Adaptation and Selection

Question 1

Bacterial genetic variation

Answer 1

Adapt through mutation or conjugation, easily develop antibiotic resistance.

Question 2

Mutations

Answer 2

Changes to DNA alter proteins and so an organism’s characteristics

Question 3

Conjugation

Answer 3

One cell produces a thin projection which meets another cell, and forms a conjugation tube
The donor cell replicates one of its plasmids, which is broken so it becomes linear.
Cell contact is brief so only a bit of the plasmid transfers.
This forms a new plasmid in the recipient cell, which acquires some of the characteristics.

Question 4

How antibiotics work

Answer 4

Preventing bacteria from forming a cell wall makes them unable to prevent water entering, and so osmotic lysis occurs. These antibiotics are only effective when the bacteria is growing.

Question 5

Antibiotic resistance- penicillin

Answer 5

A mutation resulting in a new protein which was an enzyme to penicillin. It is now called penicillinase. Mutations are rare and not always advantageous.

Question 6

Vertical gene transmission

Answer 6

Passed from one generation to the next

Question 7

Horizontal gene transmission

Answer 7

Conjugation

Question 8

TB antibiotic resistance

Answer 8

It is a long course of antibiotics which many people don’t finish. This leaves all the resistant bacteria to divide and multiply. A cocktail of 3-4 antibiotics must now be used to counter strains resistant to multiple antibiotics.

Question 9

MRSA- presence in hospitals

Answer 9

Those in hospital are generally immuno-compromised anyway
Lot of people in cramped conditions, with nurses/doctors who visit many patients
Developed multiple resistance due to antibiotic use in hospitals being high