Deck 14: Natural Selection and Adaptation Bugs That Resist Drugs

Question 1

If the cell wall of Staphylococcus aureus fails to form properly,water will

A) create a secondary wall around the cell.
B) drain out of the cell rapidly, causing it to dehydrate.
C) drown the bacteria.
D) rush into the cell, causing it to explode.
E) create a bridge of hydrogen bonds to repair the wall.

Answer 1

rush into the cell, causing it to explode.

Question 2

Which of the following people are at the lowest risk of acquiring MRSA?

A) a computer consultant who works from home
B) someone who works as a guard at a local prison
C) a rugby player on a successful team
D) a worker in a local daycare
E) a janitor at a major city hospital

Answer 2

a computer consultant who works from home

Question 3

All of the following are true of MRSA,EXCEPT

A) MRSA used to be confined to hospitals but now is showing up in healthy individuals outside hospitals.
B) some strains may be resistant to multiple antibiotics.
C) anyone who comes in contact with MRSA will become sick.
D) MRSA can secrete toxins.
E) it can be acquired through inhalation.

Answer 3

anyone who comes in contact with MRSA will become sick.

Question 4

Discuss two possible entry routes for a Staphylococcus aureus infection.

Question 5

A student who shares a dorm suite and bathroom with seven other students has contracted a skin infection caused by MRSA.Based on what you know about MRSA and about the student,where would you look first for the source of the bacteria?

A) contaminated equipment at the gym
B) contaminated shared food
C) contaminated used soap and towels
D) a suitemate with an upper respiratory infection who is sneezing and coughing
E) shared hypodermic needles

Question 6

What percentage of people carry ANY form of Staphylococcus aureus on their skin or in their noses?

A) 1%-5%
B) 5%-10%
C) 10%-25%
D) 30%-40%
E) 50%-60%

Question 7

MRSA is resistant to

A) penicillin.
B) ß-lactam antibiotics.
C) cephalosporin.
D) methicillin.
E) All of the above.

Question 8

Antibiotics should only be prescribed for

A) fungal infections.
B) viral infections.
C) bacterial and fungal infections.
D) bacterial infections.
E) a flulike illness.

Question 9

Explain ways in which you could acquire any Staphylococcus aureus infection (not necessarily MRSA)at the gym.

Question 10

ß-lactam antibiotics act by interfering with

A) bacterial cell wall synthesis.
B) the uptake of bacteria.
C) bacterial cell division.
D) bacterial chromosome replication.
E) the ability of the bacteria to avoid the host's immune system.

Question 11

What percentage of people carry antibiotic resistant strains of Staphylococcus aureus on their skin or in their noses?

A) about 1%
B) about 5%
C) about 10%
D) about 12%
E) about 30%

Question 12

Which of the following people is/are especially vulnerable to illness caused by drug-resistant bacteria?

A) a 3-month-old baby
B) a 90-year-old man
C) an athlete with several cuts on his arms and legs
D) a person with pneumonia
E) All of the above people are especially vulnerable.

Question 13

If a person has a compromised immune system,why might they want to avoid seeking treatment at a hospital?

Question 14

MRSA can be contracted by

A) skin-to-skin contact.
B) contact with open wounds.
C) contact with contaminated surfaces.
D) contact with contaminated soap and towels.
E) All of the above.

Question 15

Staphylococcus aureus is a type of

A) pathogenic spore.
B) virus.
C) bacteria.
D) fungi.
E) pathogenic fungi.

Question 16

If the cell wall of Staphylococcus aureus fails to form properly,water will enter the cell

A) by the process of osmosis.
B) by the process of imbibition.
C) by active transport.
D) to destroy the bacterial DNA.
E) to help maintain the cell's turgor pressure.

Question 17

Which of the following is NOT a possible way of transmitting a Staphylococcus aureus infection?

A) sharing towels
B) skin-to-skin contact
C) contact sports
D) inhalation
E) All of the above ARE possible methods.

