Immune system

Question 1

ELISA test

Answer 1

Antibody binds to complementary antigen
Add antibody with enzyme attached to cells/DNA
Second antibody attaches to antigen
Wash to remove excess antibody
Add substrate to cause colour change

Question 2

The immune response summary

Answer 2

More T helper cells
Lower viral load to cause infection
More activation of B cells
So more production of plasma cells and antibodies
More pathogens destroyed

Question 3

Phagocytosis

Answer 3

Phagocyte engulfs pathogen
Forming phagosome and fuses with lysosome
Lysozymes hydrolyse pathogen
Pathogen antigens are presented on the phagocytes cell surface membrane

Question 4

Viral replication

Answer 4

Attachment proteins on the virus attach to receptors on host cell
Virus injects its RNA
RNA converted to DNA using reverse transcriptase
DNA transcribed into mRNA
DNA incorporates into (T) helper cell
Viral DNA replicates and makes viral proteins

Question 5

What is an antibody?

Answer 5

A protein that binds to a specific antigen

Question 6

Herd immunity population requirements

Answer 6

The basis of widescale vaccination programmes
If the disease is highly contagious over 90% of the population should be vaccinated
If less contagious only over 80%
Offers protection to the most vulnerable in a population like babies and the elderly

Question 7

What is passive immunity?

Answer 7

Can be natural or artificial
It’s where an individual receives antibodies from an external source

Question 8

What is active immunity?

Answer 8

Can be natural or artificial
Where an individual has made its own antibodies