs. Explanation: Although humans have been harnessing the work of microorganisms for thousands of years (bread making, alcohol production, special cheeses), new technologies have arisen recently to expand their use. Biotechnology is a broad field of science that takes advantage of microbes' abilities to create industrial products, foods, and drugs. Genetic engineering, an area of biotechnology, has permitted the genetic alteration of microbes and other organisms to create genetically modified organisms (GMOs) with unique and desirable traits. Examples include nutrient-rich foods and herbicide-resistant plants. Bioremediation has allowed microbes to use their own metabolic traits to clean up various wastes in human society, such as massive oil spills.

Question 41

Which of the following would be used to identify an unknown bacterial culture that came from a patient in the intensive care unit? Multiple Choice A) Gray’s Anatomy B) Bergey’s Manual of Determinative Bacteriology C) The Physician’s Desk Reference D) Bergey’s Manual of Systematic Bacteriology

Answer 41

B) Bergey’s Manual of Determinative Bacteriology

Question 42

Although both aerobic respiration and anaerobic respiration utilize glycolysis, the Krebs cycle, and an electron transport system, _________blank respiration uses O2 as the final electron acceptor at the end of the electron transport system, whereas _________blank respiration uses an inorganic molecule other than O2 as the final electron acceptor. Multiple Choice A) aerobic; fermentative B) aerobic; anaerobic C) fermentative; aerobic D) anaerobic; aerobic

Answer 42

B) aerobic; anaerobic Explanation: In aerobic respiration, oxygen gas (O2) is the final electron acceptor at the end of the electron transport system. In anaerobic respiration, an inorganic molecule other than O2 is the final electron acceptor. An example of a common electron acceptor used in anaerobic respiration is nitrate (NO3−).

Question 43

Choose the phrase that best describes photosynthesis. Multiple Choice A) A process which uses light energy to fuel anabolic reactions such as the assembly of large polysaccharides B) A process which harvests light energy and converts it to chemical energy, which is used to split glucose into two molecules of pyruvic acid C) A process which harvests light energy and converts it to chemical energy (ATP and NADPH) that is then used to “fix” or transform CO2 into organic compounds such as sugars D) A process which occurs in plants and converts solar energy to sugars

Answer 43

C) A process which harvests light energy and converts it to chemical energy (ATP and NADPH) that is then used to “fix” or transform CO2 into organic compounds such as sugars Explanation: Photosynthesis is a process which uses chlorophyll pigments to capture solar energy and convert it to chemical energy (ATP and NADPH). This chemical energy is then used to reduce CO2 to form organic compounds such as sugars. In the process, water is split and O2 gas is released, and CO2 gas is utilized.

Question 44

Some strains of human papillomavirus (HPV) can cause cellular changes that lead to the development of cervical cancer. Infections by such oncogenic viruses are known as: Multiple Choice A) latent infections. B) persistent infections. C) chronic infections. D) transforming infections.

Answer 44

D) transforming infections. Explanation: The effect on cells by cancer-inducing viruses is termed transformation because they "transform" the cell from a normal cell to a cell with an abnormally increased rate of growth.

Question 45

The chemical in which energy is stored in cells is called: Multiple Choice A) cAMP. B) AMP. C) ATP. D) cADP.

Answer 45

C) ATP. Explanation: The most readily available energy storage molecule in cells is ATP (adenosine triphosphate). The bonds between the phosphates are high-energy bonds, and this energy is easily released when these bonds are broken.

Question 46

Salting of meat prior to the development of refrigeration technology was an example of using osmotic pressure to control microbial spoilage of this food product. A) True B) False

Answer 46

A) True Explanation: Salting of meat and fish, as well as sugaring of fruit, are examples of osmotic pressure methods of microbial control.

Question 47

Choose the statement that best describes the role of the Calvin cycle in photosynthesis. Multiple Choice A) The Calvin cycle is a light-capturing series of reactions that convert light energy to chemical energy. B) The Calvin cycle is the “synthesis” part of photosynthesis, the set of reactions that actually convert CO2 to organic carbon compounds. C) The Calvin cycle splits water and releases the electrons that are used to reduce CO2. D) The Calvin cycle is synonymous with the light-dependent reactions of photosynthesis.

Answer 47

B) The Calvin cycle is the “synthesis” part of photosynthesis, the set of reactions that actually convert CO2 to organic carbon compounds. Explanation: The Calvin cycle is actually the “synthesis” part of photosynthesis, in which CO2 is reduced to form organic compounds. It is synonymous with the light-independent reactions.

Question 48

Alpha helices and beta pleated sheets are examples of the __________ level of protein structure. Multiple Choice A) tertiary B) secondary C) primary D) quaternary

Answer 48

B) secondary Explanation: There are four levels of protein structure. Alpha helices and beta pleated sheets are two different forms of secondary structure, which form due to hydrogen bonding between functional groups on the amino acids that make up the primary chain.

Question 49

Select all of the sites where normal microbiota have been definitively found in humans. Check All That Apply A) Brain B) Mouth C) Liver D) Throat E) Large intestine F) Skin G) Vagina

Answer 49

B) Mouth D) Throat E) Large intestine F) Skin G) Vagina Explanation: The mouth, throat (upper respiratory tract), large intestine, skin, and vagina all have normal microbiota. The brain and liver do not appear to have normal microbiota, although microbial DNA has been detected in the brain. This information may continue to change as the Human Microbiome Project progresses.

Question 50

Choose the statement that indicates how cytopathic effects are detected. Multiple Choice A) Performing biochemical tests on infected cells B) Performing immunological tests on infected cells C) Growing infected cells in a variety of different media D) Examining infected cells with a microscope

Answer 50

D) Examining infected cells with a microscope Explanation: Cytopathic effects (CPEs) indicate viral damage to a cell. In order to detect cytopathic effects, the infected cells must be examined microscopically. Examples of changes include size and shape alterations, inclusion bodies, and the fusion of multiple host cells into one large cell (syncytium).

Question 51

Transfusion of the wrong blood type can cause: Multiple Choice A) recipient antibody activation of the complement cascade to attack the RBCs. B) fever and anemia. C) systemic shock and kidney failure. D) massive hemolysis of the donor RBCs. E) All of the choices are correct.

Answer 51

E) All of the choices are correct.

Question 52

Identify the process or environment in this list that is not affected by microorganisms. Multiple Choice A) Oxygen cycles B) Recycling of dead organisms C) All of these choices have microbial involvement. D) Human health

Answer 52

C) All of these choices have microbial involvement.

Question 53

Match the terms to their correct descriptions to review the types of carrier states. 1) Incubating carrier 2) Passive carrier 3) Convalescent carrier 4) Chronic carrier 5) Asymptomatic carrier Match each of the options above to the items below. A) Infected, but shows no symptoms of disease B) Spreads the infectious agent before the appearance of the first symptoms C) Recuperating patients without symptoms; may shed viable microbes D) Shelters the infectious agent in a latent form for a long period after recovery E) Healthcare workers who accidentally transfer pathogens to patients

Answer 53

1) Incubating carrier B) Spreads the infectious agent before the appearance of the first symptoms 2) Passive carrier E) Healthcare workers who accidentally transfer pathogens to patients 3) Convalescent carrier C) Recuperating patients without symptoms; may shed viable microbes 4) Chronic carrier D) Shelters the infectious agent in a latent form for a long period after recovery 5) Asymptomatic carrier A) Infected, but shows no symptoms of disease Explanation: When describing carrier states, it is important to first consider if the carrier is infected themselves. If they are not infected, they are passive carriers that simply transmit the organism through handling of patients or the patient's environment. If they are infected, what stage of the infection are they in? Incubation period or the convalescent (recovering) period? Do they show signs and symptoms of infection, or are they asymptomatic carriers able to transmit the infection (such as many cases of gonorrhea and HPV)? Have they already recovered themselves but still harbor and shed the agent, such as with tuberculosis or typhoid fever?

Question 54

Enzymes act as catalysts to lower what aspect of a chemical reaction? Multiple Choice A) Activation energy B) Binding site availability C) Product concentration D) Noncompetitive inhibitor status

Answer 54

A) Activation energy Explanation: Enzymes are catalysts that reduce the activation energy of a chemical reaction. This is the certain amount of energy needed to initiate a reaction. Enzymes help overcome this resistance.

Question 55

Select the physical methods of microbial control. Check All That Apply A) Moist heat B) Phenolics C) Cold D) UV radiation E) Halogens F) Osmotic pressure

Answer 55

A) Moist heat C) Cold D) UV radiation F) Osmotic pressure Explanation: The six methods of physical control of microorganisms include heat, cold, radiation, filtration, desiccation, and osmotic pressure. Halogens and phenolics are both groups of chemicals that can be used in control.

Question 56

Which of the following is a macromolecule that assembles into bilayers? Multiple Choice A) Carbohydrate B) Nucleic acid C) Protein D) Phospholipid

Answer 56

D) Phospholipid

Question 57

Select all of the agents that will kill a microbial pathogen or completely inactivate its ability to cause disease. Check All That Apply A) Bacteristat B) Fungistat C) Virucide D) Germicide E) Sporicide

Answer 57

C) Virucide D) Germicide E) Sporicide Explanation: Any agent labeled “–cidal” will kill the target organism. A bactericidal chemical will kill bacteria. A chemical labeled as bacteriostatic will not kill, but will inhibit the growth of the bacteria. The root “–static” means to stop or inhibit.