Question 18

Staphylococcus aureus can cause

A) boils.
B) sores.
C) pimples.
D) death.
E) All of the above.

Question 19

MRSA should routinely be treated with

A) penicillin.
B) a ß-lactam antibiotic.
C) cephalosporin.
D) vancomycin.
E) cephalexin.

Question 20

MRSA is caused by

A) Streptococcus aureus.
B) a drug-resistant form of S. aureus.
C) S. aureus USA300.
D) a drug-resistant form of a virus.
E) a drug-resistant form of Methicillin aureus.

Question 21

Which of the following is TRUE of ß-lactams?

A) They prevent transcription.
B) They prevent a cell from acquiring nutrients.
C) They prevent a cell from reproducing.
D) They prevent a cell from making ATP.
E) They cause a cell to burst open.

Question 22

Which of the following is TRUE of ß-lactams?

A) They are only prescribed for the most drug-resistant forms of Staphylococcus aureus.
B) They cause a cell to burst open from water pressure.
C) Vancomycin is one of the most effective ß-lactams.
D) They must be administered with caution because they can damage human tissues with prolonged use.
E) They are one of the few classes of drugs that are effective against both bacteria and viruses.

Question 23

Bacteria usually reproduce by

A) meiosis.
B) sexual reproduction.
C) binary fission.
D) binary fusion.
E) transformation.

Question 24

A bacterial strain divides once every 30 minutes.After 90 minutes,a single bacterium can form a total of ___ bacteria.

A) 3.
B) 6.
C) 8.
D) 16.
E) This answer cannot be calculated from the information given.

Question 25

If a bacterium susceptible to ß-lactam antibiotics were placed in an isotonic solution and exposed to the antibiotics,

A) its cell wall would rupture and burst due to the influx of water caused by osmosis.
B) its cell membrane would rupture and burst due to the influx of water caused by osmosis, but its cell wall would remain intact.
C) osmosis would drive water out of the cell, causing it to shrivel and die due to lack of internal fluids.
D) it would remain intact because osmosis would cause no change in water flow into or out of the cell.
E) it would remain intact because the cell wall is strong enough to withstand the pressure caused when osmosis draws water into the cell.

Question 26

What is the drug of choice when a patient has a severe drug-resistant infection?

A) penicillin
B) methicillin
C) vancomycin
D) cephalexin
E) amoxicillin

Question 27

Each bacteria cell typically splits into ____ new cells.

A) 2
B) 3
C) 4
D) 8
E) 20

Question 28

Describe how ß-lactams function to kill bacteria.Be specific not only about what they do but also about the results.

Question 29

Binary fission is a form of

A) nuclear division.
B) aerobic reproduction.
C) anaerobic reproduction.
D) asexual reproduction.
E) sexual reproduction.

Question 30

If bacterial cells can divide every 20 minutes,how many bacteria will be present after 2 hours if the starting population is 100 cells?

A) 700
B) 1200
C) 1300
D) 3200
E) 6400

Question 31

Which of the following is TRUE of bacterial reproduction?

A) The daughter cells are identical to the parent cell.
B) One cell divides to produce four cells.
C) Reproduction is sexual and thus allows for genetic diversity in the new cells.
D) It takes 24 hours for a bacterial population to double in size.
E) Bacterial reproduction is called binary fusion.

Question 32

Bacteria can divide as often as once every

A) 3 hours.
B) minute.
C) hour.
D) day.
E) 20 minutes.

Question 33

The severity of a bacterial infection is related to

A) the health of the patient.
B) whether the bacteria produce toxins.
C) whether the bacteria have a way to avoid the immune system.
D) which part of the body is infected.
E) All of the above.

Question 34

Explain how interfering with cell wall production could kill Staphylococcus aureus.

Question 35

Why doesn't a ß-lactam antibiotic prevent the growth of new host (human)cells?

