Exam 1

Question 1

Which is the correct usage of binomial nomenclature?

• Escherichia coli
• Escherichia coli
• escherichia coli
• Escherichia Coli
• E.coli

Answer 1

E.coli

Question 2

Who first observed prokaryotic microbes?

• Carolus Linnaeus
• Anton van Leeuwenhoek
• Robert Hooke
• Louis Pasteur
• Robert Koch

Answer 2

• Anton van Leeuwenhoek

Question 3

Which statement is not true?

• Microbes are used in producing fermentation products such as vinegar and alcoholic beverages.
• Microbes help recycling chemical elements between the soil, water, life, and air.
• Only microorganisms can fix nitrogen gas from the air.
• Many more microorganisms in nature are harmful than are beneficial.
• Some microbes in intestines are important for digestion and the synthesis of some vitamins.

Answer 3

• Many more microorganisms in nature are harmful than are beneficial.

Question 4

_____ observed the fruiting bodies, the reproductive structures of molds, and describe them in his book “Micrographia.”

• Louis Pasteur
• Anton van Leeuwenhoek
• Robert Hooke
• Carolus Linnaeus
• Robert Koch

Answer 4

• Robert Hooke

Question 5

Koch’s success in proving the germ theory of disease was mainly due to the development of ___.

• boiling jar
• sterile meat broth
• microscope
• aseptic technique
• pure culture

Answer 5

• pure culture

Question 6

Streptomycin is an example of _____ because it is produced by the soil microbe Streptomyces griseus.

• antimicrobial dyes
• synthetic drugs
• antibiotics
• magic bullets
• salvarsans

Answer 6

• antibiotics

Question 7

The process by which microbes turn grape juice into wine is called ________.

• respiration
• pasteurization
• sterilization
• fermentation
• vaccination

Answer 7

• fermentation

Question 8

Which of the following is NOT a domain in Woese phylogenetic tree?

• Bacteria
• Plantae
• Archaea
• Eukarya
• All of the above are domains in Woese phylogenetic tree.

Answer 8

• Plantae

Question 9

“Bacillus” in microbiology has more than one meaning. Which is NOT one of them?

• a bacterial shape.
• rod-shape.
• a specific genus.
• pleomorphic.
• “Bacillus” may mean all of the above.

Answer 9

• pleomorphic.

Question 10

Spherical bacterial cells in grape-like clusters would be referred to as a ______ arrangement.

• streptobacillus
• vibrio
• staphylococcus
• streptococcus
• spiral

Answer 10

• staphylococcus

Question 11

consider the substances that surround bacterial cells that are viscous polymer of polysaccharide, polypeptide, or both.

What is the general term for these substances?

• peptidoglycan
• cell wall
• glycocalyx
• biofilm
• outer shell

Answer 11

• glycocalyx

Question 12

consider the substances that surround bacterial cells that are viscous polymer of polysaccharide, polypeptide, or both.

Streptococcus mutans has ___ that is unorganized and loosely attached to the cell wall.

• biofilm
• fimbriae
• capsule
• outer membrane
• slime layer

Answer 12

• slime layer

Question 13

consider the substances that surround bacterial cells that are viscous polymer of polysaccharide, polypeptide, or both.

Which is NOT a function of these substances in bacteria?

• to protect pathogenic bacteria from phagocytosis by the host cells.
• to serve as an extracellular polymeric substance (EPS) in biofilm.
• to provide motility to the bacterial cells .
• to enable the bacterial cells to survive by attaching to various surfaces in their natural environment.
• all of the above are functions of these substances.

Answer 13

• to provide motility to the bacterial cells .

Question 14

Which of the following terms refers to a bacterial cell having a single flagellum at both ends?

• monotrichous
• amphitrichous
• atrichous
• lophotrichous
• peritrichous

Answer 14

• amphitrichous

Question 15

Proteus mirabilis moves across a surface by rotating flagella. This movement is called

• gliding motility.
• twitching motility.
• swimming.
• swarming.
• conjugative motility.

Answer 15

• swarming.

Question 16

In nature, antibiotic resistance among pathogenic bacteria can be spread by ____.

• flagella
• fimbria
• pili
• peptidoglycan
• pseudomurein

Answer 16

• pili

Question 17

In the name E. coli O157:H7, “H7” indicates an antigenic type of _____.

• core polysaccharide in the outer membrane
• flagella
• lipid A
• histone-like proteins
• H antigen

Answer 17

• flagella

Question 18

E. coli O157:H7, a Gram-negative, has all of the following structures EXCEPT

• lipid A.
• teichoic acid.
• LPS.
• porins.
• O-polysaccharides.

Answer 18

• teichoic acid.

Question 19

Which of the following places the steps of the Gram stain in the correct order?

1-Alcohol

2-Crystal violet

3-Safranin

4-Iodine

• 1-2-3-4
• 1-3-2-4
• 2-4-1-3
• 4-3-2-1
• 2-1-4-3

Answer 19

• 2-4-1-3

Question 20

Which is NOT a function of bacterial cell wall?

