General Biology II Chapter 20

Question 1

What are noncellular infectious particles that consist of nucleic acid surrounded by capsid proteins and, in some cases, an envelope derived from membrane of its hosts?

Answer 1

A virus.

Question 2

What are the two main components that all viruses have in common?

Answer 2

Genetic material and protein coat.

Question 3

What is the specific type of virus that attacks ONLY bacterial cells?

Answer 3

Bacteriophages (sometimes called phages).

Question 4

What are all types of microbes capable of living in or on humans collectively known as?

Answer 4

Human microbiota.

Question 5

What is a disease causing microbe?

Answer 5

Pathogen.

Question 6

What is a free viral particle that is typically so small that it can only be seen with an electron microscope (about 25 to 300 nanometers in diameter).

Answer 6

A virion.

Question 7

What is an obligate intracellular parasite that has no metabolic machinery of its own and can multiply only inside living cells?

Answer 7

A virus.

Question 8

What is an enveloped virus that replicates inside human white blood cells?

Answer 8

HIV (Human Immunodeficiency Virus).

Question 9

What is a virus whose RNA genome is used as a template to produce double-stranded DNA inside a host cell?

Answer 9

A retrovirus.

Question 10

What is the swapping of genes between viruses that infect a host at the same time?

Answer 10

Viral reassortment.

Question 11

What is the outbreak of a disease in a limited region.

Answer 11

An epidemic.

Question 12

What is the outbreak of disease that simultaneously affects people throughout the world?

Answer 12

A pandemic.

Question 13

True or False?
Viruses can be transmitted from animals to humans.

Answer 13

True.

Question 14

True or False?
Viral pathogens cannot change by mutation or reassortment.

Answer 14

False.

Question 15

What is it when an individual acquires genes by a mechanism other than inheritance?

Answer 15

Horizontal gene transfers.

Question 16

What is it that occurs when a prokaryotic cell takes up DNA from its environment and integrates the DNA into its genome?

Answer 16

Transformation.

Question 17

What is it that occurs when bacteriophages move genes between cells?

Answer 17

Transduction.

Question 18

What involves movement of genes on a plasmid?

Answer 18

Conjugation.

Question 19

What is a small circle of double-stranded DNA separate from the chromosome?

Answer 19

A plasmid.

Question 20

True or False?
Prokaryotic cells reproduce asexually by binary fission.

Answer 20

True.

Question 21

True or False?
Horizontal gene transfers do not allow prokaryotes to acquire new genes.

Answer 21

False.

Question 22

True or False?
Both bacteria and archaea cells are typically walled and have a single chromosome that is not enclosed within a nucleus.

Answer 22

True.

Question 23

What is a resilient resting structure that consists of a stripped down, dehydrated bacterial cell within a thick protective covering?

Answer 23

An endospore.

Question 24

Which group of organisms are photosynthetic and use the energy of light to assemble organic compounds from CO2 and water?

Answer 24

Photoautotrophs.

Question 25

Which group of organisms consists of bacteria, archaea, photosynthetic protists, and plants?

Answer 25

Photoautotrophs.

Question 26

Which two groups of organisms consists of only bacteria and archaea?

Answer 26

Chemoautotrophs and photoheterotrophs.

Question 27

Which group of organisms consists of bacteria, archaea, fungi, animals, and nonphotosynthetic protists?

Answer 27

Chemoheterotrophs.

Question 28

Which group of organisms obtain energy by oxidizing (removing electrons from) inorganic molecules such as hydrogen sulfide and methane?

Answer 28

Chemoautotrophs.

Question 29

Which group of organisms bacteria and archaea are the main producers in dark environments such as the seafloor?

Answer 29

Chemoautotrophs.

Question 30

Which group of organisms harvest energy from light, and carbon from alcohols, fatty acids, or other small organic molecules?

Answer 30

Photoheterotrophs.

