Micro Chapter 7

Question 1

Sexual reproduction is a characteristic of which of the following domain?
	A)	Archaea only
	B)	Bacteria only
	C)	Eukarya only
	D)	All of the above

Answer 1

C

Question 2

Which of the following reproductive methods is common to the bacteria?
	A)	Binary fission
	B)	Budding
	C)	Formation of uninucleoid spores
	D)	All of the above

Answer 2

D

Question 3

Replication of the bacterial chromosome is
	A)	Unidirectional
	B)	Bidirectional
	C)	Random
	D)	None of the above

Answer 3

B

Question 4

In bacterial reproduction, chromosomal partitioning of daughter cells is best described by
A) Pushing of chromosomes to opposite sides by RNA polymerase
B) Condensation of daughter chromosomes pulls the DNA to opposite sides
C) A cytoskeletal protein MreB moves the DNA to opposite poles
D) All of the above

Answer 4

D

Question 5

The most critical step in cytokinesis is
A) Assembly of the Z ring
B) Assembly of the cell wall-synthesizing machinery
C) Constriction of the cell and septum formation
D) Selection of the site where the septum will be formed

Answer 5

A

Question 6

Peptidoglycan synthesis starts in the
	A)	Cytoplasm
	B)	Cell membrane
	C)	Cell wall
	D)	Periplasmic space

Answer 6

A

Question 7

Autolysins are involved in
A) Linking strands of peptidoglycan together
B) Linking peptidoglycan to the plasma membrane
C) Degrading the glycosidic bonds between peptidoglycan molecules
D) None of the above

Answer 7

C

Question 8

The new cell wall in reproducing rods forms
A) Only at the septum
B) Homogenously around the forming cell
C) Bends along the sides of the cell but not at the poles
D) None of the above

Answer 8

C

Question 9

Organisms incubated in a closed culture vessel with a set volume of media is known as a(n)
	A)	Open culture
	B)	Batch culture
	C)	Closed culture
	D)	Exponential culture

Answer 9

B

Question 10

Cells begin synthesizing new components during the \_\_\_\_\_\_\_\_\_\_ phase.
	A)	Lag
	B)	Exponential
	C)	Stationary
	D)	Death

Answer 10

A

Question 11

During the \_\_\_\_\_\_\_\_\_\_\_\_ phase, microorganisms grow and divide at their maximum rate.
	A)	Log
	B)	Exponential
	C)	Lag
	D)	Death

Answer 11

B

Question 12

Balanced growth in which all cellular constituents are manufactured at a constant rate, occurs during the \_\_\_\_\_\_\_\_\_\_\_ phase.
	A)	Lag
	B)	Exponential
	C)	Stationary
	D)	Death

Answer 12

B

Question 13

A balance between cell division and cell death occurs in the \_\_\_\_\_\_\_\_\_\_\_\_\_ phase.
	A)	Lag
	B)	Exponential
	C)	Stationary
	D)	Death

Answer 13

C

Question 14

Why do microbial populations enter the stationary phase?
	A)	Nutrient limitation
	B)	Accumulation of toxic waste products
	C)	Limited oxygen availability
	D)	All of the above

Answer 14

D

Question 15

Proteins that make the cell more resistant to damage by starvation are called
	A)	Starvation proteins
	B)	Heat-shock proteins
	C)	Survival proteins
	D)	Endospores

Answer 15

A

Question 16

The number of viable cells decreases exponentially in the \_\_\_\_\_\_\_\_\_\_\_\_ phase.
	A)	Lag
	B)	Exponential
	C)	Stationary
	D)	Death

Answer 16

D

Question 17

In death phase,
A) The number of living cells declines exponentially
B) Cells become viable but non-culturable (VBNC)
C) Undergo programmed cell death
D) All of the above

Answer 17

D

Question 18

The number of generations per unit time is defined as
	A)	The mean growth rate
	B)	The mean generation time
	C)	The mean doubling time
	D)	Exponential growth

Answer 18

A

Question 19

Which of the following variables is important to calculating the microbial mean growth rate?
	A)	Initial population number
	B)	The population number at time, t
	C)	The number of generations in time t
	D)	All of the above

Answer 19

D

Question 20

Which of the following methods would be best for counting the number of protists in a water sample?
A) The Petroff-Hausser counting chamber
B) The Coulter counter
C) Membrane filtration
D) Determination of microbial dry weight

Answer 20

B

Question 21

The best method for counting living bacterial and archaeal cells is
	A)	The Petroff-Hausser counting chamber
	B)	The hemocytometer
	C)	The Coulter counter
	D)	Membrane filtration

Answer 21

A

Question 22

Which of the following is not an example of a viable counting method?
	A)	Streak plate
	B)	Pour plate
	C)	Hemocytometer
	D)	Membrane filtration

Answer 22

C

Question 23

The most rapid and accurate method for measuring cell mass is
A) Measuring microbial dry weight
B) Spectrophotometry
C) Measuring the concentration of another cellular substance
D) None of the above

Answer 23

B

Question 24

A more turbid broth culture of bacterial cells will result in
A) A high absorbance reading with the spectrophotometer
B) A low absorbance reading with the spectrophotometer
C) No reading on the spectrophotometer
D) None of the above

