Biology launchpad chapter 14 questions USM

Which of the following puts a healthy person at greater risk for a MRSA infection?

- a medical procedure that weakens the immune system - undergoing a procedure that causes a break in the skin - being a child whose immune system is still maturing - being elderly ( ANSWER ALL OF THE ABOVE)

Which of the following is a high-risk group for MRSA?

- children in day care centers - individuals in prison - men who have sex with men - certain ethnic groups ( ANSWER = ALL OF THE ABOVE)

Which of the following would NOT be effective against a drug-resistant strain of staph?

- penicillins - cephalosporins - methicillin (ANSWER = THE FIRST THREE ANSWERS ARE CORRECT)

Treating and preventing infections by antibiotic-resistant bacteria can be accomplished by:

- reducing antibiotics in livestock feed - washing hands frequently - disinfecting common surfaces - researching new vaccines ( ANSWER= ALL OF THE ABOVE)

MRSA and drug resistance staph refer to:

- staph strains that are resistant to penicillins - staph strains that are resistant to cephalosporins - staph strains that are resistant to beta-lactams ( ANSWER: the first three answers are correct)

MRSA sickens some 94,000 people in the United States each year and kills almost

19,000

Experts estimate that about _____ of the U.S. population (nearly 90 million people) is colonized by S. aureus.

30% to 40%

The response of a population to environmental pressure so that advantageous traits become more common in the population over time is called:

ADAPTATION

Methicillin is currently used to treat staph infections T/F ?

FALSE

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

staph bacteria are harmless to most people who carry them: T/F ?

TRUE

An antibiotic-resistant allele confers a fitness cost. What would you predict about the growth of the bacteria with the resistant allele compared to the growth of bacteria without the sensitive allele in the presence or absence of antibiotics?

The sensitive strain will have the highest fitness in the absence of antibiotic, and the resistant strain will have the highest fitness in the presence of antibiotic.

MRSA is caused by:

a drug-resistant form of Staphylococcus Aureus

Chemicals that either kill bacteria or slow their growth by interfering with the function of the essential bacterial cell structures are:

antibiotics

A type of asexual reproduction in which one parent cell divides into two is called:

binary fission

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

by gene exchange and mutation

If you carry staph of any strain but aren't sick, you are:

colonized

A sensitive S. aureus bacterium acquires a new gene that allows it to resist the effects of β-lactam antibiotics. What might the protein encoded by that gene do?

digest β-lactam antibiotics

S. aureus can be transferred from person to person by:

direct contact with contaminated skin the use of soap and towels contaminated surfaces

The evolution of antibiotic resistance is an example of:

directional selection

A type of natural selection in which organisms with phenotypes at both extremes of the phenotypic range are favored by the environment is:

diversifying selection

the relative ability of an organism to survive and produce in a particular environment is known as:

fitness

Where is MRSA most likely to be a problem?

in the bloodstream

bacteria can become resistant to drugs by :

mutations and acquiring "resistance genes."

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

natural selection

Which of the following hypothetical antibiotics would treat bacterial infections by interfering with bacterial reproduction?

one that decreases cell membrane synthesis

Fitness is determined by the interaction between _____ and the environment.

phenotype

Staphylococcus Aureus is a spherical bacterium that can cause :

pimples, boils and wound infections

A group of organisms of the same species living together in the same geographic area is called an:

population

Which of the following is a harmful bacterium?

salmonella

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?

stabilizing selection

An organism's fitness depends on its environment.

true

Even though mutation rates for bacteria and humans are identical, bacteria are able to adapt more quickly to their environment than are humans. T/F?

true

MRSA is composed of a number of unique strains of staph bacteria T/F ?

true

Which of the following is the drug of choice when a serious MRSA infection is present?

vancomyosin

Antibiotic-resistant bacteria have _____ fitness in the presence of antibiotics.

very high