Question 58

Endospores are reproductive structures produced by multiple bacterial cell divisions, with one vegetative cell producing many endospores. A) True B) False

Answer 58

B) False Explanation: Endospores are not reproductive structures. One vegetative cell will form one endospore. When the spore is released, the vegetative cell (sporangium) is lysed. When the endospore germinates, it will form one vegetative cell.

Question 59

What will be the immediate action of an allergen when it enters the body for a second time? Multiple Choice A) Binding of allergen to adjacent IgE binding sites on mast cells and basophils B) Degranulation C) Prostaglandins cause vasodilation and increased vascular permeability D) Histamine acts on smooth muscle E) Binding of IgE by the Fc region to mast cells and basophils

Answer 59

A) Binding of allergen to adjacent IgE binding sites on mast cells and basophils

Question 60

A chemiclave is a piece of equipment that uses what antimicrobial agent for the purpose of sterilization? Multiple Choice A) Hydrochloric acid B) Ethylene oxide C) Silver nitrate D) Carbon dioxide

Answer 60

B) Ethylene oxide Explanation: Ethylene oxide can be used in a chemiclave. Such gas sterilization can be used to sterilize items that would be damaged by heat or liquids. It is used to sterilize plastics and a large variety of prepackaged medical devices, surgical supplies, syringes, and plastic lab supplies such as petri dishes and test tubes. Ethylene oxide can also be used to disinfect some dried foods, spices, and drugs. It is not used to sterilize bacterial media or milk and dairy products.

Question 61

Select the cell counting methods that enable only living cells to be counted. Check All That Apply A) Viable plate count B) Direct cell count C) Flow cytometry D) Coulter counter E) Turbidometry

Answer 61

A) Viable plate count C) Flow cytometry Explanation: While all of these methods can be used to count bacterial cells, two of them enable counting of only living cells. The viable plate count requires the growth of the cells to be counted, and thus counts only living cells. Flow cytometry can be adjusted to differentiate between living and dead cells, and this makes it possible to count only living cells. Direct cell counts, the Coulter counter, and turbidometry are unable to distinguish between living and dead cells, and thus both are counted.

Question 62

Cationic detergents are surface active agents, also known as _________blank, which damage bacteria by binding bacterial surface proteins and disrupting _________blank. Multiple Choice A) surfactants; cell membranes B) peroxides; capsules C) aqueous solutions; flagellar action D) tinctures; ribosomes

Answer 62

A) surfactants; cell membranes Explanation: Cationic detergents are surfactants that disrupt the cell membranes of bacteria.

Question 63

Immunopathology is defined as: Multiple Choice A) the study of immune imbalance, whether hyper- or hypoactivity. B) the study of AIDS. C) the study of autoimmune diseases. D) the study of immunodeficiencies.

Answer 63

A) the study of immune imbalance, whether hyper- or hypoactivity.

Question 64

The ability of a nonpathogen or weakly pathogenic microorganism to cause disease primarily in an immunocompromised host is termed a/an _________blank infection. Multiple Choice A) pathogenic B) opportunistic C) virulent D) antagonistic

Answer 64

B) opportunistic Explanation: If a host’s immune system is sufficiently compromised, a nonpathogenic or weakly pathogenic microorganism may be able to cause disease. These are often called opportunistic infections.

Question 65

The sum total of the genetic material of a cell is its: Multiple Choice A) transcriptome. B) proteose. C) genome. D) genes.

Answer 65

C) genome Explanation: The genome is the sum total of the genetic material of a cell. It includes DNA found in the nucleus or nucleoid region of cells as well as DNA in other locations such as mitochondria, chloroplasts, or plasmids.

Question 66

Select all of the phrases below that represent the structure and function of enzymes. Check All That Apply A) Composed of protein B) Increase the rate of chemical reactions C) Are used up in chemical reactions D) High concentrations are necessary for activity E) Activity is affected by temperature and pH F) Activity is affected by regulatory mechanisms G) Become incorporated into the reaction product H) Have active sites with which substrates interact I) Enzyme increase the activation energy of a reaction

Answer 66

A) Composed of protein B) Increase the rate of chemical reactions E) Activity is affected by temperature and pH F) Activity is affected by regulatory mechanisms H) Have active sites with which substrates interact Explanation: Enzymes are the critical molecules which enable and control cellular metabolism. Enzymes are composed of protein. As such, their activity is affected by temperature and pH. Enzymes increase the rate of chemical reactions within the cell and their activity can be adjusted by a variety of regulatory mechanisms. Enzymes are much larger than the substrates with which they interact. Generally, the substrate must fit into the active site of the enzyme. Enzymes work by lowering the activation energy of a reaction. They are recycled and are not used up in a reaction, so they can operate at very low concentrations. They are not incorporated into the reaction products.

Question 67

Select the statement that accurately characterizes ATP. Multiple Choice A) It is generated by a catabolic reaction. B) It contains the nitrogen base cytosine. C) It contains three phosphate molecules. D) It contains five high-energy bonds.

Answer 67

C) It contains three phosphate molecules. Explanation: ATP contains adenosine and three phosphate molecules. The synthesis of ATP involves the formation of a bond between ADP and a phosphate group, an anabolic reaction.

Question 68

Select all of the statements that characterize obligate saprobes. Check All That Apply A) They live in a host. B) They live on a host. C) They feed off of dead organic matter in water. D) They feed off of dead organic matter in soil. E) They lack enzymes to degrade organic matter.

Answer 68

C) They feed off of dead organic matter in water. D) They feed off of dead organic matter in soil. Explanation: Obligate saprobes must live off of dead organic matter in soil or water, and they cannot adapt to a host.

Question 69

What component provides for a stronger cell wall structure in gram-positive cells in comparison to gram-negative cells? Multiple Choice A) Outer membrane B) Lipopolysaccharide C) Teichoic acids D) Phospholipids E) Thick peptidoglycan layer

Answer 69

E) Thick peptidoglycan layer Explanation: It is the thickness of the peptidoglycan layer that makes gram-positive cell walls stronger than gram-negative cells walls. The teichoic acids in gram-positive cell walls do not significantly contribute to the strength of the cell wall. Both cell types have phospholipids in their cell membrane. Gram-positive cells do not have an outer membrane or lipopolysaccharide.

Question 70

What represents a nonionizing form of radiation, often used for disinfection purposes? Multiple Choice A) Cathode rays B) UV radiation C) Gamma rays D) X rays

Answer 70

B) UV radiation Explanation: Ionizing radiation such as gamma radiation is used for cold sterilization of a variety of items, including plastics, pharmaceuticals, and foods. Nonionizing radiation, also known as UV light, doesn’t penetrate well, but can readily be used for disinfection purposes.

Question 71

How may this tree have been drawn differently prior to genetic analysis of ribosomal RNA and the subsequent development of the three domain classification system? Multiple Choice A) The organisms listed in Domain Bacteria and Domain Archaea would be coming off the same branch, rather than Domain Archaea coming off the same branch as Domain Eukarya. B) The organisms listed in Domain Bacteria and Domain Eukarya would be coming off the same branch, rather than Domain Archaea coming off the same branch as Domain Eukarya. C) The organisms listed in all three domains would be separately coming off the ancestral cell line box. D) There would be no significant changes to the branching of this tree.

Answer 71

A) The organisms listed in Domain Bacteria and Domain Archaea would be coming off the same branch, rather than Domain Archaea coming off the same branch as Domain Eukarya. Explanation: Originally, archaea and bacteria were part of the same kingdom (Monera) because of their structural similarities.

Question 72

Solutions of antimicrobial chemicals dissolved in pure water are termed tinctures, while those dissolved in pure alcohol are termed aqueous. A) True B) False

Answer 72

B) False Explanation: The opposite is true. Solutions of antimicrobial chemicals dissolved in pure water are termed aqueous, while those dissolved in pure alcohol are termed tinctures.

Question 73

Select the electron carriers used by cells. Check All That Apply A) Glucose B) NAD C) FAD D) ATP E) NADP

Answer 73

B) NAD C) FAD E) NADP Explanation: The electron carriers used by cells include NAD (nicotinamide adenine dinucleotide), FAD (flavin adenine dinucleotide), and NADP (nicotinamide adenine dinucleotide phosphate).

Question 74

The study of the frequency and distribution of a disease in a defined population is Multiple Choice A) pathology. B) clinical microbiology. C) epidemiology. D) immunology. E) medicine.

Answer 74

C) epidemiology.

Question 75

Select the statements that are true of inducible operons to test your understanding of the differences between inducible and repressible operons. Check All That Apply A) Inducible operons often contain genes for enzymes that function in catabolic processes. B) Inducible operons are usually in the “turned on” state and are 'turned off' when not needed. C) The inducer is often the product of the enzymes encoded. D) Inducible operons will be “turned on” in the presence of the substrate and turned off in its absence. E) The lac operon is an example of an inducible operon.

Answer 75

A) Inducible operons often contain genes for enzymes that function in catabolic processes. D) Inducible operons will be “turned on” in the presence of the substrate and turned off in its absence. E) The lac operon is an example of an inducible operon. Explanation: Inducible operons usually encode enzymes required for catabolic processes. This means that the enzymes necessary for the catabolism of that substrate will only be produced when that substrate is present. These operons are in the “off” state when the substrate is absent. The lac operon is an example of an inducible operon.

