Bio HW Ch. 14

C. not necessarily; fitness depends on the ability of an organism to survive and reproduce, and it may not do this as well in a different environment

If we take the most fit bacterium from one environment--one in which the antibiotic amoxicillin is abundant, for example--and place it in an environment in which a different antibiotic is abundant, will it retain its high degree of fitness?

C. Stabilizing selection

In humans, very large birth weight babies and very tiny babies do not survive as well as midrange babies. What kind of selection is acting on human birth weight?

A. Directional selection

The evolution of antibiotic resistance is an example of:

A. Staphylococcus aureus bacteria that are resistant to many antibiotics

The term "MRSA" as it is used today refers to:

C. Gene exchange and mutation

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

D. The presence or absence of antibiotics in the environment

What is the environmental pressure in the case of antibiotic resistance?

C. In the bloodstream

Where is MRSA most likely to be a problem?

Beta-lactam antibiotics work by interfering with the bacteria's ability to synthesize cell walls. Our eukaryotic cells are not affected because there is no cell wall in animal cells

Why do the beta-lactam antibiotics affect sensitive bacterial cells but not eukaryotic cells?

a. It is troublesome to hear because antibiotics will not kill the virus and the increase in antibiotics in the environment will increase the chance that bacteria in the environments will become resistant b. No C. The risk to the friend is the bacteria becoming resistant, which will continue to replicate ad leave him with a resistant population of bacteria. This could be transferred to others.

Your friend has had a virus caused cold for 3 days and it still so stuffy and hoarse hat he is hard to understand. He seems to be telling you that his doctor called in a prescription for an antibiotic for him to pickup at his pharmacy. You hope you misunderstood him, but you realize you him perfectly. a. Why are you dismayed to hear his story? b. Will the antibiotic help your friends cold? c. What are the risks to your friend if he takes the antibiotic? What are the risks to you, as his friend?