Answer 24

A

Question 25

Bacterial cells growing in a chemostat will grow more with which of the following changes?
A) Decreasing the dilution rate
B) Increasing the dilution rate
C) Increasing the volume of the container
D) Decreasing the flow rate

Answer 25

B

Question 26

Turbidostats work by
	A)	Maintaining constant nutrient concentrations
	B)	Increasing the flow rate
	C)	Maintaining a desired cell density
	D)	All of the above

Answer 26

C

Question 27

If a bacterial cell is placed into a hypertonic solution, then
A) Water will move into the cell and the cell will shrink
B) Water will move into the cell and the cell will expand
C) Water will move out of the cell and the cell will shrink
D) Water will move out of the cell and cell will lyse

Answer 27

C

Question 28

Microbial cells respond to osmotic stresses by
A) Opening and closing mechanosensitive (MS) channels
B) Storing compatible solutions inside the cell
C) Using a contractile vacuole to expel excess water
D) All of the above

Answer 28

D

Question 29

Organisms that do not require oxygen for growth but grow better in its presence are called
	A)	Obligate aerobes
	B)	Facultative anaerobe
	C)	Aerotolerant anaerobe
	D)	Obligate anaerobe

Answer 29

B

Question 30

Organisms that grow optimally at temperatures at 55�C or higher are called
	A)	Psychrophiles
	B)	Psychrotrophs
	C)	Mesophiles
	D)	Thermophiles

Answer 30

D

Question 31

Organisms that grow optimally within a pH range of 0 and 5.5 are called
	A)	Acidophiles
	B)	Neutrophiles
	C)	Alkalophiles
	D)	Hyperalkalophiles

Answer 31

A

Question 32

Acidophiles survive in low pH environments by
A) Increasing their cell size
B) Pumping protons outside the cell if they get in
C) Making the plasma membrane permeable to water
D) None of the above

Answer 32

B

Question 33

Microbes are vulnerable to high temperatures because
A) High temperatures disrupt the cell wall
B) High temperatures decrease the amount of oxygen available to the cell
C) High temperatures inactivate enzymes responsible for metabolism
D) None of the above

Answer 33

C

Question 34

Thermophiles have which of the following adaptations for survival at high temperatures?
A) They have heat-stable enzymes and proteins
B) They have lipids that span the membrane to form a rigid monolayer
C) They have more saturated membrane lipids
D) All of the above

Answer 34

D

Question 35

Photosynthetic protists are most likely
	A)	Obligate aerobes
	B)	Facultative anaerobes
	C)	Obligate anaerobes
	D)	Aerotolerant anaerobes

Answer 35

A

Question 36

Which of the following enzymes protect microbes against toxic oxygen (O2) products?
	A)	Catalase
	B)	Permease
	C)	Hydrolase
	D)	All of the above

Answer 36

A

Question 37

Microbes can be grown in anaerobic conditions by
A) Removing oxygen chemically with a palladium catalyst
B) Remove air from the growth chamber with a vacuum
C) Add carbon dioxide (CO2) to the growth chamber to drive out oxygen
D) All of the above

Answer 37

D

Question 38

Organisms that grow in the deepest trench of the Pacific Ocean are classified as
	A)	Barotolerant
	B)	Piezophilic
	C)	Barophobic
	D)	None of the above

Answer 38

B

Question 39

Which of the following forms of radiation is most harmful to microbes?
	A)	Visible light
	B)	Infrared rays
	C)	Ionizing radiation
	D)	Radio waves

Answer 39

C

Question 40

Ultraviolet (UV) radiation can kill microorganisms because it
A) Damages the cell wall by creating pores
B) Damages DNA by forming thymine dimers
C) Damages the plasma membrane by disrupting hydrophobic interactions
D) All of the above

Answer 40

B

Question 41

Visible light is damaging to microbial cells because
A) It damages the cell wall
B) It damages DNA
C) It generates singlet oxygen and oxidizes cells
D) All of the above

Answer 41

C

Question 42

The purpose of the extracellular polymeric substance (EPS) matrix created by biofilms is to
A) Stick more stably to a surface
B) Enhance diffusion of oxygen and nutrients
C) Preconditioning a surface for other cells
D) Communicating with other cells

Answer 42

A

Question 43

Which of the following is not true of bacterial biofilms?
A) Some microbes can use the waste products created by other microbes as metabolites
B) Microbes can uptake DNA from the EPS
C) Microbes are capable of communicating via chemical signals
D) Biofilms are extremely vulnerable to antibiotics

Answer 43

D

Question 44

A density-dependent chemical communication between microbes is known as
	A)	Autoinducing
	B)	Quorum sensing
	C)	Group translocation
	D)	Phosphorelay systems

Answer 44

B

Question 45

Vibrio fischeri populations inside warm-water squids bioluminesce when
A) When N-acylhomoserine lactone (AHL) reaches threshold levels
B) When autoinducer-2 (AI-2) reach critical levels
C) When oligopeptide chemical signals decrease
D) All of the above

Answer 45

A