Question 76

Match the bacterial shapes with the appropriate description. A) Bacillus B) Coccus C) Spirillum and spirochete Match each of the options above to the items below. 1) Spherical cell 2) Cylindrical or rod-shaped cell 3) Spiral or helical-shaped cell

Answer 76

A) Bacillus 2) Cylindrical or rod-shaped cell B) Coccus 1) Spherical cell C) Spirillum and spirochete 3) Spiral or helical-shaped cell Explanation: Spherical bacterial cells are called cocci (coccus, singular). A cylindrical or rod-shaped cell is referred to as a bacillus. A spiral or helical-shaped cell is called a spirillum or a spirochete.

Question 77

The clear fluid found in whole blood in which the cells are suspended is called _________blank; however, when the clotting factors are removed, it is now called _________blank. Multiple Choice A) whole blood; serum B) serum; plasma C) plasma; serum D) plasma; whole blood

Answer 77

C) plasma; serum Explanation: Plasma is the fluid that suspends the cells in whole blood; when clotting factors are removed, the fluid is now called serum.

Question 78

Koch's postulates help to determine: Multiple Choice A) correlation. B) predisposition. C) randomization. D) causation.

Answer 78

D) causation.

Question 79

The relative ability of a microbe to establish itself in a host and cause disease is referred to as: Multiple Choice A) opportunism. B) exogenous. C) virulence. D) variance.

Answer 79

C) virulence. Explanation: Virulence is a very closely related term to the word "pathogenicity" and indicates a microbe's relative ability to cause disease.

Question 80

Match the macromolecules to their function within cells. A) Proteins B) Carbohydrates C) Nucleic acids D) Lipids Match each of the options above to the items below. 1) Major structural component of cell walls 2) Major component of cell membranes 3) Speed up and facilitate chemical reactions within cells 4) Inheritance and expression of genetic traits

Answer 80

A) Proteins 3) Speed up and facilitate chemical reactions within cells B) Carbohydrates 1) Major structural component of cell walls C) Nucleic acids 4) Inheritance and expression of genetic traits D) Lipids 2) Major component of cell membranes Explanation: Cell walls typically contain carbohydrates such as cellulose, peptidoglycan, or chitin. Lipids, more specifically phospholipids, are a major component of cell membranes. Many proteins in cells are enzymes which facilitate or catalyze chemical reactions. Nucleic acids (DNA and RNA) encode genetic traits and provide for inheritance.

Question 81

The initial encounter with an allergen is called the _________blank dose. Multiple Choice A) sensitizing B) allergic C) hypersensitivity D) provocative E) desensitizing

Answer 81

A) sensitizing

Question 82

Select the term that refers to a microbe able to survive very low pH conditions. Multiple Choice A) Osmophile B) Acidophile C) Halophile D) Alkalinophile

Answer 82

B) Acidophile Explanation: Acidophiles thrive in low pH environments.

Question 83

Select characteristics of the lymphatic system to test your understanding of its structure and major functions. Check All That Apply A) Provides a route to extract fluid from circulation in order to diffuse into extracellular spaces B) Helps to regulate the inflammatory response by acting as a “drain-off” system C) Moves like the blood in response to pumping by the heart D) Lymph contains a number of immune cells and their products to defend against pathogens E) Lymph can flow to and from the heart

Answer 83

B) Helps to regulate the inflammatory response by acting as a “drain-off” system D) Lymph contains a number of immune cells and their products to defend against pathogens Explanation: The lymphatic system is full of immune response cells and their products to defend against foreign invaders. Lymph moves due to the squeezing of the muscles in one direction towards the heart. The system provides a route for the return of extracellular fluid and thus can serve as a drain-off system during inflammation.

Question 84

Select the three choices that represent the primary purposes of cultivating viruses. Check All That Apply A) To isolate viruses from clinical specimens B) To produce chemicals such as alcohol and acetone C) To produce virus for bioweapons use D) To prepare viruses for vaccines E) To research the biology of viruses

Answer 84

A) To isolate viruses from clinical specimens D) To prepare viruses for vaccines E) To research the biology of viruses Explanation: Viruses can be cultivated in the laboratory for a variety of reasons. The three primary reasons are (1) to isolate viruses from clinical specimens, (2) to prepare viruses for vaccines, and (3) to research the biology of viruses. Viruses may be cultivated in live animals, bird embryos, or in cell cultures.

Question 85

Select the terms that describe the possible configurations of viral nucleic acids. Check All That Apply A) Single-stranded DNA B) Double-stranded DNA, linear C) Double-stranded DNA-RNA hybrid D) Double-stranded DNA, circular E) Single-stranded RNA, positive-sense F) Single-stranded RNA, negative-sense G) Double-stranded RNA

Answer 85

A) Single-stranded DNA B) Double-stranded DNA, linear D) Double-stranded DNA, circular E) Single-stranded RNA, positive-sense F) Single-stranded RNA, negative-sense G) Double-stranded RNA Explanation: Viral nucleic acids display a large variety of configurations. Among DNA viruses, the DNA may be typical double-stranded DNA, either linear or circular, or it may be single-stranded DNA. RNA viruses may have double-stranded RNA or single-stranded RNA genomes. Depending on whether the single RNA strand is immediately ready for translation or has to be converted into the proper form, it is referred to as positive-sense RNA or negative-sense RNA, respectively.

Question 86

Select all of the statements that are true of fermentation. Check All That Apply A) It does not require O2 B) It uses glycolysis, the Krebs cycle, and an electron transport system. C) Two ATP are produced (per molecule of glucose). D) No NADH is produced. E) The final electron acceptor is an organic molecule, usually pyruvic acid or a derivative. F) Different fermentation pathways can produce ethanol, CO2, lactic acid, or other organic acids. G) It is only done by yeast.

Answer 86

A) It does not require O2 C) Two ATP are produced (per molecule of glucose). E) The final electron acceptor is an organic molecule, usually pyruvic acid or a derivative. F) Different fermentation pathways can produce ethanol, CO2, lactic acid, or other organic acids. Explanation: Fermentation is an alternative to aerobic and anaerobic respiration. The primary pathway followed is glycolysis, with the production of 2 ATP (net) and 2 NADH. In fermentation, the electrons carried by NADH are transferred to either pyruvic acid or a derivative of pyruvic acid. Fermentation end products include ethanol, CO2, lactic acid, and a variety of other organic acids. Fermentation can be used by yeast, bacteria, and even our muscles (temporarily).

Question 87

Select the statements that accurately reflect lymphocyte receptors. Check All That Apply A) Only B cell receptors are made by genetic recombination. B) In contrast to B cell receptors, T cell receptors are never secreted. C) B cell receptors are immunoglobulins. D) The shape of antigen binding sites on lymphocyte receptors is not variable. E) Both B and T cell receptors are inserted into the cell membrane of their respective lymphocyte.

Answer 87

B) In contrast to B cell receptors, T cell receptors are never secreted. C) B cell receptors are immunoglobulins. E) Both B and T cell receptors are inserted into the cell membrane of their respective lymphocyte. Explanation: B and T cell receptors are similar in that they are both cell membrane-associated and have hypervariable antigen binding regions. B cell receptors are immunoglobulins that are secreted as antibodies when the cell is stimulated by antigen.

Question 88

The minimum number of microorganisms necessary to enter the body and establish infection is termed the: Multiple Choice A) infectious dose. B) virulence dose. C) disease dose. D) minimal dose.

Answer 88

A) infectious dose. Explanation: The minimum number of microorganisms necessary to enter through the portal of entry and establish infection is the infectious dose. Usually, organisms with greater virulence require a smaller infectious dose.

Question 89

Viral spikes are used for: Multiple Choice A) attachment to host cells. B) lysogeny. C) replication of RNA. D) conjugation.

Answer 89

A) attachment to host cells. Explanation: Viral spikes allow for attachment to specific host cells. For example, certain spike proteins on HIV attach to specific receptors on certain types of white blood cells.

Question 90

Base substitutions, deletions, and insertions describe mutations in terms of their effect on the _________blank, whereas missense, nonsense, and silent describe mutations in terms of their effect on the _________blank. Multiple Choice A) telomere; chromatin B) DNA; protein C) valence; gene D) exon; intron

Answer 90

B) DNA; protein Explanation: The terms base substitution, insertion, and deletion describe mutations in terms of their affect on the DNA, whereas the terms missense, nonsense, and silent describe mutations in terms of their affect on the resulting polypeptide or protein.

Question 91

From the list below, select all of the passive transport mechanisms used by cells. Check All That Apply A) Simple diffusion B) Carrier mediated active transport C) Group translocation D) Facilitated diffusion E) Endocytosis

Answer 91

A) Simple diffusion D) Facilitated diffusion Explanation: Passive transport includes simple diffusion directly through the plasma membrane, and facilitated diffusion in which substances diffuse with the help of a carrier protein located in the cell membrane.

Question 92

The two microbial forms most resistant to chemical and physical control measures are _________blank or proteinaceous infectious particles, and _________blank produced by Bacillus and Clostridium species. Multiple Choice A) prions; endospores B) ribozymes; capsules C) micro RNAs; envelopes D) porins; granzymes

Answer 92

A) prions; endospores Explanation: Prions are extremely resistant to chemical and physical control measures, and special protocols are necessary to destroy them. Endospores, produced by bacteria in several genera such as Bacillus and Clostridium, are also very resistant to microbial control measures, and all sterilization techniques are designed to be able to destroy endospores.

