microbiology chapter 28 homework

Penicillin and other β-lactam antibiotics inhibit cell-wall synthesis. What makes them effective at killing bacterial cells?

Bacteria are generally hypertonic relative to their environment, so they burst when their cell wall is weakened by the action of these antibiotics.

Antifungal medications are often used topically. Why is this the case?

Like human cells, fungal cells are eukaryotic. To develop systemic fungal medications requires finding specific characteristics of fungal cells that can be targeted, such as the ergosterol in fungal cell membranes.

Which antibiotic is overcome by beta-lactamases?

Penicillin

How might efflux pumps increase antibiotic resistance in bacteria?

Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.

Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what?

PABA

Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug?

Penicillin disrupts the cell wall, which is located outside of the cell membrane.

Membrane transport proteins are required for which mode(s) of antibiotic resistance?

Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.

Which of the following immunogens is most effective as a vaccine?

Live virus

 When treating a fungal infection, the best target for selective toxicity would be __________.  

 ergosterol synthesis  

Which of the following materials can be used to create a vaccine?

Attenuated bacteria, inactivated viruses, or recombinant proteins

Which of the following is NOT an autoimmune disease?

anaphylaxis

What does a vaccine contain?

Weakened or killed pathogen or parts of a pathogen

When a person has previously been vaccinated against a viral pathogen, which cells are activated if that same pathogen re-enters the host's cells months or years later?

Memory cytotoxic T cells

What is the primary benefit of vaccination?

An immune response will occur quicker upon future exposure to the pathogen.

What is meant by selective toxicity?

Chemotherapeutic agents should act against the pathogen and not the host.

Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?

Humans and other animal hosts lack peptidoglycan cell walls.

Why is polymyxin only used on the skin?

It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead.

Quinolones and fluoroquinolones act against what bacterial target?

DNA gyrase

Why is it difficult to find good chemotherapeutic agents against viruses?

Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.

 A protein that can stimulate production of an abnormally large number of T cells and cause host damage is termed __________.

a superantigen  

In checkpoint inhibition therapy, which of the following is a protein targeted by therapeutic monoclonal antibodies?

PD-1

Which of the following antibiotic classes prevents supercoiling of bacterial DNA?

Quinolones

Antibiotic resistance is a major concern as microbes can rapidly develop resistance when antibiotics are not used appropriately. Which of the following examples best describes how this occurs?

In any population of microbes, some individuals may have resistance genes. When exposed to an antibiotic, there is selection for the microbes that have these genes.

Type I hypersensitivity is caused by the release of vasoactive products from mast cells coated with

IgE.

   It is difficult to attain good selective toxicity with antiviral drugs because of the fact that __________.    

 viruses require host cells to replicate themselves      

What is the name of the structures formed by recombinant proteins expressed in plants that have been exploited for use in vaccine development?

Virus-like particles (VLPs)

Some antibiotics inhibit protein synthesis by disruption of translation through interactions with the

ribosome.

In Hashimotos's disease, auto-antibodies are made against ________, a product of the thyroid gland.

thyroglobulin