immunity exam questions Flashcards
describe the role of lysosomes in the defence against disease (2)
-contain hydrolytic enzymes
-which digest bacteria
describe what is happening at stage 1 (2)
-formation of vesicle
-derived from plasma membrane
what are monoclonal antibodies? (1)
-antibodies produced from a single type of B cell/plasma cellthe
the tests using MCAB allow vets to dientifyt brucellosis while tehy are still on a farm. Explain teh advantage of this (3)
-fast so rapid treatment of animals
-can be isolated
-reduced spread of disease
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))
-don’t know number orf helper T cells
-would need to look at symptoms
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)
-baby gets maternal antibodies
-so will always test positive.
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)
-shows that enzyme is causing colour change
-washing is effective
t test
looking at difference berween two means
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)
-virus cannot enter cell
-so cannot replicate
a high mutation raqte makes it difficult to develop a vaccine (3)
vaccine contains antigens
antigen changes shape
antibody no longer complimentary.
explain how a blood transfusion from a patient recently recovered from ebola may be an effective treatment (3)
-high conentration of antibody
-transfusion contains antibodies
antibodies will bind to antigen
virus destroyed
suggest two reasons why the perentage of infants vaccinated dereazsed between 1973-1975
-reduced risk of side effects
-reduced spread of whooping cough.
) 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)
some people allergic
so they cannto take it
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)
-prevents DNA replication
affects T cells more as they cannot recycle cytokines
fewer cytokines produced.
Suggest how gel electrophoresis separated the proteins obtained from the synapses. (2)
-depends on mass
-depends on charge
Each type of labelled antibody binds specifically to one of the proteins.
Explain why.
___________________________________________________________________
(3)
each protein has a different tertiary structure
antigen has specific variable region
so forms different antigen antibody comple
) 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)
scienists cannot show bias
volunteers cannot show placebo effect.
Explain how a blood transfusion from a patient recently recovered from Ebola may be an effective treatment (lines 8–10).
-recently recovered person has many antibodies
-antibodies in transfusion
-antibodies bind to antigens
-virus destroyed/cannot enter cell
) 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)_
different volumes of blood
differing amounts of nicotine
Some people have suggested that this vaccine should not be given free to smokers on the National Health Service (NHS). Evaluate this suggestion
people choose to smoke/know the risks
should spend this moeny on education
) 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)
-infected by pathogens
-produce toxins
-destroy cells
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)
HIV enters cells before antibodies can bind
antibodies cannot enter cells
