4.1.13 Evolution of Resistance

Question 1

What is drug resistance in microorganisms

Answer 1

• Variation caused by mutations in bacteria population
• When treated with antibiotics, the bacteria does not die
• Mutation may change in an existing gene within the bacterial genome, which gives rise to a new nucleotide sequence coding for a different protein which is not affected by the antibiotic being used
• Resistant bacteria grows and reproduces with less competition because the non-resistant ones die
• So resistant genes are passed on in multiple generations
• Whole generation becomes antibiotic resistant
• natural selection

Question 2

How can bacteria inherit antibiotic resistance?

Answer 2

• Vertical transmission (asexual reproduction by binary fission passes down alleles onto next generations)
• Horizontal transmission (plasmids containing resistant alleles are transferred between bacteria, occurring during CONJUGATION, so antibiotic resistance can spread between bacterial populations)

Question 3

What causes drug resistance in microbes (human error)?

Answer 3

• Overuse of antibiotics
• Treatment of non-serious infections
• Treatment of animals in agriculture
• Not finishing course of antibiotics

Question 4

How can antibiotic resistance be reduced?

Answer 4

• Only prescribing antibiotics when absolutely necessary
• Make sure patient finishes course of antibiotics
• More research into new antibiotics
• Use a different antibiotic

Question 5

How does pesticide resistance in insects work

Answer 5

• Pesticides are chemicals that kill pests
• We use them to control pests that damage human food crops or kill vectors of disease
• Insecticides for example are sprayed on crops and act as selective agents, which is an environmental factor influencing the changes of survival of particular species so drives natural selection
• So any insect with a mutation with resistance to the insecticide will pass on these alleles to future generations