Question 36

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

A) one that changes one of the proteins on the cell membrane
B) one that interferes with cell membrane synthesis
C) one that enhances DNA replication
D) one that strengthens bacterial cell walls
E) one that enhances protein synthesis

Question 37

Bacteria reproduce by a process called

A) cellular bifurcation.
B) cleavage.
C) bipolarization.
D) binary fission.
E) divergent fusion.

Question 38

Bacteria lack meiosis.Explain how they produce offspring without meiosis.

Question 39

Why doesn't a ß-lactam antibiotic prevent the growth of new host (human)cells?

A) The host cells are slowed down by the antibiotic, but still grow faster than the bacteria.
B) The host cells are protected by a thick layer of cell wall peptidoglycan.
C) Osmosis only occurs in bacterial cells, never in human or animal cells.
D) The antibiotic only harms bacterial cell walls; the host cells do not have cell walls.
E) Antibiotics slow host cell growth, but after the bacteria are dead and the antibiotics are removed, the host cells can grow again.

Question 40

After bacterial asexual reproduction,the daughter cells produced

A) are identical to each other.
B) have half the chromosome number.
C) are genetically different.
D) have double the DNA content.
E) exchange genes by transformation

Question 41

What is gene transfer?

Question 42

If a man fathers a child at 20 years of age,the DNA that was passed on to the child was created 20 years after the zygote that created the man.How many generations of bacteria could be formed in that same 20 years (ignore leap years)? How many more chances of mutation would the bacterial DNA have?

Question 43

A population is described as

A) all the members of the same species located on a continent.
B) the species that live in a geographic area.
C) all the species occupying a specific locale.
D) all the members of the same species living in the same area.
E) the species richness.

Question 44

Do you think drug resistance is more likely to develop in a species of bacteria that can double its population every 20 minutes or a species that doubles its population every 24 hours? Explain your answer.

Question 45

Five different strains of bacterial cultures were grown overnight in a medium containing antibiotics.Of the resulting population densities listed below,which was the most fit?

A) 5 x 10⁵ cells/ml
B) 6 x 10⁶ cells/ml
C) 7.5 x 10⁷ cells/ml
D) 0.075 x 10⁸ cells/ml
E) 5 x 10⁷ cells/ml

Question 46

A highly resistant antibiotic strain of S.aureus would reproduce best in

A) the presence of antibiotic.
B) the absence of antibiotic.
C) the presence or absence of antibiotic.
D) a moderate concentration of antibiotic.
E) a fluctuating concentration of antibiotic

Question 47

Drug-resistant populations of bacterial stains are a result of

A) fast bacterial doubling time outpacing typical drug doses.
B) drugs or other selective environmental pressures.
C) binary fission.
D) manipulations in the lab to create new strains for research.
E) transmission from an infected person.

Question 48

Bacterial cell division is known as

A) friction.
B) cytofission.
C) fusion.
D) fission.
E) nuclear fission.

Question 49

Your friend has contracted a bacterial infection.Which of the following hypothetical drugs would you suggest as the best way to prevent an antibiotic-resistant allele from arising and spreading throughout the bacterial population in her body?

A) a drug that prevents mutations but allows gene swapping
B) a drug that doesn't prevent mutations, but does prevent gene swapping with individuals of its own species
C) a drug that doesn't prevent mutations, but does prevent gene swapping with individuals of other species
D) a drug that doesn't prevent mutations, but prevents gene swapping with any individual of any species
E) a drug that prevents both mutations and gene swapping

Question 50

Drug resistance may take which of the following forms?

A) Bacteria may produce ß-lactamases.
B) Bacteria may produce proteins that can disable antibiotics.
C) Bacteria may produce proteins with altered shapes that antibiotics can no longer bind to.
D) All of the above.
E) None of the above.

Question 51

A bacterial strain will most likely become antibiotic resistant when it is grown in

A) high heat.
B) extreme cold.
C) the presence an acidic environment.
D) the presence of MRSA.
E) a laboratory that researches viruses.

Question 52

Assume that every time you copy DNA,whether it is bacterial DNA or human DNA,you have the same rate of mutation.If that is the case,explain why bacteria mutate to adapt to their environment much faster than humans.

