Pathogens

Question 1

Antigenic Drift:

Answer 1

Antigens are different enough that immune system no longer recognises them

• Small change in one protein (often a point mutation)
• Antibodies are less effective

Question 2

Antigenic Shift:

Answer 2

If two strains with different antigens infect the same host at the same time, it can form a new virus

• Whole sections of genome swapped; widespread change

Question 3

Vertical Gene Transfer

Answer 3

When genes are transferred down generations
i.e. parent to offspring

Question 4

Horizontal Gene Transfer

Answer 4

When genes are transferred across from an individual to another.
- Not due to reproduction

i.e. bacteria transferring resistant plasmids to other bacteria