Infection and the Immune System

Question 1

Explain how changes in blood vessels result in redness and swelling at site of inflammation. (4)

Answer 1

• histamine released
• causing vasodilation

^ increased blood flow

^ causing blood plasma to enter tissues causing swelling

Question 2

Describe how HIV can enter T-helper cells. (3)

Answer 2

• glycoproteins on virus surface

^ bind to receptors on t-helper cell surface

^ viral RNA enters cell

Question 3

Explain why destruction of t-helper cells causes AIDS symptoms. (4)

Answer 3

• reduces cytokine production

^ reduces activation of B cells

^ reduced antibody production

• therefore increased risk of oportunistic infections

Question 4

Which cell produces antibodies? (1)

Answer 4

plasma cell

Question 5

Explain why stem cells may prevent HIV causing AIDS. (4)

Answer 5

• stem cells can differ. into specialised cells

^ like HIV-resistant T-helper cells

• mutated receptor prevents HIV entering T-helper cells
• T-helper cell isnt destroyed so AIDS cannot develop

Question 6

Define: bacteriostatic antibiotic. (1)

Answer 6

• substance which can prevent bacteria multiplying

Question 7

Compare and contrast Ebola and HIV. (3)

Answer 7

• both: RNA
• both: glycoproteins
• HIV = spherical , Ebola = elongated