Cell recongition

Question 1

How can different molecules be detected on an cells

Answer 1

Their 3D tertiary structure

Question 2

What is an antigen

Answer 2

Molecules that generate an immune response by lymphocyte cells

Question 3

What will happen if a mutation occurs in the gene thag codes for the antigen

Answer 3

The shape of the antigen will change

Question 4

What happens when the shape of an antigen changes

Answer 4

Any previous immunity is no longer effective and all the memory cells will remember the old shape so will not work

Question 5

Describe the process of phagocytes

Answer 5

Non specific response
The receptors on the surface of the phagocyte will attach to chemicals/antigens
The phagocyte changes shape and engulfs the pathogen
The pathogen is contained in a phagosome vesicle
A lysosome fuses with the phagosome and release lysozymes which hydrolyse the pathogen
This destroyes the pathogen

Question 6

What are lymphocytes

Answer 6

White blood cells involved in the specific immune response

Question 7

What is the cell mediated response

Answer 7

Once a pathogen has been destroyed it’s antigens are presented on the surface
Helper T cells have receptors on their surface that attach to the antigens on the antigen presenting cells
This activates helper T cells to divide by mitosis and to replicate to make clones which differentiate into different types of T cells

Question 8

What are the types of differentiated cells that clones T helper cells differentiate into

Answer 8

T helper cells - activate B lymphocytes
Macrophages - for phagocytosis
Memory cells
Killer T cells - cytotoxic

Question 9

What do Killer t cells do

Answer 9

Destroy abonormal of infected cells

Question 10

Are antibodies soluble or insoluble

Answer 10

Soluble

Question 11

What is the humoral response

Answer 11

• B cell is triggered when encountering its antigen
• It takes in the antigen that endocytosus and presents it on its surface
• When the B fell collided with helle T cell it activates it to go through clonal selection
• The b cells undergo mitosis and make large number of cells which differentiate into plasma cells/ memory b cells

Question 12

Structure of antibody

Answer 12

Quatnernary structure
4 polypeptide chains

Question 13

What is passive immunity

Answer 13

The antibodies are introduced to the body

Question 14

What is active immunity

Answer 14

Immunity created by your own immune system following exposure to pathogen or antigen

Question 15

What is NATURAL active immunity

Answer 15

Following infection and the body creates its own antibodies and memory

Question 16

What is artificial active immunity

Answer 16

Introduction of a weak pathogen or antigen via a vaccine

Question 17

What is herd immunity

Answer 17

If enough of the population is vaccinated the pathogen cannot easily be spread amongst the population

Question 18

How does HIV replicate in Helper T cells

Answer 18

The T cells have CD4 protein which HIV attaches too
The HIV protein capsule fuses to the helper T cell and allows the RNA and enzymes from HIV to enter
The HIV enzyme reverse transcriptase copes the RNA into DNA copy and moved it the the Helper t cell nucleus

Question 19

What is AIDS

Answer 19

When replication viruses in the helper T cell interfere with the immune system

Question 20

What is monoclonal antibody

Answer 20

A antibody that can be isolated and cloned

Question 21

When is it used

Answer 21

Pregnancy tests
Medical treatment/ diagnosis

Question 22

What can monoclonal antibodies do

Answer 22

They have a binding site complementary to the antigens on the outside of the cell
The antibodies attach to the cell

Question 23

What is the ELISA test

Answer 23

First mobile antibody ( complementary to the antigen tested for )
Second antibody which is conplemsgeh but is immobilised
Third antibody is immobilised and is complementary to the first antibody
Add test sample to the beaker
Wash to remove ant unbound test sample
Add first antibody
Wash
Add second antibody