antibiotic resistance

Question 1

what is an antibiotic?

Answer 1

a chemical that inhibits the growth of bacteria or kills bacteria, without damaging eukaryotic cells

Question 2

when does antibiotic resistance occur?

Answer 2

as a result of random mutations in bacteria, these occur during DNA replication

Question 3

how does antibiotic resistance develop in a population?

Answer 3

a random mutation occurs which leads to a new allele and a bacteria which is able to produce a protein product that gives it resistance to the antibiotic

there is now variation in the population

when antibiotic is applied there is a selection pressure and differential survival

surviving bacteria go on to reproduce via binary fission

over many generations the freq of the allele for antibiotic resistance will increase as long as the selection pressure is applied

Question 4

what is meant by selection pressure?

Answer 4

a factor in the environment that leads to differential survival

Question 5

what is differential survival?

Answer 5

different individuals with different phenotypes would be more/less likely to survive under certain circumstances

Question 6

suggest some ways bacteria can resist antibiotics?

Answer 6

-modifying target site of antibiotic

-producing new proteins on surface membrane that may lead to hydrolysis of antibiotic

-altering cell membrane permeability to prevent antibiotic entry

-actively pumping antibiotics out of the cell using efflux pumps

-producing enzymes that inactivate antibiotics