Microbio Exam 2 (assignment q's)

Which of the following statements about viruses is false?

viruses use their own catabolic enzymes

Why do most scientists agree that viruses are nonliving entities?

they are not composed of cells

Which of the following is NOT used as a criterion to classify viruses?

biochemical tests

Which of the following statements about viral spikes is false?

they are found only in nonenveloped viruses

The definition of lysogeny is

phage DNA is incorporated into host cell DNA

An envelope is acquired during which of the following steps?

release

a viroid is an

infectious piece of RNA without a capsid

An infectious protein is a

prion

Which of the following is an organic growth factor?

vitamin B1

Which enzyme catalyzes the reaction: O₂- + O₂- + 2H⁺ → H₂O₂ + O₂?

superoxide dismutase

What is an advantage of the standard plate count method?

determines the number of viable cells

What is an advantage of the direct microscopic count?

requires no incubation time

How do most bacteria reproduce?

binary fission

The figure shows a typical bacterial growth curve with the y-axis indicating the log of the number of bacteria and the x-axis indicating time in culture. In the figure, which sections of the graph illustrate a logarithmic change in cell numbers?

b and d

During which growth phase will gram-positive bacteria be most susceptible to penicillin?

log phase

Definition of generation time

the length of time needed for a cell to divide

Three cells with generation times of 60 minutes are inoculated into a culture medium. Assuming no lag phase takes place, how many cells are there after 5 hours?

96

Which of the following compounds is not an enzyme?

coenzyme A

Which of the graphs in the figure best illustrates the activity of an enzyme that is saturated with substrate?

c

ATP is a common intermediate between

catabolic and anabolic pathways

Anaerobic organisms are capable of generating ATP via

respiration

ATP can be generated by the

flow of protons across protein channels

In the conversion of isocitric acid to a-ketoglutaric acid, what compound is being reduced?

NAD+ is converted to NADH + H⁺

How is ATP generated in disphosphoglyceric acid —> 3-phosphoglyceric acid?

substrate-level phosphorylation

Definition of oxidative phosphorylation

A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP

Anaerobic respiration does

require cytochromes, yields lower amounts of ATP when compared to aerobic respiration, utilizes complete Krebs cycle, generates ATP

Anaerobic respiration doesn’t

involve the reduction of an organic final electron acceptor

What is the fate of pyruvic acid in an organism that uses aerobic respiration?

It is converted into acetyl CoA.

What is produced during the Krebs cycle?

NADH, CO₂ , FADH₂, ATP

A bacterium that only possesses the ability to ferment obtains energy

by glycolysis only

What is required in the reactions of microbial respiration?

a source of electrons, final electron acceptor, electron transport system, cytochromes

A bacterium such as Pseudomonas uses nitrate as a final electron acceptor in an electron transport system. All the below statements are true EXCEPT

they require light

Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol. The yeasts are growing well on the maltose medium but are not producing alcohol. What is the most likely explanation?

oxygen is in the medium

In aerobic respiration, where is water found?

d

Where is ATP produced?

e

The structure labeled 1 is

the plasma membrane

The path labeled 2 is the flow of

protons

What is the most acidic place in the figure?

a

Chemoautotroph energy source

Fe²⁺

Photoautotroph energy source

light

photoheterotroph energy source

light

Chemoautotroph energy source

NH₃

Chemoheterotroph energy source

glucose

What organism uses CO₂ for carbon and H₂ for energy?

chemoautotroph

What uses glucose for carbon and energy?

chemoheterotroph

Cyanobacteria are a type of

photoautotroph

Viruses are

obligate intracellular parasites, non-living, only purpose is to replicate

Why aren’t viruses living?

not cells, can only replicate inside of a host cell, no ATP generating system, no ribosomes, contain only one nucleic acid, no metabolism

What does every virus have?

nucleic acid and capsid

What is the heart of the virus?

nucleic acids

Herpes has

double stranded DNA

B19 - fifth disease has

single stranded DNA

Rotavirus has

double stranded RNA

Rhinovirus, flu virus, and SARS Cov-2 has

single stranded RNA

How do you classify viruses?

shape, size, nucleic acid type, envelope or not, virus specificity

Replication of a DNA-containing animal virus steps

attachment, entry & uncoating, viral DNA transcribed, biosynthesis, late translation, maturation, release