Question 93

From the list below, select all of the active transport mechanisms used by cells. Check All That Apply A) Simple diffusion B) Carrier mediated active transport C) Group translocation D) Facilitated diffusion E) Endocytosis

Answer 93

B) Carrier mediated active transport C) Group translocation E) Endocytosis Explanation: Active transport mechanisms require the expenditure of energy as items are transported “up” their concentration gradient from an area of low concentration to an area of higher concentration. Active transport mechanisms include carrier mediated active transport, group translocation, and endocytosis. Endocytosis can be further subdivided into two types, phagocytosis and pinocytosis.

Question 94

Match the carbohydrate class with an example of a carbohydrate in that class. A) Disaccharide B) Polysaccharide C) Monosaccharide Match each of the options above to the items below. 1) Fructose 2) Lactose 3) Cellulose

Answer 94

A) Disaccharide 2) Lactose B) Polysaccharide 3) Cellulose C) Monosaccharide 1) Fructose Explanation: Fructose is a single sugar, or monosaccharide. Lactose is a disaccharide composed of glucose and galactose joined by a glycosidic bond. Cellulose is a polysaccharide.

Question 95

Select the type of RNA molecule that is associated with an amino acid, which is used to build a polypeptide chain during translation. Multiple Choice A) rRNA B) mRNA C) microRNA D) tRNA

Answer 95

D) tRNA Explanation: tRNA molecules are bound to an amino acid which can then be transferred to the growing polypeptide chain during translation.

Question 96

When a cell is infected by a virus, synthesis of _________blank begins and this protein diffuses away from the infected cell to protect nearby uninfected cells by binding to surface receptors and initiating synthesis of antiviral proteins. Multiple Choice A) interleukin B) streptokinase C) endonuclease D) interferon

Answer 96

D) interferon Explanation: Interferons are produced by infected cells but act on uninfected cells to initiate antiviral proteins to prevent viruses from invading the protected cells.

Question 97

Normal biota appear to contribute to first-line defense mechanisms through Multiple Choice A) biofilm formation. B) microbial polymorphism. C) microbial antagonism. D) restriction analysis.

Answer 97

C) microbial antagonism. Explanation: Normal biota can exert an antagonistic effect against potential pathogens attempting to colonize a tissue. They do this by limiting the space or nutrients available to these pathogens or by altering the environment to be unfavorable for their growth (e.g. pH levels).

Question 98

Choose the term that describes a virus that has a membranous outer covering over its capsid. Multiple Choice A) Icosahedral virus B) Naked virus C) Encapsulated virus D) Enveloped virus E) Coated virus

Answer 98

D) Enveloped virus Explanation: This membranous covering is called an envelope, and viruses which have such a covering are called “enveloped” viruses. A virus which lacks this covering is referred to as a “naked” virus. Enveloped viruses acquire their membranous coverings as they bud off the host cell membrane or from membranous organelles inside the host cell. However, the virus does place its own proteins into the envelope. Therefore, the envelope is partially derived from the host cell but does differ from the host cell membrane.

Question 99

To find listings and charts of biochemical tests that can be used to identify unknown bacteria, you could use Multiple Choice A) Bergey's Manual of Genotypic Analysis. B) Bergey's Manual of Bacterial Typing. C) Bergey's Manual of Systematic Bacteriology. D) Bergey's Manual of Determinative Bacteriology.

Answer 99

D) Bergey's Manual of Determinative Bacteriology. Explanation: There are two different Bergey’s manuals. The Bergey’s Manual of Determinative Bacteriology provides information on identifying prokaryotes based on phenotypic (morphology, biochemical) characteristics. This would be the most useful for finding information on how to identify unknown bacteria. Bergey’s Manual of Systematic Bacteriology provides information on prokaryotic evolutionary relationships based on rRNA sequencing information and phenotypic traits. While comprehensive, this manual is less useful from the practical standpoint of identifying unknown bacteria.

Question 100

The first stage of the specific immune response involves: Multiple Choice A) the challenge of B or T cells by antigens. B) the presentation of antigens. C) lymphocyte development and differentiation. D) the production of antibodies.

Answer 100

C) lymphocyte development and differentiation. Explanation: Specific immunity starts off with lymphocyte differentiation from a bone marrow stem cell and then the maturation of B cells in the bone marrow and T cells in the thymus.

Question 101

The scientific method is used by scientists to explain a certain natural phenomenon, and it involves the formation of a __________ as a tentative explanation of the observed or measured phenomenon. Multiple Choice A) experiment B) hypothesis C) theory D) variable

Answer 101

B) hypothesis Explanation: Science is a process of investigation, using observation, experimentation, and reasoning. The scientific method is a process for investigating events or phenomena around us, and the investigation starts with the formulation of a hypothesis or a supposition of why the event occurred.

Question 102

Select the characteristics of a chemical control agent that make it a desirable agent. Check All That Apply A) Corrosive to metals and plastics B) Water or alcohol soluble and stable C) "-cidal" to a wide range of microbes, but nontoxic to humans and animal tissue D) Rapidly effective in low concentrations E) Ineffective in the presence of organic matter F) Inexpensive G) Short-lived, spontaneously inactivates with time

Answer 102

A) Corrosive to metals and plastics B) Water or alcohol soluble and stable C) "-cidal" to a wide range of microbes, but nontoxic to humans and animal tissue D) Rapidly effective in low concentrations F) Inexpensive Explanation: Some desirable characteristics that chemical control agents should possess include the following: They should be rapidly effective in low concentrations, -cidal to a wide range of microbes yet nontoxic to human and animal tissue, soluble in water or alcohol, inexpensive, noncorrosive to metals and plastics, demonstrate persistent or cumulative activity, and be stable and effective in the presence of organic matter.

Question 103

Choose the microbial control method that neither inhibits nor kills microbes, but instead physically removes them from liquids or air. Multiple Choice A) Irradiation B) Filtration C) Cold sterilization D) Lyophilization E) Desiccation

Answer 103

B) Filtration Explanation: Filtration is able to physically remove microbes from liquids and from air. There are filters with pores tiny enough to prevent the passage of viruses and thus are able to sterilize solutions or air that is passed through them.

Question 104

Archaea Multiple Choice A) lack peptidoglycan in their cell walls. B) cannot cause disease in humans. C) are most genetically related to bacteria. D) contain a nucleus.

Answer 104

A) lack peptidoglycan in their cell walls.

Question 105

The specific sequence of 3 bases in mRNA that encodes a particular amino acid is the _________blank whereas the complementary sequence of 3 bases in tRNA that bind to the mRNA is known as the _________blank. Multiple Choice A) gene; locus B) codon; anticodon C) 5' cap; 3' poly A tail D) primer; telomere

Answer 105

B) codon; anticodon Explanation: The specific sequence of 3 bases in mRNA that encodes a particular amino acid is the codon. The sequence of 3 complementary bases on tRNA that binds to the codon temporarily during translation is known as the anticodon. This complementary matching of the codon and anticodon is what ensures the correct amino acid is delivered to the chain based on the code in mRNA.

Question 106

Select the mechanisms below which enable the horizontal transfer of antibiotic resistance genes. Check All That Apply A) Transformation B) Transduction C) Transcription D) Translation E) Conjugation

Answer 106

A) Transformation B) Transduction E) Conjugation Explanation: Antibiotic resistance genes can be spread by any of the horizontal gene transfer mechanisms used by bacteria which include transformation, transduction, and conjugation.

Question 107

Select the taxonomic division that includes the archaea (archaebacteria). Multiple Choice A) Temericutes B) Firmicutes C) Gracilicutes D) Mendosicutes

Answer 107

D) Mendosicutes Explanation: The archaea (archaebacteria) are classified in the Mendosicutes division which includes prokaryotic cells that have unusual cell walls, lack peptidoglycan, and have unusual nutritional habits.

Question 108

Order the following discoveries, from earliest to most recent events, to test your understanding of modern microbiological advances. A) Role of the human microbiome B) Importance of small RNAs C) CRISPR as a gene editing tool D) Invention of the PCR technique

Answer 108

D) Invention of the PCR technique B) Importance of small RNAs A) Role of the human microbiome C) CRISPR as a gene editing tool Explanation: PCR techniques came into use in the 1980s, and the importance of small RNAs became apparent in the 2000s. In 2012, early findings about the role of the human microbiome were released. In 2013, scientists used CRISPR in gene editing.

Question 109

Which of the following contributes to healthcare-associated infections? Multiple Choice A) Susceptible population B) Hospital environment C) Other patients D) Patient's own normal microbiota E) All of the choices are correct.

Answer 109

E) All of the choices are correct.

Question 110

Select the microorganism that is least resistant to chemical and physical control measures. Multiple Choice A) Non-enveloped (naked) viruses B) Gram-negative bacteria C) Protozoan cysts D) Enveloped viruses E) Gram-positive bacteria

Answer 110

D) Enveloped viruses Explanation: Microorganisms vary considerably in their susceptibility to chemical and physical control agents. The least resistant microorganisms are the enveloped viruses, since chemical and physical means readily disrupt the envelope and destroy the infectivity of the virus.

Question 111

There are many more antiviral drugs available on the market to treat viral infections than the number of antibiotic drugs available to treat bacterial infections today. A) True B) False

Answer 111

B) False Explanation: Antibiotic drugs far outnumber antiviral drugs today, due to the greater variety of targets available against bacterial pathogens. Because viruses are intracellular pathogens, antiviral medications can have severe side effects on host cells. Therefore, more effort is put into prevention methods such as vaccination development.

