mcb3023 exam 4

When the diet of a ruminant is drastically changed from grass to a starch rich diet, the ruminant may become very ill or die because

of the production of large amounts of acid, resulting in acidosis

Lichens contain

at least one fungal heterotrophic partner and at least one phototrophic partner

The bacterial group that is responsible for root nodule formation in legumes is

Rhizobia

Humans have a

colonic fermentation

Leghemoglobin produced by plants is important for

oxygen supply

Which of these contains zooxanthellae as photosynthetic symbionts?

corals

How do termites obtain nitrogen in their diet?

From nitrogen fixing bacteria in their gut.

These genes are important for root nodule formation

nod

The majority of Archaea found in the human intestinal tract are

methanogens

What is an endophyte?

a symbiont that lives inside plant cells

What is the human microbiome composed of?

all microbes that live on or within the human body

What are Zooxanthellae?

photosynthetic symbionts of corals

Most primary endosymbionts of insects have all these in common, EXCEPT

nitrogen fixation genes

An example of a rumen fermenter is the

sheep

Many of the rumen bacteria specialize in the breakdown of these macromolecules

cellulose polymers

Which genes are encoding for subunits of nitrogenase, the main enzyme for nitrogen fixation?

nif genes

What is the e- donor for bacterial symbionts of tubeworms at hydrothermal vents?

H2S

Which of these is characteristic of the enzyme nitrogenase?

it is irreversibly inactivated by oxygen

Camels have a

rumen fermentation

Herbivores mostly require microorganisms to help them with the digestion of this compound

cellulose

Which of these is true of a mutualistic relationship?

both organisms benefit

How does vertical transmission of a pathogen occur?

From mother to offspring

The Ebola virus is transmitted by a ____ mechanism

zoonotic

This is an example of a virus known to undergo evolutionary change by reassortment of genetic elements:

influenza virus

Antibodies are:

produced by B cells

Some T cells (T lymphocytes):

induce necrosis of cells

In the CRISPR-Cas System, which component is responsible for phage destruction?

cRNA subunits

Which is an example of innate immunity?

The removal of a bacterial cell in the lungs by a resident macrophage

Which cells are destroyed by hemolysins?

red blood cells

LPS in Gram-negative contain

an O-antigen

Which one of the following statements is NOT one of Koch's postulates?

identify and characterize endotoxins from the isolated microbe

Which is studied in the field of epidemiology?

the spread patterns of all diseases

Name the type of viral infection in which the viral genome is present in infected cells but the virus only replicates sporadically

latent

Which of these could be accomplished with an ELISA?

detection of specific antibodies in serum

Pathogenicity islands are blocks of genes on the bacterial chromosomes that most likely arose from this process

horizontal gene transfer

The emergence of HIV/AIDS disease was most likely a result of:

a rare zoonotic transfer of a retrovirus strain to humans

Pathogenic E. coli strain O157:H7 evolved from a non=pathogenic strain as a result of this genetic change

the acquisition of virulence genes via horizontal gene transfer

The term describing a clustering of virulence genes on the chromosome of a pathogenic microbe is:

pathogenicity island

Which of these results in immunological memory?

the adaptive immune response

Which one of the following is NOT a nonspecific natural defense barrier against microbial invasion?

antibodies produced from B lymphocytes

What is the primary effect of microbial lipopolysaccharides (LPS) on the host?

Triggers an intense inflammatory response

Botulinum toxin belongs to a group of toxins called A-B toxins. What does the term "A-B" refer to?

Their enzymatically active subunit and their cell-binding subunit.

The Tir/Intimin system of pathogenic E. coli is used for

attachment to host cells

Which of these is NOT a mechanism of horizontal gene transfer?

inherited DNA from mother cell to daughter cell

The term for properties of pathogens that aid in causing disease is:

virulence factors

Bacteria can 'steal' iron from host cells through their production of:

siderophores

Evolution of viruses by reassortment causes dramatic changes to the virus. This is referred to as _____________ .

antigenic shift

What are the two main functions of B cells?

Activation of helper T cells and antibody production.

What is the prevalence rate of a disease?

The number of cases of the disease within a specified number of the population.

Name the type of viral infection in which the viral genome is present in infected cells but the virus only replicates sporadically.

latent

Why do RNA viruses have a high mutation rate?

Their RNA-dependent RNA polymerases lack a proofreading function.

All of the following are components that may be used by a pathogen for attachment to a host cell EXCEPT:

cellulase?

Which of these would lead to a recombination of genetic elements in viruses?

Co-infection of a cell by two different strains of the virus.

Exogenous antigen is usually taken up by antigen-presenting cells through phagocytosis, processed, and presented to T cells on their surface by these:

MHC molecules

The process of point mutational change in the surface proteins of viruses is an example of:

antigenic drift

All of the following are clinical signs of inflammation at the site of injury EXCEPT:

constriction of blood vessels.

The term for the number of NEW cases of a disease within a population during a specific time period is:

incidence rate

Rhinovirus is a cause of the common cold. What type of infection does it usually cause?

acute

Cytolysins:

form pores or destroy plasma membranes

These are cells of the innate immune system:

macrophages

In the CRISPR-Cas system, which component is responsible for the bacterial equivalent of "immune memory"?

CRISPR Locus

What does a high case-to-infection ratio (CI) indicate?

That most people infected by the pathogen will develop the disease.

In order to cause a fast spreading disease, successful infectious pathogens must be able to do ALL of the following EXCEPT:

kill the host.

Pathogens that have the ability to change their surface antigens are better able to do which of the following?

evade host defenses

An attachment structure which aids in overcoming the charge repulsion between host/microbe cells is:

Fimbriae

Which of these is true of an endemic disease?

It is constantly present in a given population.

For most pathogenic bacteria, what is the first step it takes to facilitate entry into its host?

attachment

Penicillin was discovered by:

Alexander Fleming

The smallpox vaccination used by Jenner is best described as a(an)

attenuated vaccine

If ninety percent of a population is immune to a particular disease they protect the susceptible ten percent by a concept known as:

herd immunity.

All of the following are approaches used to help reduce the incidence of antimicrobial drug resistance EXCEPT

the use of very high concentrations of the drug

The best way to prevent a cholera epidemic is

proper drinking water treatment

Mutational resistance to an antimicrobial drug usually occurs ...

spontaneously in the absence of the drug.

Which one of the following is NOT a common mechanism of antimicrobial drug resistance?

incorporation of the drug into cell material

Subunit vaccines are generally considered safer than attenuated vaccines because

attenuated vaccines may permit viral growth and possible mutation.

Attenuated vaccines are generally more effective than subunit vaccines because:

attenuated vaccines may permit viral growth with enhanced disease mimicry

The targets for common groups of antibiotics for bacteria are all EXCEPT

LPS biosynthesis