2.5d - Defence Against Parasitic Attack

Question 1

Immune response in mammals has both…

Answer 1

non-specific and specific aspects

Question 2

Non-specific defences:

Answer 2

• physical barriers
• chemical secretions
• inflammatory response
• phagocytes
• natural killer cells destroying cells infected with viruses

Question 3

Specific cellular defences:

Answer 3

• a range of white blood cells constantly circulate, monitoring the tissues
• if tissues become damaged or invaded, cells release cytokines that increase blood flow resulting in non-specific and specific white blood cells accumulating at the site of infection or tissue damage

Question 4

Mammals contain…

Answer 4

many different lymphocytes, each possessing a receptor on its surface, which can potentially recognise a parasite antigen

Question 5

Some selected lymphocytes…

Answer 5

will produce antibodies, others can induce apoptosis in parasite-infected cells

Question 6

Antibodies possess regions where…

Answer 6

the amino acid sequence varies greatly between different antibodies

Question 7

Antibodies variable regions give…

Answer 7

the antibody its specificity for binding antigen

Question 8

When the antigen binds to a variable region binding site….

Answer 8

the antigen-antibody complex formed can result in inactivation of the parasite, rendering it susceptible to a phagocyte, or can stimulate a response that results in cell lysis, memory lymphocyte cells are also formed

Question 9

Initial antigen exposure produces…

Answer 9

memory lymphocyte cells specific for that antigen that can produce a secondary response when the same antigen enters the body in the future

Question 10

When a secondary response to the same antigen entering the body occurs…

Answer 10

antibody production is enhanced in terms of speed of production, concentration in the blood and duration