immunity exam questions

Question 1

describe the role of lysosomes in the defence against disease (2)

Answer 1

-contain hydrolytic enzymes
-which digest bacteria

Question 2

describe what is happening at stage 1 (2)

Answer 2

-formation of vesicle
-derived from plasma membrane

Question 4

what are monoclonal antibodies? (1)

Answer 4

-antibodies produced from a single type of B cell/plasma cellthe

Question 5

the tests using MCAB allow vets to dientifyt brucellosis while tehy are still on a farm. Explain teh advantage of this (3)

Answer 5

-fast so rapid treatment of animals
-can be isolated
-reduced spread of disease

Question 6

this test only dtects the presence of HIV antibodies. give 2 reasons why it cannot be used to find out if a person has AIDS (2))

Answer 6

-don’t know number orf helper T cells
-would need to look at symptoms

Question 7

a mother who was infected with HIV gave birth to a baby. The baby tested positive using this test. this does not prove that the baby is infected with HIV.
Explain why (2)

Answer 7

-baby gets maternal antibodies
-so will always test positive.

Question 8

a control well is set up every time this test is used. This is treated in exaactly the same way as the test wells except that blood plasma is replaced by a salt soliton
use info from the figure to suggest 2 purposes of the control well (2)

Answer 8

-shows that enzyme is causing colour change
-washing is effective

Question 9

t test

Answer 9

looking at difference berween two means

Question 10

people who dont have the specific receptor protein in their cell surface membrane may be infected with the ebola virus but do not develop the disease,
explain why they do not develop the disease (2)

Answer 10

-virus cannot enter cell
-so cannot replicate

Question 11

a high mutation raqte makes it difficult to develop a vaccine (3)

Answer 11

vaccine contains antigens
antigen changes shape
antibody no longer complimentary.

Question 12

explain how a blood transfusion from a patient recently recovered from ebola may be an effective treatment (3)

Answer 12

-high conentration of antibody
-transfusion contains antibodies
antibodies will bind to antigen
virus destroyed

Question 13

suggest two reasons why the perentage of infants vaccinated dereazsed between 1973-1975

Answer 13

-reduced risk of side effects
-reduced spread of whooping cough.

Question 14

) Suggest why 5-ASA is only effective in controlling the swelling of the lining of the intestines in some people with Crohn’s disease (lines 11–12). (2)

Answer 14

some people allergic
so they cannto take it

Question 15

Suggest why 6-MP can be used to control the symptoms of Crohn’s disease (lines 13–15).
Do not include details of enzyme inhibition or protein synthesis in your answer. (3)

Answer 15

-prevents DNA replication
affects T cells more as they cannot recycle cytokines
fewer cytokines produced.

Question 16

Suggest how gel electrophoresis separated the proteins obtained from the synapses. (2)

Answer 16

-depends on mass
-depends on charge

Question 17

Each type of labelled antibody binds specifically to one of the proteins.
Explain why.
___________________________________________________________________
(3)

Answer 17

each protein has a different tertiary structure
antigen has specific variable region
so forms different antigen antibody comple

Question 18

) In this investigation, neither the volunteers nor the scientists knew if a particular volunteer was receiving the vaccine or a placebo.
Suggest two reasons why this made the scientists’ results more reliable.
1. ____________________________________________________________
(2)

Answer 18

scienists cannot show bias
volunteers cannot show placebo effect.

Question 18

Explain how a blood transfusion from a patient recently recovered from Ebola may be an effective treatment (lines 8–10).

Answer 18

-recently recovered person has many antibodies
-antibodies in transfusion
-antibodies bind to antigens
-virus destroyed/cannot enter cell

Question 19

) The scientists measured the concentration of nicotine in the blood of two volunteers who smoked the same number of cigarettes per day.
Suggest two reasons why the concentration of nicotine in the blood of these smokers might be different.
1. ____________________________________________________________
(2)_

Answer 19

different volumes of blood
differing amounts of nicotine

Question 20

Some people have suggested that this vaccine should not be given free to smokers on the National Health Service (NHS). Evaluate this suggestion

Answer 20

people choose to smoke/know the risks
should spend this moeny on education

Question 21

) People with AIDS die because they are unable to produce an immune response to pathogens (lines 2-4).
Explain why this leads to death.
(3)

Answer 21

-infected by pathogens
-produce toxins
-destroy cells

Question 22

Explain why each of the following means that a vaccine might not be effective against HIV.
(i) HIV rapidly enters host cells (lines 6-7). (2)

Answer 22

HIV enters cells before antibodies can bind
antibodies cannot enter cells