immune system mark schemes

Question 1

describe how hiv is replicated

Answer 1

1) the virus attaches to the complementary receptor on the host cell(t helper cell)
2)injects nucleic acid
3)RNA traversed to dna with reverse transcriptase
4) viral protein produced
5)virus assembled

Question 2

give other types of pathogen that can stimulate a immune response

Answer 2

-transplats
-cancer cells

Question 3

What’s the purpose of a disulphide bridge

Answer 3

bonds two polypeptide chains together

Question 4

how do viruses infect other species of frog

Answer 4

• viral dna is always mutating and
  -altered tertiary structure of attachment protein

Question 5

determining the genome of the viruses could help scientists to develop a vaccine how ?

Answer 5

-all genetic info of virus
- would know the dna
-woud know all base sequence which could identify proteins which make genetic code

Question 6

Describe the role of t helper cells

Answer 6

1) phagocytosis happens and they become antigen presenting cells
2) the complementary t helper cells binds to this by its receptor
3) this stimulates the t helper cell to be divided by motisis

-this helps b cells to be produced
-develops into more t helper cells

• they dont contain antibodies

Question 7

Describe process of b lymphocytes

Answer 7

1) they secrete a small amount of antibody onto their membrane
2) the complimentary antigen binds
3) t helper cell causes b to divide by motisis
4)this creates plasma cells
5) produces antibodies and memory cells

Question 8

Describe the structure of antibodies

Answer 8

• has2 heavy and 2 light chains
  -the 2 heavy chains have variable region where different amino sequence for more than one type of antibody
  -variable has 2 attachment sites
  -attatches to antigen to form antibody- antigen complex
  -stimulates by b lymphocytes

Question 9

describe an antigen

Answer 9

-foreign proteins
-stimulate an immune response

Question 10

what two things stimulate immune response

Answer 10

-vaccination
-antigen

Question 11

Describe how and what vaccines do

Answer 11

• weakened strains of virus
  -activate production of b lymphocytes

Question 12

high blood pressure leads to an accumulation of tissue fluid how ?

Answer 12

-high blood pressure = high hydrostatic pressure
- forces water out
-more tissue fluid formed.