Question 112

Which structure plays a direct role in the exchange of genetic material between bacterial cells? Multiple Choice A) Fimbria B) Pilus C) Capsule D) Flagellum

Answer 112

B) Pilus

Question 113

Diffusion of water through a selectively permeable membrane is referred to as: Multiple Choice A) osmosis. B) pinocytosis. C) active transport. D) exocytosis.

Answer 113

A) osmosis. Explanation: Osmosis is a special category of diffusion, specifically referring to the diffusion of water through a selectively permeable membrane.

Question 114

Antibody production by B cells is considered a nonspecific immune function. A) True B) False

Answer 114

B) False Explanation: This is false. Antibodies are a specific immune defense mechanism, with each antibody targeting a specific antigen.

Question 115

Variations in the size and shape of cells within a single species of bacteria is known as Multiple Choice A) plasticity. B) pleiotropism. C) hermaphrodism. D) pleomorphism.

Answer 115

D) pleomorphism. Explanation: Pleomorphism is a term used to describe cell morphology when there is a variety of sizes, shapes, and arrangements among cells of a single bacterial species.

Question 116

Choose the phase of the bacterial growth curve during which a bacterial population has the shortest doubling time. Multiple Choice A) Death phase B) Lag phase C) Exponential growth phase D) Stationary growth phase

Answer 116

C) Exponential growth phase Explanation: A bacterial population would have its shortest doubling time when it is growing at its most rapid rate, which would occur during the exponential growth phase.

Question 117

Culturing of viruses can occur using _________blank methods such as live animal inoculation. Multiple Choice A) in vivo B) ex vivo C) in situ D) in vitro

Answer 117

A) in vivo Explanation: In vivo methods include live animal inoculations.

Question 118

Match the name of the taxonomic division with its description. A) Mendosicutes B) Tenericutes C) Gracilicutes D) Firmicutes Match each of the options above to the items below. 1) Gram-negative cell walls 2) Gram-positive cell walls 3) Lack cell walls 4) Unusual cell walls and nutritional habits

Answer 118

A) Mendosicutes 3) Lack cell walls B) Tenericutes 4) Unusual cell walls and nutritional habits C) Gracilicutes 2) Gram-positive cell walls D) Firmicutes 1) Gram-negative cell walls Explanation: The Gracilicutes include bacteria that have a gram-negative cell wall. The Firmicutes include bacteria that have a gram-positive cell wall. The Tenericutes include bacteria that lack a cell wall. The Mendosicutes have very different cells walls and nutritional habits. The Mendosicutes are also known as the Archaea, and today are classified in the Domain Archaea, quite distinct from the Domain Bacteria.

Question 119

Select the statement that accurately reflects the characteristics of viral capsids. Multiple Choice A) They are constructed of identical centromeres. B) They are made of lipids. C) Animal viruses exhibit helical or icosahedral capsids. D) Together with the viral envelope, it forms the nucleocapsid.

Answer 119

C) Animal viruses exhibit helical or icosahedral capsids. Explanation: Viral capsids are made up of proteins and are constructed of repeating units called capsomers. Together with the nucleic acid in the virus, it forms the nucleocapsid.

Question 120

Select the nonspecific processes below to test your understanding of the various categories of nonspecific immunity. Check All That Apply A) Inflammatory response B) Complement cascade C) Phagocytosis D) Interferon production E) Antibody production

Answer 120

A) Inflammatory response B) Complement cascade C) Phagocytosis D) Interferon production Explanation: The mechanisms that play important roles in nonspecific immunity include the inflammatory response, the complement cascade, phagocytosis, and interferon production. Antibodies are involved in the acquired specific response of the third line of defense.

Question 121

Choose the statement that best describes the benefits of microbial antagonism to the human host. Multiple Choice A) Microbial antagonism refers to the effects that antibiotics have on the normal microbiota. B) Microbial antagonism refers to the mechanisms by which a pathogen damages the host. C) Microbial antagonism occurs when members of the normal microbiota prevent pathogens from colonizing and becoming established in the body. D) Microbial antagonism refers to the effects that the human immune system has on the normal microbiota. E) Microbial antagonism keeps normal microbiota from colonizing some parts of the human body.

Answer 121

C) Microbial antagonism occurs when members of the normal microbiota prevent pathogens from colonizing and becoming established in the body. Explanation: Human normal microbiota often prevent pathogenic organisms from colonizing body sites. They do this by out-competing the pathogens for attachment sites and nutrients, and by secreting substances that specifically inhibit other bacteria. Basically, the members of the normal microbiota are “looking out for themselves,” but the human host benefits in the process. An example involves Clostridium difficile (C. diff) that lives in the guts of even healthy individuals but the numbers are kept in check by antagonism from normal microbiota of the gut. If the normal microbiota are disrupted, such as with broad-spectrum or long-term antibiotic use, C. diff can proliferate and cause intestinal disease.

Question 122

The first organisms on earth were: Multiple Choice A) multicellular. B) anoxygenic. C) sponges. D) oxygenic.

Answer 122

B) anoxygenic.

Question 123

Which of the following infections are caused by viruses? Check All That Apply A) Influenza B) Pertussis C) Chickenpox D) Warts E) Herpes F) Tuberculosis G) Measles H) Cholera

Answer 123

A) Influenza C) Chickenpox D) Warts E) Herpes G) Measles

Question 124

Resident microbiota can cause disease in some individuals if they gain access to the correct portal of entry. A) True B) False

Answer 124

A) True Explanation: True, endogenous microbes can still cause disease, especially in immunocompromised individuals. Even in healthy individuals, endogenous microbes can cause disease if they invade a different tissue of the body where they can multiply and cause damaging effects. One example is E. coli that colonizes the colon, but can be transmitted to the urinary tract through poor sanitary practices and cause a urinary tract infection (UTI).

Question 125

Contact dermatitis involves: Multiple Choice A) a sensitizing and provocative dose. B) an allergen entering the skin. C) T lymphocytes secreting inflammatory cytokines. D) the production of itchy papules and blisters. E) All of the choices are correct.

Answer 125

E) All of the choices are correct.

Question 126

The 0 quantifies the capacity of an infectious agent to spread; a R0 of 4.0 in a specified population indicates that one infected person can spread the disease to 4 others. A) True B) False

Answer 126

A) True

Question 127

A bacterial species is equivalent to that of an animal species because both exhibit a common form of sexual reproduction. A) True B) False

Answer 127

B) False Explanation: This is false. Bacteria do not undergo true sexual reproduction, but they can actually accept genetic material from unrelated microbes.

Question 128

Similar to macrophages, _________blank cells are products of the monocytic cell line that reside throughout the tissues and present antigen to lymphocytes. Multiple Choice A) T B) platelet C) dendritic D) neutrophil

Answer 128

C) dendritic Explanation: Dendritic cells are also derived from monoblasts and, like macrophages, function as antigen presenters in the lymph nodes and spleen.

Question 129

Select three of the most prevalent types of healthcare-associated infections. Check All That Apply A) Surgical site infections B) Skin infections C) Urinary tract infections D) Respiratory infections E) Reproductive tract infections

Answer 129

A) Surgical site infections C) Urinary tract infections D) Respiratory infections Explanation: Three of the four most prevalent types of healthcare-associated infections are (1) catheter-associated urinary tract infections, (2) surgical site infections, and (3) ventilator-associated respiratory infections.

Question 130

Aerobic respiration produces more ATP in bacteria than anaerobic respiration in eukaryotes. A) True B) False

Answer 130

A) True Explanation: This is true. Aerobic respiration, whether in bacteria or eukaryotes, always produces more ATP than anaerobic respiration.

Question 131

Any heightened immune response resulting in tissue damage is called a/an Multiple Choice A) hypersensitivity. B) autoimmune disease. C) transfusion reaction. D) immunodeficiency. E) desensitization.

Answer 131

A) hypersensitivity.

Question 132

Choose the phrase that describes MHC class I molecules. Multiple Choice A) Are proteins involved in the complement system B) Found on only some types of white blood cells C) Expressed on all human nucleated cells D) Are secreted from all human nucleated cells

Answer 132

C) Expressed on all human nucleated cells Explanation: Class I MHC genes code for glycoprotein markers that appear on all nucleated cells.

Question 133

Select the phrase that describes the antimicrobial activity of alcohols. Multiple Choice A) Disrupt membrane lipids and denature proteins B) Interfere with nucleic acid replication and transcription C) Disrupt peptidoglycan structure D) Destruction of endospores

Answer 133

A) Disrupt membrane lipids and denature proteins Explanation: Alcohols disrupt membrane lipids, interfere significantly with membrane function, and denature proteins.

Question 134

Mercury is a heavy metal that today is increasingly incorporated into plastic, steel, and textiles to create antimicrobial surfaces and clothing. A) True B) False

Answer 134

B) False Explanation: This is false. Silver is the heavy metal used for this activity today.

Question 135

Which of the following is not an example of a subunit vaccine? Multiple Choice A) Inactivated viruses B) Bacterial toxins synthesized chemically in the laboratory C) Products made by genetic engineering D) Molecules obtained from cultures of microbes

Answer 135

A) Inactivated viruses Explanation: Vaccine preparations can be broadly categorized as either whole organism (cells or viruses) or subcellular (subunit) preparations. Whole microbe preparations can be either live or attenuated. Vaccines that contain subunits or antigens from microbes can consist of subunits 1) isolated from the microbe, 2) chemically synthesized in the lab, or 3) made using genetic engineering techniques.

