Biology Chapter 13

Which group is NOT at a high risk for acquiring MRSA?

Individuals at a grocery store

In the presence of antibiotics:

Synthesis of the cell wall is disrupted.

An organism's fitness depends on its environment.

True

What are the two major mechanisms by which bacterial populations generate genetic diversity?

by gene transfer and mutation

Which of these is NOT a reason that hospitals remain hot spots for staph infections?

doctors and nurses neglecting patients

The change in allele frequencies in a population over time is called:

evolution.

A non-staph bacterium that is resistant to penicillin and a staph bacterium are found in the same host. After the bacteria grow and replicate, it is found that the staph bacteria is now penicillin resistant. This is likely due to between the two bacteria.

gene transfer

Which hypothetical antibiotic would treat bacterial infections by interfering with bacterial reproduction?

one that decreases cell membrane synthesis

The graph shows _________ selection. If it showed a change from medium birth weight babies being the majority to only low birth weight babies being the majority, this would be__________ selection.

stabilizing; directional

A physician had prescribed a beta-lactam antibiotic for a woman's sister. Her sister took biology in high school and is refusing to take the antibiotic because she says that it will affect osmosis in her cells. Which reason can the woman use to help her sister understand how the antibiotic will work?

Beta-lactam affects bacterial cell walls, and it can't affect human cells because they do not have cell walls.

A highly resistant antibiotic strain of S. aureus would reproduce:

Equally well in the presence or absence of antibiotic.

A patient goes to the hospital with large pimples on the chest. The test for S. aureus returns positive on the skin, but negative in the blood. The patient is therefore colonized with S. aureus because it was only found on the skin.

False

Methicillin is currently used to treat staph infections.

False

A high school football player fainted during a game after complaining of headache, fever, and flu-like symptoms. Two weeks before the game, he noticed a rash on his lower back. How should the football player respond to his symptoms?

Immediately seek medical attention to test for severe strains of staph.

Where is MRSA most likely to be a problem?

In the bloodstream

Why do beta-lactam antibiotics affect bacterial cells but not human cells?

They target parts of the bacterial cell wall that are not present in eukaryotes because they do not possess cell walls.

The differences in strains of Staphylococcus are contained in its DNA.

True

Differential survival and reproduction of individuals in response to environmental pressure that leads to changes in allele frequencies in a population over time is called:

natural selection.