Microbiology Exam II

Viruses

simply want to replicate

Viruses are not considered living because

they have no ribosomes

Capsomeres

are the protein units that make up the capsid

Budding, when it refers to viruses, has to do with

replication of enveloped viruses

Clostridium botulinum produces a toxin because

it contains a prophage

The best way to prevent a viral infection is

get vaccinated if a vaccine is available

If you have a pet potato and you don’t want it to get sick, keep it away from

viroids
If you see a deer staggering around in the woods, you might want to avoid it
because it may have

If you see a deer staggering around in the woods, you might want to avoid it
because it may have

chronic wasting disease

Prions

are altered brain proteins

The breakdown of lactose into glucose galactose

is a spontaneous reaction

ATP is the energy currency of living cells because

the amount of energy that it takes for the cell to make ATP is reasonable

Enzymes

are always proteins, catalyze ONLY spontaneous reactions, and catalyze reactions that might take a year to occur on their own

Enzyme activity

slows down at temperatures below and greater than optimal temperature

Wild type E. Coli does not require _______ as a nutrient.

essential metabolites

With respect to temperature, organisms that grow optimally at human body
temperature of 37oC are referred to as

mesophiles

Humans produce _______ and its corresponding dismutase.

superoxide

In which phase of growth are bacterial growing the most rapidly?

log phase

A microorganism that is found in an alkaline (pH 10.0) environment

will probably die in a neutral pH medium

Which of these methods might count dead cells found in an original bacterial
culture?

direct microscopic count

Proteins are not considered nutrients for a cell because

they are simply too big to get into the cell

Nitrogen fixation

occurs in some microorganisms

E. coli is a chemo_____ while most of the archea are chemo_______.

heterotroph, autotrophs

The type of ATP generation where a phosphate is donated directly from an
organic molecule is

substrate-level phosphorylation

One purpose of fermentation is

to reduce pyruvic acid

The oxidation of glucose ultimately to carbon dioxide is an example o

catabolism

Oxidative phosphorylation is directly associated with

the electron transport chain

In biological oxidations, what is typically removed from a molecule?

hydrogen atoms

Streptococcus typically carries out fermentation only because

it is missing an enzyme in the Kreb’s cycle

NAD+ is a

coenzyme

Most of the CO2 released by an organism performing respiration is released in

the Kreb’s cycle

A major difference between fermentation and respiration is

fermentation uses an organic final electron acceptor

We need molecular oxygen

to serve as a final electron acceptor only

ATP synthase is involved in

oxidative phosphorylation

The Proton Motive Force

is the force of electrons going through the Electron Transport Chain, uses ATP to pump protons out of the cell, and transports certain amino acids into the cell

The Core Pathways

are glycolysis and the Kreb’s cycle

The poison, cyanide, interferes directly with

the electron transport chain

E.coli, in the presence of molecular oxygen and nitrate, predominantly carries out

aerobic respiration

Which molecule in repiration contains the most energy

glucose (or the original carbon source)

Fatty acids, which are break-down products from fats, enter metabolism

in one of the Core Pathways

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

most of its carbons are oxidized in the Kreb’s cycle

Viral capsids:

protects nucleic acid, contains receptor binding sites, makes up the shape of the virus, and is composed of capsomeres

Viral envelopes

are dervied from the cell membrane of the host cell

When an animal DNA virus infects a cell

DNA replication takes place inside a host cell

One thing that a bacteriophage normally does that an animal virus may or may not do

lyse the host cell

Lysogeny

sometimes results in the host cell producing toxins

If you were setting up an experiment on viruses, which of the following would be important to maintain the viruses used in the experiment?

host cells

An oncogenic virus

is a cancer-causing animal virus

Another name for mad cow disease is

bovine spongiform encephalopathy (BSE)

The model of how a prion works is that

the infectious protein causes normal brain proteins to become altered

Which of the following statements about viruses is FALSE?

viruses use their own catabolic enzymes

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 on 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

The term aerotolerant anaerobe refers to an organism that

does not use oxygen but tolerates it

Which of the following is an organic growth factor?

vitamin B1

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

superoxide dismutase

Which of the following is an advantage of the direct microscopic count?

requires no incubation time

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

log phase

Which of the following is the best definition of generation time?

the length of time needed for a cell to divide

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

Which of the following is the best 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

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

it is converted into acetyl CoA

A bacterium that only possesses the ability to ferment obtains energy

by glycolysis only

All of the following are required in the reactions of microbial respiration EXCEPT

oxygen

The yeasts are growing well on the maltose medium but are not producing alcohol. What is the most likely explanation?

O2 is in the medium

Which organism is NOT correctly matched to its energy source?

photoautotroph - CO₂

Which of the following uses CO₂ for carbon and H₂ for energy?

chemoautotroph

Which of the following uses glucose for carbon and energy?

chemoheterotroph

Cyanobacteria are a type of

photoautotroph