Question 31

Which group of organisms obtain both energy and carbon by breaking down carbohydrates, lipids, and proteins?

Answer 31

Chemoheterotrophs.

Question 32

Fill in the Blank: "Most bacteria and some archaea are _________________, as are fungi, animals, and nonphotosynthetic protists. All pathogenic bacteria are _________________ that extract organic compounds from their host."

Answer 32

Chemoheterotrophs.

Question 33

What break down the complex organic molecules in wastes and remains into inorganic components that plants can take up and use?

Answer 33

Decomposers.

Question 34

By which process do prokaryotes incorporate nitrogen from the air into ammonia (NH3)?

Answer 34

Nitrogen fixation.

Question 35

True or False? Bacteria and archaea are Earth's second most abundant organisms.

Answer 35

False. Bacteria and archaea are Earth's MOST abundant organisms.

Question 36

True or False? "Prokaryotes are metabolically diverse; they utilize all four modes of nutrition and may be aerobic or anaerobic."

Answer 36

True.

Question 37

True or False? "Only prokaryotes can carry out nitrogen fixation."

Answer 37

True.

Question 38

In which bacteria is the outermost layer of the cell a thick wall of peptidoglycan?

Answer 38

Gram-positive bacteria.

Question 39

What is a polymer of amino acids and sugars that is unique to bacteria?

Answer 39

Peptidoglycan.

Question 40

Fill in the blank: "Photosynthesis evolved in many bacterial lineages, but only _____________ utilize the noncyclic pathway and release free oxygen."

Answer 40

Cyanobacteria.

Question 41

What is to thank for nearly all the oxygen in the Earth's atmosphere?

Answer 41

Cyanobacteria and their chloroplast descendants.

Question 42

What is the largest and most diverse bacterial group that includes about a third of all known bacteria?

Answer 42

Proteobacteria.

Question 43

What is an extremely small bacteria that is shaped like a stretched-out spring?

Answer 43

Spirochetes.

Question 44

What is an extremely small bacteria that lives inside cells of vertebrates?

Answer 44

Chlamydias.

Question 45

True or False? "Bacteria benefit other organisms by putting oxygen into the air, fixing nitrogen, and aiding their host's digestion."

Answer 45

True.

Question 46

What are secreted proteins that bind to and directly harm our body cells?

Answer 46

Exotoxins.

Question 47

What are lipopolysaccharides integral to the outer membrane of Gram-negative bacteria? They are not secreted and are released when a bacterial cell dies and fragments. They are not directly harmful to host cells, but their presence elicits a host immune response.

Answer 47

Endotoxins.

Question 48

True or False? "All Gram-negative bacteria have endotoxins, but exotoxins are secreted by some Gram-negative bacteria and some Gram-positives."

Answer 48

True.

Question 49

True or False? "Antibiotics target the metabolic processes of pathogenic bacteria. Changes in bacterial structure or metabolism can lead to antibiotic resistance."

Answer 49

True.

Question 50

What is an organism that grows only at a very high temperature?

Answer 50

An extreme thermophile.

Question 51

What are organisms that live in highly salty water?

Answer 51

Extreme halophiles.

Question 52

Fill in the Blank: "Many archaea, including some extreme thermophiles and extreme halophiles, are ___________, or methane makers. These archaea are strict anaerobes, meaning they cannot live in the presence of oxygen."

Answer 52

Methanogens.

Question 53

True or False? "Archaea are single cells without a nucleus that are closer to eukaryotes than to bacteria. Many live in very hot or very salty habitats, but there are archaea nearly everywhere."

Answer 53

True.

Question 54

True or False? "Archaea are known to be human pathogens and foster the presence of pathogenic bacteria."

Answer 54

False. "NO archaea are known to be human pathogens, although some may foster the presence of pathogenic bacteria."

Question 55

What are small, circular, naked single-stranded RNAs that cause disease in many plants?

Answer 55

Viroids.