microbiology exam 4 (final)

What is the functional unit of genetic information?

Gene.

Why is supercoiling important for DNA structure?

It condenses the DNA so that it can fit inside the cell.

How are plasmids different from chromosomes?

Plasmids contain genes that are NOT essential for cellular growth and replication.

What is the precursor of each new nucleotide in a strand of DNA?

Deoxynucleoside 5'-triphosphate.

What is an example of correct nucleotide pairing?

A and T.

What is pathogenicity?

The ability of the pathogen to inflict damage on the host.

Which of the following is NOT a subunit of lipopolysaccharide (LPS)?

M protein.

What do Staphylococcus aureus and Streptococcus pyogenes strains produce that causes severe symptoms of toxic shock syndrome?

Superantigen toxins.

What type of toxin is diphtheria toxin?

An AB toxin.

What causes decalcification of tooth enamel?

Lactic acid.

Which bacterial genera is NOT implicated in dental caries?

Borrelia.

What does tetanus toxin cause?

Muscles to be unable to relax.

Shiga toxin is produced by which pathogen?

Shigella dysenteriae.

What are exotoxins and endotoxins?

Exotoxins are proteins, but endotoxins are lipopolysaccharide-lipoprotein complexes.

What is an endogenous pyrogen?

A chemical produced by a host's own immune system that causes fever.

What is immunity?

The ability of humans to resist a disease.

What are cells that can engulf foreign particles and kill bacterial pathogens called?

Phagocytes.

When does adaptive immunity occur?

When the innate immune response fails to eliminate pathogens.

What do blood and lymph have in common?

They are both part of the immune system, but blood contains red blood cells.

Where are stem cells produced and developed?

In the bone marrow.

Which cell type has no nucleus?

Erythrocytes.

What are the secondary lymphoid organs?

Lymph nodes, MALT, and the spleen.

What is immune memory?

The rapid increase in adaptive immunity after a second antigen exposure.

What is an example of a pathogen-associated molecular pattern (PAMP)?

Lipopolysaccharide (LPS).

How do T cells recognize antigens?

With their T cell receptors.

What is antibody-mediated immunity effective against?

Extracellular pathogens.

What is tolerance in immunity?

The acquired inability to mount an adaptive immune response against self.

What intrinsic properties are important for immunogens?

Appropriate physical form, molecular size, and molecular complexity.

What is the part of the antigen recognized by the antibody or TCR?

Epitope.

What is a cross-reaction in immunology?

An interaction between an antibody or TCR and a heterologous antigen.

Where are Class I MHC proteins found?

On the surfaces of all nucleated cells.

What protein coreceptor do Th cells express?

CD4.

What do natural killer cells use to kill targets?

Perforin and granzymes.

Which enzyme is NOT secreted by Th1 cells?

Fibrin.

Where are antibodies found?

Milk, mucosal secretions, and serum.

Which of the following is NOT an immunoglobulin?

IgC.

How is antimicrobial drug resistance usually passed?

By horizontal gene transfer.

What do most drug-resistant bacteria contain?

An R plasmid.

What does the tuberculin skin test identify?

A delayed hypersensitive (DTH) Th1-mediated response.

What is a cause of drug-specific resistance in organisms?

Indiscriminate nonmedical use of antimicrobials.

Which test allows for identification of microorganisms in infected tissues?

Fluorescent antibody (FA) test.

What does EMB agar select for?

Gram-negative bacteria.

What is a zoonosis?

A disease that primarily infects animals but can be transmitted to humans.

What is a fomite?

An inanimate object that transmits infectious agents between hosts.

Which is NOT a public health measure to control disease transmission?

Genetic engineering.

Which microbial group is most resistant to desiccation?

Gram-positive bacteria.

What is the causative agent of streptococcal pharyngitis?

Streptococcus pyogenes.

What causes impetigo?

Infection by either Staphylococcus aureus or Streptococcus pyogenes.

What is rheumatic fever?

An autoimmune disease.

Why can a person be reinfected with Neisseria gonorrhoeae?

Due to the diversity of strains and frequency of mutation.

What virus caused the Spanish flu of 1918?

H1N1 influenza virus.

What is TRUE about chlamydial infections?

Chlamydial diseases can lead to acute complications.

What is the CD4 molecule?

A cell-surface protein that allows HIV to infect a cell.

What type of vaccine component is the diphtheria component of DTaP?

A toxoid.

Which is NOT a staphylococcal disease?

Strep throat.

What type of diseases require BSL 4 procedures?

Highly infectious diseases with high mortality for which no treatment or vaccine exists.

What is the most important potential common source of infectious disease?

Water.

How is malaria controlled?

By reducing the population of the mosquito vector.

What are the most serious types of fungal infections?

Systemic mycoses.

What is a common mechanism for fungal diseases?

Hypersensitivity reactions.