Question 136

Select the characteristic exhibited by viruses. Multiple Choice A) Composed of DNA and RNA B) Parasitic particles C) Independent living cellular organisms D) Lack a protein coat E) Much more complex than cells

Answer 136

B) Parasitic particles Explanation: Viruses are considered to be obligate intracellular parasites, completely dependent on host cells. Their structure is much simpler than cells. Viruses contain DNA or RNA but never both, wrapped in a protein coat called a capsid.

Question 137

Specific immune globulin (SIG) can be obtained from recovering patients and used for immunotherapy (artificial passive immunity). A) True B) False

Answer 137

A) True Explanation: True, SIG is a preferable preparation for immunotherapy because of its higher antibody titer from a defined smaller group of donors.

Question 138

Select the statement that explains the newer version of the “central dogma.” Multiple Choice A) While information primarily flows from DNA to RNA to protein, some information from RNA flows back to DNA in a regulatory role. B) Information flows one way from protein to RNA to DNA. C) Information originates in RNA and flows both to proteins and DNA. D) Information flows from DNA to RNA and from DNA directly to protein to regulate the activity of the proteins.

Answer 138

A) While information primarily flows from DNA to RNA to protein, some information from RNA flows back to DNA in a regulatory role. Explanation: The original “central dogma” stated that the flow of genetic information is one way, from DNA to RNA to protein. The newer version indicates that while most information flows from DNA to RNA to protein, some RNAs play a regulatory role when some information flows from RNA to DNA to regulate transcription.

Question 139

Select the statements that accurately describe antigens. Check All That Apply A) They are perceived as foreign. B) Only whole microbes can serve as antigens. C) Proteins are immunogenic antigens. D) Antigens provoke an immune response.

Answer 139

A) They are perceived as foreign. C) Proteins are immunogenic antigens. D) Antigens provoke an immune response. Explanation: Antigens, which can be proteins, provoke an immune response because they are perceived as foreign.

Question 140

The fundamental element of life is considered to be _________ as a result of its superior bonding capabilities. Multiple Choice A) nitrogen B) oxygen C) magnesium phosphate D) carbon

Answer 140

D) carbon

Question 141

Which of these organisms do not contain DNA? Multiple Choice A) Fungi B) Bacteria C) Prions D) Helminths

Answer 141

C) Prions

Question 142

Photosynthetic microorganisms contribute more oxygen to the atmosphere than plants. A) True B) False

Answer 142

A) True Explanation: Photosynthetic microorganisms (bacteria and algae) produce the majority of oxygen found in the atmosphere and are responsible for more than 70% of photosynthesis on earth.

Question 143

The movement of bacteria either toward or away from a chemical stimulus is referred to as Multiple Choice A) chemotaxis. B) phototropism. C) hydrotaxis. D) phototaxis.

Answer 143

A) chemotaxis. Explanation: The movement of bacteria toward or away from a chemical stimulus is chemotaxis. If the movement is toward a nutrient, it is called positive chemotaxis. If the movement is away from a repellent, it is called negative chemotaxis. Bacteria can also exhibit phototaxis, the movement to or away from light.

Question 144

Choose the statement that best describes the primary action of B cells. Multiple Choice A) B cells interact with antigen on antigen presenting cells. B) B cells divide and differentiate forming plasma cells that secrete antibodies. C) B cells produce interleukin-2, a lymphocyte growth factor. D) B cells become active in cell-mediated immunity.

Answer 144

B) B cells divide and differentiate forming plasma cells that secrete antibodies. Explanation: The consequence of antigen activation of B cells is the differentiation into plasma cells which secrete antibodies with the same specificity as the original receptor into the surrounding tissues.

Question 145

A/An _________blank is a group of bacterial genes in a linear arrangement that will be transcribed together. Multiple Choice A) operon B) centromere C) variable region D) repressor

Answer 145

A) operon Explanation: An operon is a group of genes in a linear arrangement that will be transcribed together. This group is controlled by a single promoter and operator sequence.

Question 146

What is the holobiont? Multiple Choice A) The human body B) The resident microbiota C) Both of these are considered the holobiont.

Answer 146

C) Both of these are considered the holobiont. Explanation: Because of the importance of the microbiome to human biology, a new term was developed. This relationship is symbiotic, with each participant being a symbiont. So, together, scientists call the resident microbiota and the human body the holobiont.

Question 147

Select the patterns of direct (contact) transmission of infectious disease. Check All That Apply A) Food, water B) Kissing, touching C) Fomites D) Droplets from sneezing/coughing E) Air F) Skin punctures (intentional or unintentional)

Answer 147

B) Kissing, touching D) Droplets from sneezing/coughing Explanation: Transmission of microbes can be accomplished by several routes, direct or indirect. The direct transmission patterns include kissing/touching, sexual transmission, and droplet transmission (as opposed to droplet nuclei where the transmission covers a greater distance). Some include vector transmission as a type of direct transmission as well.

Question 148

Choose the method used to sterilize an inoculation loop used in lab for culturing bacteria. Multiple Choice A) Radiation B) Hot air C) Incineration D) Autoclaving E) Pasteurization

Answer 148

C) Incineration Explanation: Loops are typically sterilized by holding the loop in the flame of a Bunsen burner or inside an electric incinerator. In either case, this uses dry heat and is a form of incineration.

Question 149

DNA replication is described as Multiple Choice A) dispersive. B) disruptive. C) semiconservative. D) conservative.

Answer 149

C) semiconservative. Explanation: DNA replication is semiconservative, where each parent strand serves as a template for the formation of a duplicate strand of DNA. The resulting double-stranded DNA molecules will each contain one original and one new strand.

Question 150

Select the bacterial appendage(s) that enables bacteria to stick to one another, to inanimate surfaces, and to host cells. Multiple Choice A) Fimbriae B) Pili C) Axial filaments D) Flagella E) Cell wall

Answer 150

A) Fimbriae Explanation: Bacterial fimbriae enable bacterial cells to aggregate by sticking to each other and surfaces, potentially leading to the formation of biofilms. In some cases, fimbriae are required structures for pathogenic bacteria; without them, the bacteria cannot cause infection.

Question 151

RNA plays an important role in what biological process? Multiple Choice A) Water transport B) Protein synthesis C) Replication D) Lipid metabolism

Answer 151

B) Protein synthesis

Question 152

Select the statement that most accurately reflects fever. Multiple Choice A) It enhances the availability of iron to microbes, killing them. B) It is a specific immune response to mostly viral infections. C) It enhances the rate of replication of many temperature-sensitive microbes. D) Fever enhances metabolism and protective mechanisms in the host.

Answer 152

D) Fever enhances metabolism and protective mechanisms in the host. Explanation: Fever benefits the host protective mechanisms, while inhibiting pathogens' growth and nutrition.

Question 153

Match the description with the name of the chemical bond. A) Covalent bond B) Hydrogen bond C) Ionic bond D) Van der Waals forces Match each of the options above to the items below. 1) A chemical bond in which electrons are transferred from one atom to another 2) A chemical bond in which electrons are shared by two atoms 3) A weak bond formed between a hydrogen bonded to one molecule and an oxygen or nitrogen atom on the same molecule or a different molecule 4) Weak attractions between molecules with low levels of polarity

Answer 153

A) Covalent bond 3) A weak bond formed between a hydrogen bonded to one molecule and an oxygen or nitrogen atom on the same molecule or a different molecule B) Hydrogen bond 1) A chemical bond in which electrons are transferred from one atom to another C) Ionic bond 2) A chemical bond in which electrons are shared by two atoms D) Van der Waals forces 4) Weak attractions between molecules with low levels of polarity Explanation: Ionic bonds are strong bonds between two atoms in which one atom transfers an electron to another atom. Covalent bonds are formed between atoms that share electrons. Hydrogen bonds are weak bonds that form between two atoms in which a hydrogen atom covalently bonded to one molecule is attracted to an oxygen or nitrogen in a different molecule or in another part of the same molecule. Van der Waals forces are weak attractive forces between molecules of low polarity.

Question 154

Select the patterns of indirect (vehicle) transmission of infectious disease. Check All That Apply A) Food, water B) Kissing, touching C) Fomites D) Air E) Droplets F) Soil

Answer 154

A) Food, water C) Fomites D) Air F) Soil Explanation: Indirect transmission requires a nonliving intermediate (vehicle) to "deliver" the infectious agent from one host to another. Examples include air, water, food, soil, and inanimate objects known as fomites.

Question 155

Select the term that best describes any organism that contains and expresses genes that originated in another organism. Multiple Choice A) Polymerized B) Synthetic C) Genetically modified D) Recombinant

Answer 155

D) Recombinant Explanation: These are referred to as recombinant organisms, some of which may be genetically-modified.

Question 156

Select the components that comprise the first line defense mechanisms. Check All That Apply A) Physical barriers B) Complement C) Chemical defenses such as lysozyme and HCl D) Inflammation E) Resident microbiota F) Body functions such as sneezing, urinating, coughing, and vomiting

Answer 156

A) Physical barriers C) Chemical defenses such as lysozyme and HCl E) Resident microbiota F) Body functions such as sneezing, urinating, coughing, and vomiting Explanation: Barriers at the portal of entry comprise the first line of defense and are divided into physical barriers, chemical defenses on the skin and mucous membranes, and "flushing" body functions such as coughing and sneezing. Recent research also suggests that the resident microbiota provides microbial antagonism, blocking space and nutrients from pathogens.

Question 157

Anabolic reactions produce ATP to create new molecules. A) True B) False

Answer 157

B) False Explanation: This is false. Anabolic reactions use ATP to make new molecules.

