6.7 We are not Winning the Race

Question 1

Why do bacterial populations evolve very quickly?

Answer 1

1. Bacteria produce very fast.
2. Bacterial population sizes are usually in billions so the number the cells containing mutations are vast.
3. Some random mutations will be advantageous to the cell containing them.

Bacterial with a useful mutation are more likely to survive reproduce and spread.

Question 2

What surprisingly acts a selection pressure to the bacteria?

Answer 2

The human immune system therefore it encourages there to be bacterial strategies for evading or disabling the immune system.

Question 3

What do Antibiotics do?

Answer 3

Provide another selection pressure.

Question 4

What can be the effect of mutations on antibiotics

Answer 4

Mutations that arise in pathogenic bacteria can make them resistant to antibiotics.

Question 5

What can the bacteria produce that can effect the antibiotic?

Answer 5

The bacteria can produce an enzyme that enables the cell to break down the antibiotic.

Question 6

What can the bacteria also do to ensure that the antibiotic is ineffective?

Answer 6

They may use a different metabolic pathway for the reactions inhibited by the antibiotic.

Question 7

If the antibiotic is absent why may the bacteria with the mutation be at a disadvantage?

Answer 7

1. May reproduce more slowly using resources to produce enzymes that under ‘normal’ circumstances (no antibiotic present) are not required.

Question 8

What happens to bacteria with the advantageous gene.

Answer 8

1. They survive, grow and reproduce and the frequency of the gene for resistance within the bacterial population will increase.

Question 9

Why is the passing of advantageous gene called vertical evolution?

Answer 9

Advantageous gene is bassed vertically from one generation to the next.

Question 10

What is horizontal evolution?

Answer 10

When the gene is passed from one bacterium to another which may be of the same or different bacterial specicies.

Question 11

What cell-to cell contact process do bacteria undergo instead of sexual reproduction like most animals?

Answer 11

Conjugation.

Question 12

Conjugation (3)

Answer 12

1. Plasmid carrying gene for antibiotic resistance.
2. One strand of the plasmid DNA transfers between conjugating bacteria. Each bacterium replicates the strand to make a complete plasmid.
3. Both bacteria are now resistant.

Question 13

Hospitals

Answer 13

1. Hand wash stations.
2. Signs reminding hospital personnel and visitors to wash their hands.
3. Rules preventing doctors and nurses from wearing ties and watches.

Question 14

How to prevent the development and spread of multiple resistant bacteria

Answer 14

1. Antibiotics should only be used when needed.
2. Patients should complete their treatment even when they feel better so that all the bacteria are destroyed.
3. Infection control should be used in hospitals to prevent bacteria spreading.