Question 53

A bacterium has a gene that creates a ß-lactamase enzyme.It passed that gene to another bacterium it encounters.What is the result of that gene transfer?

Question 54

Which bacterial phenotype would have the highest fitness if it were cultured in a medium containing antibiotics?

A) a slightly antibiotic-resistant variant
B) a moderately antibiotic-resistant variant
C) a highly antibiotic-resistant variant
D) an antibiotic-sensitive variant
E) all phenotypes have equal fitness

Question 55

Which of the following factors will NOT influence the rate at which drug resistance can evolve in a population of bacteria?

A) mutation rate
B) the frequency of gene swapping with members of the same species
C) the frequency of gene swapping with members of different species
D) the frequency of reproduction
E) the age of the host

Question 56

What are the two mechanisms by which a bacterial cell can become resistant to antibiotics?

Question 57

Overprescription of antibiotics and their improper use is a cause of

A) a decrease in drug-resistant species.
B) elimination of drug-resistant species.
C) a rise in drug-resistant bacterial populations.
D) keeping the level of MRSA infections stable.
E) decreasing MRSA levels in hospitals.

Question 58

What is responsible for genetic variation in bacteria?

A) mutations in the genome during binary fission
B) gene influx from a different bacterial strain
C) DNA influx from the environment
D) gene transfer from the same bacterial species
E) All of the above.

Question 59

All the individuals of a species living in a specific area compose a

A) colony.
B) species.
C) community.
D) population.
E) clade.

Question 60

How would the resistance level of an antibiotic-sensitive variant in culture medium containing a minimal amount of antibiotics change over time?

A) resistance will remain low
B) resistance will remain medium
C) resistance will remain high
D) resistance will change from high, to medium, and finally low
E) resistance will change from low, to medium, and finally high

Question 61

What is the role of natural selection in evolution?

Question 62

A number of mosquito populations today are resistant to specific insecticides,even though those insecticides were highly effective when they were first introduced.Biologists believe that insecticide resistance evolved in mosquitoes because

A) individual mosquitoes built up an immunity to an insecticide after being exposed to it.
B) mosquitoes needed to develop insecticide resistance to survive after the insecticide was used.
C) a few mosquitoes were probably resistant to the insecticide before it was ever used. These survived and passed that trait on to their offspring.
D) the presence of the insecticide caused some mosquitoes to develop resistance; they survived and passed the trait to their offspring.
E) current mosquito populations are phenotypically variable and exhibit differential fitness in different environments.

Question 63

Natural selection causes

A) changes in an individual's genes.
B) changes in allele frequencies within a population.
C) a decrease in reproductive fitness in a population.
D) the inheritance of acquired characteristics.
E) changes in the mechanism of inheritance.

Question 64

Which has made the biggest impact on future generations?

A) a 5000-year-old bristlecone pine tree that produced 1 offspring every 100 years
B) a 5000-year-old bristlecone pine tree that produced 3 offspring every 100 years
C) a 3000-year-old bristlecone pine tree that produced 100 offspring every 100 years
D) a 2000-year-old bristlecone pine tree that produced 100 offspring every 10 years
E) a 500-year-old bristlecone pine tree that produced 100 offspring every year

Question 65

An organism's ability to survive and reproduce is called the organism's

A) natural selectivity.
B) advantage.
C) phenotype.
D) genotype.
E) fitness.

Question 66

You've gone to the doctor and she has determined that you have a Staphylococcus aureus infection,and it is one of the following possible strains (A-E),but she is not sure which.Which antibiotic is most likely to be effective?

Question 67

Which of these are most fit in a sauna or jacuzzi? Which of these would be more likely to be transferred between humans in these locations.Explain.(Note: More than one bacterium may be correct.)

Question 68

Which of these strains of bacteria (A-E)is most fit in a hospital situation? Explain.

Question 69

What would the outcome be if an antibiotic-sensitive homogeneous (no variation)strain of S.aureus was grown in the presence of antibiotics?