Question 158

Select all of the statements that illustrate advantages of live, attenuated vaccines. Check All That Apply A) Viable attenuated microbes can still multiply, inducing robust immune responses. B) They enhance herd immunity because they produce long lasting protection due to the memory response. C) They require special storage facilities. D) They can revert to a more virulent form due to mutation. E) They can be spread to non-immune individuals.

Answer 158

A) Viable attenuated microbes can still multiply, inducing robust immune responses. B) They enhance herd immunity because they produce long lasting protection due to the memory response. Explanation: The advantages of live preparations include the fact that viable organisms can multiply, thus inducing both humoral and cell-mediated responses along with a long lasting memory response. Due to the fact that the microbe multiplies, usually only one dose of the vaccine is needed. Disadvantages include the need for special storage facilities, the potential for mutation to a more virulent form, and the potential for transmission of the attenuated microbe to others.

Question 159

Superantigens are potent stimulators of what cell type? Multiple Choice A) Monocytes B) Dendritic cells C) T cells D) B cells

Answer 159

C) T cells Explanation: Superantigens are potent stimulators of T cells. If present in an infection, T cells are activated at rates 100 times greater than with normal antigens. The release of cytokines that results can be extremely damaging to the host.

Question 160

A dramatic increase in the incidence of a specific disease in a given population is referred to as a/an: Multiple Choice A) pandemic. B) endemic. C) outburst. D) mortality. E) epidemic.

Answer 160

E) epidemic.

Question 161

Antibiosis is a form of: Multiple Choice A) parasitism. B) opportunism. C) antagonism. D) synergism.

Answer 161

C) antagonism. Explanation: Antibiosis is a form of microbial antagonism. In this nonsymbiotic association, one organism produces an inhibitory chemical such as an antibiotic, giving it a competitive advantage in the community.

Question 162

Select the methods that illustrate the use of moist heat to control microbes. Check All That Apply A) Steam autoclave B) Incineration C) Pasteurization D) Desiccation E) Boiling water

Answer 162

A) Steam autoclave C) Pasteurization E) Boiling water Explanation: Methods using moist heat include boiling water, pasteurization, and the autoclave (steam under pressure). Incineration is a dry heat method, and desiccation is not a heat method, but instead involves drying or water removal.

Question 163

UNDER CONSTRUCTION. I NEED TO FIGURE OUT HOW TO DO ITALICS Which of the following choices is a correct way to type the binomial name of a microorganism? A) staphylococcus aureus B) staphylococcus Aureus C) Staphylococcus aureus D) Staphylococcus aureus E) Staphylococcus Aureus

Answer 163

D) Staphylococcus aureus Explanation: The binomial, or scientific name, of a microorganism includes the genus name followed by the species name. It must be typed in italics or underlined if handwritten. In addition, the first letter of the genus must be capitalized while the first letter of the species name is lowercase.

Question 164

Select all of the statements that characterize obligate saprobes. Check All That Apply A) They live in a host. B) They live on a host. C) They feed off of dead organic matter in water D) They feed off of dead organic matter in soil. E) They lack enzymes to degrade organic matter.

Answer 164

C) They feed off of dead organic matter in water D) They feed off of dead organic matter in soil. Explanation: Obligate saprobes must live off of dead organic matter in soil or water, and they cannot adapt to a host.

Question 165

Select characteristics exhibited by exotoxins, but not exhibited by endotoxins. Check All That Apply A) Composed of lipopolysaccharide B) Require very small doses to cause toxic effects C) Secreted from a living cell D) Heat-stable E) Have very specific targets F) Fever-inducing

Answer 165

B) Require very small doses to cause toxic effects C) Secreted from a living cell E) Have very specific targets Explanation: Bacterial exotoxins are composed of protein and are toxic in very small doses. They are actively secreted by living cells and have very specific targets in the host organism. Generally, they do not cause fever. Due to their protein composition, they are not heat-stable, and are denatured by temperatures of 60°C and higher.Bacterial exotoxins are composed of protein and are toxic in very small doses. They are actively secreted by living cells and have very specific targets in the host organism. Generally, they do not cause fever. Due to their protein composition, they are not heat-stable, and are denatured by temperatures of 60°C and higher.Bacterial exotoxins are composed of protein and are toxic in very small doses. They are actively secreted by living cells and have very specific targets in the host organism. Generally, they do not cause fever. Due to their protein composition, they are not heat-stable, and are denatured by temperatures of 60°C and higher.Bacterial exotoxins are composed of protein and are toxic in very small doses. They are actively secreted by living cells and have very specific targets in the host organism. Generally, they do not cause fever. Due to their protein composition, they are not heat-stable, and are denatured by temperatures of 60°C and higher.Bacterial exotoxins are composed of protein and are toxic in very small doses. They are actively secreted by living cells and have very specific targets in the host organism. Generally, they do not cause fever. Due to their protein composition, they are not heat-stable, and are denatured by temperatures of 60°C and higher. Bacterial exotoxins are composed of protein and are toxic in very small doses. They are actively secreted by living cells and have very specific targets in the host organism. Generally, they do not cause fever. Due to their protein composition, they are not heat-stable, and are denatured by temperatures of 60°C and higher.

Question 166

When the product of a metabolic pathway accumulates, it may be able to slow down or turn off the pathway by inhibiting the activity of an enzyme that catalyzes an early step in the pathway. This is referred to as: Multiple Choice A) competitive inhibition. B) allosteric inhibition. C) negative feedback.

Answer 166

C) negative feedback. Explanation: When the product of a pathway accumulates and inhibits the activity of an enzyme that functions early in the pathway, this is a negative feedback mechanism. These are usually noncompetitive inhibitors.

Question 167

Select all of the statements which provide reasons why it is controversial and difficult to assign species names to viruses. Check All That Apply A) Some scientists argue that viruses are non-organisms and therefore can’t be given species names. B) Viral genetics are poorly understood. C) Viruses don’t possess ribosomal RNA. D) Viruses are too changeable.

Answer 167

A) Some scientists argue that viruses are non-organisms and therefore can’t be given species names. D) Viruses are too changeable. Explanation: While most scientists agree on classifying viruses into orders, families, and genera, the concept of viral “species” has been controversial. Some scientists argue that viruses aren’t truly living things, that they are “non-organisms” and therefore can’t be speciated. Also, viruses change readily and characteristics that might be used for speciation might change over time.

Question 168

Select the three methods that are used to cultivate viruses. Check All That Apply A) Use of cell culture techniques B) Use of enriched agar media C) Use of animal inoculation D) Inoculation of eggs that contain embryos E) Use of enriched broth media

Answer 168

A) Use of cell culture techniques C) Use of animal inoculation D) Inoculation of eggs that contain embryos Explanation: Because of their need for a host cell, viral cultivation requires different measures than those used to cultivate bacteria or eukaryotic pathogens. The three primary ways that viruses are cultivated include (1) inoculation of animals, (2) inoculation of embryonated eggs, and (3) inoculation of cell cultures.

Question 169

When an infectious disease cannot spread in a population because it lacks a significant number of susceptible hosts, the phenomenon is referred to as: Multiple Choice A) passive immunity. B) herd immunity. C) protective immunity. D) active immunity. E) a protected population.

Answer 169

B) herd immunity.

Question 170

There is evidence to support that some diseases, such as cardiovascular disease, may be linked to chronic inflammation in the body. A) True B) False

Answer 170

A) True Explanation: It is recognized that chronic inflammation can have long-term damaging effects on tissues.

Question 171

Carbon, nitrogen, oxygen, and hydrogen are considered _________blank because they are required in relatively large quantities, whereas manganese, zinc, and copper are considered _________blank because they are required in very small quantities. Multiple Choice A) macronutrients; micronutrients B) nonessential; essential C) micromolecules; macromolecules D) elements; atoms

Answer 171

A) macronutrients; micronutrients Explanation: Essential nutrients can be divided into two classes depending on the relative quantities required by an organism. Macronutrients are nutrients that are required in relatively large quantities and include carbon, hydrogen, oxygen, and nitrogen. Micronutrients are required in very small quantities and there is a lengthy list of these, including manganese, zinc, and copper.

Question 172

Select the statements that are true of repressible operons to test your understanding of the differences between inducible and repressible operons. Check All That Apply A) Repressible operons often contain genes for enzymes that digest sugars. B) Repressible operons are usually the “turned on” state and are “turned off” when their product is in adequate supply. C) The product of the enzymes in the operon functions as a corepressor. D) Repressible operons will be “turned on” in the presence of the product and turned off in its absence. E) Enzymes necessary for the synthesis of amino acids are often encoded by genes in repressible operons.

Answer 172

B) Repressible operons are usually the “turned on” state and are “turned off” when their product is in adequate supply. C) The product of the enzymes in the operon functions as a corepressor. E) Enzymes necessary for the synthesis of amino acids are often encoded by genes in repressible operons. Explanation: Repressible operons often encode genes involved in biosynthetic pathways, such as the pathways needed to synthesize amino acids. The operons are usually in the “on” position. When an adequate supply of the product of the enzymes in the operon is present in the cell, this product will act as a corepressor needed to block the transcription of the operon. Thus the product turns off the operon.

Question 173

Select which line of defense exhibits specificity. Multiple Choice A) Third B) Fourth C) Second D) First

Answer 173

A) Third Explanation: Only the third line of defense exhibits specificity with lymphocytes that target specific antigens; there is no fourth line of defense.