• to support for fragile cell membrane.
• to transport highly hydrophilic molecules.
• to serve as a point of anchorage for flagella.
• to maintain the bacterial cell shape.
• to contribute to pathogenesis of some pathogenic bacteria.

Answer 20

• to transport highly hydrophilic molecules.

Question 21

Gram-variables show different gram staining result as the culture ages, probably because

• the peptidoglycan layer gets thicker.
• they increase the volume of periplasm.
• the teichoic acid layer gets thicker.
• the peptidoglycan layer gets thinner.
• the LPS layer gets thinner.

Answer 21

• the peptidoglycan layer gets thinner.

Question 22

Which part of LPS is responsible for septic shock?

• O polysaccharide
• lipid A
• core polysaccharide
• H antigen
• O antigen

Answer 22

• lipid A

Question 23

High concentration of _____ in the wall of Mycobacterium tuberculosis is the main reason why the staining of the bacterium requires a special treatment.

• arabinose
• peptidoglycan
• lipoteichoic acid
• carbolfuchsin
• mycolic acid

Answer 23

• mycolic acid

Question 24

Penicillin kills bacterial cells by

• enhancing lysozyme activity.
• producing less peptidoglycan precursor molecules.
• inhibiting transpeptidase activity.
• inhibiting transglycosylase activity.
• inhibiting lysozyme activity.

Answer 24

• inhibiting transpeptidase activity.

Question 25

If you treat E. coli (a Gram-negative) with lysozyme inside an isotonic solution for a long time, - E. coli membrane shrinks. - E. coli cell is lysed. - E. coli L-form is produced. - E. coli protoplast is produced. - E. coli spheroplast is produced

Answer 25

- E. coli spheroplast is produced

Question 26

The proton motive force is DIRECTLY responsible for the following functions in the bacterial cell EXCEPT, - primary active transport - symport - ATP production - antiport - flagella motility

Answer 26

- primary active transport

Question 27

The flexibility of bacterial membrane is regulated by - peptidoglycan. - polyenes. - sterols. - hopanoids. - cholesterols.

Answer 27

- hopanoids.

Question 28

Some aquatic microaerophiles use _____ to orient their swimming downward along the magnetic grids of Earth until they reach a suitable attachment site. - carboxysomes - magnetosomes - gas vacuoles - sulfur granules - lipid inclusions

Answer 28

- magnetosomes

Question 29

Endospore formers include species of - gram-negative bacilli. - Clostridium. - Escherichia. - cyanobacteria. - All of the above

Answer 29

- Clostridium.

Question 30

Which is NOT a reason for endospores to have resistance to boiling, UV, chemicals like H2O2, and desiccation? - formation of only one endospore inside the mother cell. - Ca2+-dipicolinate. - Small-acid soluble proteins. - lack of water. - All of the above are reasons for the endospore's resistance.

Answer 30

- formation of only one endospore inside the mother cell.

Question 31

Louis Pasteur disproved spontaneous generation with the concept of _____ which states that living cells can arise only from preexisting living cells. He demonstrated that microorganisms are present in the air and can contaminate sterile solutions by using a special flask named _____.

Answer 31

biogenesis/swan-neck flask

Question 32

Pasteur’s solution to the spoilage problem of wine was ______ where beer, milk, and wine are heated just enough to kill most of the bacteria that caused the spoilage.

Answer 32

pasteurization

Question 33

Koch proved that Bacillus anthracis caused anthrax in cattle by establishing ____, a sequence of experimental steps that directly relate a specific microbe to a specific disease.

Answer 33

Koch's postulates

Question 34

The beta-1,4-linkage in peptidoglycan can be degraded by an enzyme named ____ found in tears.

Answer 34

lysozyme

Question 35

Due to high concentration of a hydrophobic waxy lipid in the cell wall, Mycobacterium tuberculosis must be stained with heating. This staining method is called ______.

Answer 35

acid-fast staining

Question 36

Streptococcus pneumoniae, a causative bacterium for pneumonia, has a _____ which surrounds the bacterium in an organized manner and firmly attaches to the cell wall. Without this structure, S. pneumoniae becomes avirulent.

Answer 36

capsule

Question 37

What are the three basic shapes of bacteria? Also, briefly describe at least two variations of each shape.

Answer 37

1. coccus (round); diplococcus, streptococcus, staphylococcus... 2. bacillus (rod): diplobacillus, streptobacillus... 3. spiral: spirillum, spirochete...

Question 38

Treponema pallidum, a spirochete casing syphilis, uses a special appendage to propel itself. a) What is the name of this structure? b) Briefly explain why this structure is more beneficial to the bacterium than flagella.

Answer 38

a) axial filaments or endoflagella | b) better in moving through thick viscous tissue.

Question 39

Why is the potassium uniport an example of secondary active transport system even though it does not involve the actual co-transport of a proton?

Answer 39

it uses only part of PMF, the electrochemical gradient.