A) cell growth that begins slowly but proceeds rapidly
B) rapid mutation and growth
C) no cell growth
D) eventual rise of antibiotic-resistant cells
E) rapid growth then sudden death

Question 70

What would the outcome be if a homogeneous (no variation)antibiotic-sensitive strain of S.aureus was grown in the presence of antibiotics? Why?

Question 71

Which of these bacteria (A-E)are LEAST fit in a forest situation? Explain.(Note: More than one bacterium may be correct.)

Question 72

All of the following are true of natural selection,EXCEPT

A) it works best in genetically uniform populations.
B) it results in populations better suited to their environment than their predecessors.
C) it is the process by which evolution occurs.
D) it results in some individuals surviving better and reproducing more than others.
E) it results in a change in allele frequencies over time.

Question 73

You have a population of boa constrictors on a Caribbean island that is 100 square miles and has a rich supply of lizard,bird,and mammal prey,and the island lacks boa constrictor predators (including humans).The boas are capable of reaching 16 feet in length in these conditions.Overall boa growth is strongly linked to habitat size and food availability.A hurricane comes along and moves 18 pregnant female boas to three different islands (6/island).
Island A is 10 square miles,has no mammal or bird prey,has three sizeable human settlements,and is farmed extensively.
Island B is 30 square miles,has a lot of mammal,bird,and lizard prey items and very few humans.
Island C is 50 square miles,has limited bird prey,no mammal prey items,and moderate small lizard prey items.
After 100 years,on which of these three islands would you expect to find the smallest boas?

Question 74

Two bacteria are genetically identical in all ways except that one has a gene that confers resistance to penicillin.These two cells are grown in the laboratory in cell-culture medium that is free of antibiotics.Will one cell reproduce faster than the other one? If so,which one? Explain your answer.

Question 75

Describe the relationship between an organism’s genotype, phenotype, environment, and natural selection.

Question 76

All of the following are true of evolution,EXCEPT

A) evolution leads to individuals with higher fitness than their predecessors.
B) individuals adapt their genes to improve survival.
C) the environment plays a large role in the process of evolution.
D) individuals with the most adaptive phenotypes have the most offspring.
E) evolution works through natural selection.

Question 77

Which of the following is more fit?

A) a 5000-year-old bristlecone pine tree that produced 1 offspring every 100 years
B) a 5000-year-old bristlecone pine tree that produced 3 offspring every 100 years
C) a 3000-year-old bristlecone pine tree that produced 100 offspring every 100 years
D) a 2000-year-old bristlecone pine tree that produced 100 offspring every 10 years
E) a 500-year-old bristlecone pine tree that produced 100 offspring every year

Question 78

A species of small lizard has three color forms: pale gray,brown,and black.In its original range,the colors of the rocky environment were mixed from pale gray to very dark,and the population had an even mix of all three color forms.The blending of colors with the environment helps the lizards hide from predators.A group of these lizards ended up on an island with all gray rocks,and the island has no predators that eat lizards.What will the lizards look like in 50 years?

Question 79

You have a population of boa constrictors (snakes)on a Caribbean island that is 100 square miles and has a rich supply of lizard,bird,and mammal prey,and the island lacks boa constrictor predators (including humans).The boas are capable of reaching 16 feet in length in these conditions.Overall boa growth is strongly linked to habitat size and food availability.A hurricane comes along and moves 18 pregnant female boas to three different islands (6/island).
Island A is 10 square miles,has no mammal or bird prey,has three sizeable human settlements,and is farmed extensively.
Island B is 30 square miles,has a lot of mammal,bird,and lizard prey items and very few humans.
Island C is 50 square miles,has limited bird prey,no mammal prey items,and moderate small lizard prey items.
After 100 years,on which of these three islands would you expect to find the largest boas?

Question 80

Which is necessary for natural selection to proceed?

A) variation within a population
B) a mechanism of inheritance
C) acquisition of adaptations
D) generations reproducing over time
E) All of the above.