Question 174

Medicine focuses on the _________blank whereas epidemiology focuses on the _________blank. Multiple Choice A) group; individual B) individual; group C) specific; general D) general; specific

Answer 174

B) individual; group

Question 175

Colonization will result in infection and disease if any pathogenic microbes are present. A) True B) False

Answer 175

B) False Explanation: Potential pathogens can simply exit the body without multiplying and causing infection.

Question 176

Which of the following processes can be the result of human manipulation of microbial genes? Multiple Choice A) Natural selection B) Bioremediation C) Central dogma D) Abiogenesis

Answer 176

B) Bioremediation

Question 177

Select the characteristics of T lymphocytes, which are involved in specific immunity. Check All That Apply A) Mature in the bone marrow B) Mature in the thymus C) Move freely among lymphoid tissues and connective tissue D) Responsible for cell-mediated immunity E) Form specialized plasma cells that produce antibodies

Answer 177

B) Mature in the thymus C) Move freely among lymphoid tissues and connective tissue D) Responsible for cell-mediated immunity Explanation: T lymphocytes mature in the thymus and then are released to move freely through various tissues where they are responsible for cell-mediated immunity.

Question 178

Which of the following is used to store energy in cells? Multiple Choice A) Protein B) DNA C) ATP D) RNA

Answer 178

C) ATP

Question 179

Nanotubes are extensions of the _________ that can function in _________. Multiple Choice A) membrane; nutrient transfer B) flagellum; motility C) pilus; genetic exchange D) membrane; genetic exchange

Answer 179

A) membrane; nutrient transfer

Question 180

A/An _________blank agent would be used to destroy bacteria on a countertop whereas a/an _________blank agent would be used on skin prior to making an incision. Multiple Choice A) disinfectant; antiseptic B) disinfectant; sterilant C) antiseptic; disinfectant D) antiseptic; sterilant

Answer 180

A) disinfectant; antiseptic Explanation: Since a countertop is an inanimate surface, a disinfectant would be used to remove or destroy bacteria. Skin is living tissue, so an antiseptic would be used to remove or kill bacteria prior to making an incision.

Question 181

Which of the following is an acellular microbe lacking a nucleus? Multiple Choice A) Virus B) Bacterium C) Helminth D) Protozoan

Answer 181

A) Virus

Question 182

Choose the phrase that describes what will happen to pH as hydrogen ion concentration increases. Multiple Choice A) pH will not change B) pH will decrease C) pH will increase

Answer 182

B) pH will decrease Explanation: As hydrogen ion concentration increases, the pH will decrease. The higher the hydrogen ion concentration is in a solution, the lower the pH and the more acidic a solution will be.

Question 183

DNA leads to RNA, which can lead to the creation of: Multiple Choice A) oxygen. B) cells. C) lipids. D) proteins.

Answer 183

D) proteins.

Question 184

Order the following choices to reflect the organization of taxa, from the most general to the most specific, to test your understanding of levels of classification. A) Species B) Domain C) Phylum D) Order

Answer 184

B) Domain C) Phylum D) Order A) Species Explanation: Taxonomy is the formal system used to organize, classify, and name living things. The domain is the most general all-inclusive taxonomic category, followed by kingdom, phylum, class, order, family, genus and species. To remember this, think of this phrase "Dear King Phillip Came Over For Great Spaghetti" or come up with your own mnemonic device for remembering the proper ordering of the taxonomic classes.

Question 185

Which of these statements are true? Check All That Apply A) Norovirus, a non-enveloped enterovirus, is not affected by hand sanitizer. B) The envelope of the influenza virus is susceptible to the alcohol in hand sanitizer. C) Alcohols in hand sanitizer affect the capsid of viral particles. D) Alcohols in hand sanitizer affect the phospholipid bilayer of the viral envelope. E) Hand sanitizer is an effective means of inactivating all types of viruses.

Answer 185

A) Norovirus, a non-enveloped enterovirus, is not affected by hand sanitizer. B) The envelope of the influenza virus is susceptible to the alcohol in hand sanitizer. D) Alcohols in hand sanitizer affect the phospholipid bilayer of the viral envelope. Explanation: The alcohol in hand sanitizer disrupts the envelope of enveloped viruses, but does not affect the naked viruses.

Question 186

A majority of medically important microbes are classified as: Multiple Choice A) psychrophiles. B) endotherms. C) mesophiles. D) thermophiles.

Answer 186

C) mesophiles. Explanation: The majority of pathogens are mesophilic microbes, with optimal temperatures at or near body temperature.

Question 187

When a hypothesis has been thoroughly supported by long-term study and data, it is considered Multiple Choice A) a law. B) speculation. C) proven. D) a theory.

Answer 187

D) a theory

Question 188

Select the types of RNA that are directly involved in translation. Check All That Apply A) tRNA B) rRNA C) xRNA D) mRNA E) Antisense RNA

Answer 188

A) tRNA B) rRNA D) mRNA Explanation: The three types of RNA involved in translation are messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).

Question 189

Which of the following is a microorganism that contains organelles? Multiple Choice A) Prion B) Fungus C) Bacterium D) Virus

Answer 189

B) Fungus

Question 190

The mononuclear phagocyte system is an intricate passageway within and between tissues and organs and is an area full of lymphocytes, which are phagocytic cells used to attack foreign invaders. A) True B) False

Answer 190

B) False Explanation: The MPS is rich in phagocytic cells such as macrophages which are available to attack foreign intruders in the body.

Question 191

Select statements that apply to B cell maturation. Check All That Apply A) B cells form and mature in the bone marrow. B) B cells form in the bone marrow and mature in the thymus. C) Each B cell receives a specific antigen receptor, an immunoglobulin molecule. D) Hormones guide the maturation process. E) B cells become responsive to MHC molecules.

Answer 191

A) B cells form and mature in the bone marrow. C) Each B cell receives a specific antigen receptor, an immunoglobulin molecule. Explanation: B cells mature in the bone marrow under the influence of chemical signals from resident stromal cells. Each one is equipped with its own unique immunoglobulin receptor for a specific antigen.

Question 192

A systemic, sometimes fatal, reaction with airway obstruction and circulatory collapse is: Multiple Choice A) antibody-mediated. B) T-cell-mediated. C) atopic. D) delayed. E) systemic anaphylaxis.

Answer 192

E) systemic anaphylaxis.

Question 193

Select the targets of TC cells. Check All That Apply A) Virally infected cells B) Cancer cells C) NK cells D) Cells transplanted from other animals or humans E) Bacterial cell walls

Answer 193

A) Virally infected cells B) Cancer cells D) Cells transplanted from other animals or humans Explanation: Cytotoxic T cells target cancer cells, virally infected cells, and cells from animals or other humans.

Question 194

Innate, physical barriers of host defenses: Check All That Apply A) include the skin. B) include the mucous membranes. C) all contain keratin which makes the barriers highly impervious. D) are part of the second line of host defenses. E) are all covered with mucus that adds another layer of protection.

Answer 194

A) include the skin. B) include the mucous membranes. Explanation: The skin and mucous membranes comprise the innate physical barriers of the first line defenses. Skin epithelia contain keratin which helps make it impervious, and mucous membranes are coated with mucus which traps foreign agents.

Question 195

Please choose the best definition of virulence factors. Multiple Choice A) Characteristics of a microorganism, such as its Gram stain morphology, types of media it grows on, and colony morphology B) The natural habitats of the microorganism or the sources from which a host can become infected C) Characteristics of a microorganism that enable it to establish infection and cause disease D) Factors that enable a microorganism to be resistant to antimicrobial medications E) The sites within a host in which a microorganism can reside and cause disease

Answer 195

C) Characteristics of a microorganism that enable it to establish infection and cause disease Explanation: Virulence factors are characteristics of a microorganism that enable it to establish infection and cause disease. Examples include toxin production, enzyme production, antiphagocytic factors, and epigenetic mechanisms.

Question 196

Choose the statement or characteristic that best describes the current taxonomic system. Multiple Choice A) First division is based on prokaryote vs eukaryote with all prokaryotes being very genetically distinct from the eukaryotes B) Three distinct cell types called domains as the highest taxonomic category C) Five kingdoms as the highest levels of taxonomy D) Organisms divided first into groups of plants, animals, and microorganisms

Answer 196

B) Three distinct cell types called domains as the highest taxonomic category Explanation: The current taxonomic system is comprised of 3 domains at the top: Bacteria (Eubacteria), Archaea (Archaeabacteria), and Eukarya. All arose from the same ancestral cell line, but Archaea are more genetically related to Eukarya than they are to Bacteria.

Question 197

If human red blood cells are placed in a vial of pure water Multiple Choice A) a hypertonic gradient is created. B) the net water movement is out of the cell. C) the net water movement is into the cell. D) an isotonic gradient is created.

Answer 197

C) the net water movement is into the cell. Explanation: Cellular cytoplasm is not 100% water, so this creates a hypotonic condition and results in a net movement of water into the cell over time.

Question 198

The genetic makeup of an organism is referred to as its _________blank whereas the observable traits due to gene expression are referred to as its _________blank. Multiple Choice A) haplotype; phenotype B) phenotype; genotype C) genotype; phenotype D) genotype; proteotype

Answer 198

C) genotype; phenotype Explanation: The genetic makeup of an organism is its genotype. The observable traits or characteristics of an organism constitute its phenotype. The phenotype is the result of the interaction of the genotype and the organism’s environment.