Topic 2 - Miss Estruch Immunity

Question 1

What is a cytotoxic T cell?

Answer 1

• They destroy abnormal or infected cells.
• They release a protein, called perforin which embeds in the cell surface membrane and makes a pore so that any substances can either enter or leave the cell this causes cell death.

Question 2

What is the cell mediated response?

Answer 2

1. Once a pathogen has been engulfed and destroyed by a phagocyte the antigens are positioned on the cell surface this is now called an antigen presenting cell.
2. Helper T cells have receptors on their surfaces which can attach to the antigens on the APC.
3. Once attached this activates the helper T cell to divide by mitosis and replicate to make large numbers of clones.
4. Cloned helper T cells activate cytotoxic cells which kill infected body cells they also activate. B cells and memory. T cells for next time.

Question 3

What are B lymphocytes?

Answer 3

White blood cells involved in the specific immune response they are made in the bone marrow and mature in the bone marrow. They are involved in the humoral response.

Question 4

How are B cells activated?

Answer 4

1. They have antibodies on their surface complementary to different antigens.
2. Antigens in the blood collide with their complimentary antibody. The B cell takes in the antigen by endocytosis and presents it on its cell surface membrane.
3. When the B cell collides with a helper T cell receptor this activates the B cell to go through clonal expansion and differentiation.
4. The cells undergo mitosis to make large numbers of cells that differentiate into plasma cells or memory cells and plasma cells make antibodies.

Question 5

What are memory B cells?

Answer 5

Memory B cells can live for decades in your body whereas plasma cells are short lived. They do not make antibodies rather they will divide by mitosis rapidly into plasma cells when they collide with an antigen they have previously encountered. This result in large numbers of antibodies being produced so rapidly the pathogen is destroyed before any symptoms can occur.

Question 6

What is active immunity?

Answer 6

• Immunity created by your own immune system following exposure to the pathogen or its antigen.

Question 7

What is natural active immunity?

Answer 7

Following infection and the creation of the bodies, own antibodies and memory cells.

Question 8

What is artificial active immunity?

Answer 8

Following the introduction of a weakened version of the pathogen or antigens via a vaccine.

Question 9

What is introduced into the body during a vaccination?

Answer 9

Small amounts of weakened or dead pathogens or just their antigens.

Question 10

How can vaccines be administered?

Answer 10

By mouth or by injection.

Question 11

What is activated when the body is exposed to antigens from a vaccine?

Answer 11

B cells are activated through clonal expansion.

Question 12

What happens during clonal expansion?

Answer 12

Activated B cells divide by mitosis to produce many identical cells.

Question 13

What do B cells differentiate into after clonal expansion?

Answer 13

Plasma cells and memory bee cells.

Question 14

What is the function of plasma cells?

Answer 14

They produce antibodies.

Question 15

What is the role of the memory bee cell?

Answer 15

They divide rapidly into plasma cells upon reinfection producing lots of antibodies quickly.

Question 16

What is herd immunity?

Answer 16

If enough of the population are vaccinated, the pathogen cannot spread easily amongst the population, this provides protection for those who are not vaccinated.

Question 17

What is the structure of HIV?

Answer 17

Core: genetic material and the enzyme reverse transcript which are needed for viral replication.
Capsid: outer protein coat
Envelope: extra outer layer made out of membrane taken from the host cell membrane.
Protein attachments: on the exterior of the envelope to enable the virus to attach to the host helper TTO

Question 18

How is HIV transported around the body?

Answer 18

In the blood

Question 19

What does HIV attached to on the health tea cell?

Answer 19

The CD4 protein.

Question 20

What happens after HIV attaches to the CD4 protein?

Answer 20

The HIV protein capsule fuses with the T cell membrane allowing RNA and the enzyme reverse transcriptase to enter.

Question 21

What enzyme does HIV use to copy its RNA into DNA?

Answer 21

Reverse transcriptase.

Question 22

Why is HIV called a retrovirus?

Answer 22

Because it converts RNA into DNA using reverse transcriptase.

Question 23

Where does the viral DNA go after it is made?

Answer 23

Into the helper T cell nucleus.

Question 24

What does the helper T cell do with the viral DNA?

Answer 24

Transcribes it into mRNA and makes viral proteins to assemble new HIV particles.

Question 25

What is AIDS?

Answer 25

It occurs when replicating HIV viruses interfere with the normal functioning of helper T cells and the immune system.

Question 26

What happens when helper T cells are destroyed by HIV?

Answer 26

The immune system can’t respond properly to pathogens.

Question 27

What is the result of weakened immunity due to HIV

Answer 27

Increased vulnerability to infections and cancer.

Question 28

What is direct monoclonal antibody therapy?

Answer 28

- using monoclonal antibodies with a designed binding site complementary in shape to the antigens on the outside of cancer cells - the antibodies are given to the cancer patient patient patient, and attached to the cells. This prevent chemicals binding to the cancer cells which enable uncontrolled cell division. - Therefore the monoclonal antibodies prevent the cancer cells growing

Question 29

What is a monoclonal antibody?

Answer 29

A monoclonal antibody is a single type of antibody that can be isolated and cloned antibodies are proteins which have binding sides complementary in shape to certain antigens.

Question 30

What is the Eliza test?

Answer 30

Uses an enzyme linked to immunosorbent assay - 1st antibody complementary to the antigen being tested for and has a colour attached - 2nd antibody complimentary in shape to the antigen is immobilised in the test - 3rd antibody is immobilised and is complimentary in shape to the antibody

Question 31

What are the ethical issues in creating monoclonal antibodies

Answer 31

Requires mice to produce the antibodies and tumour cells which leads to ethical debate as to whether this use of animals is justified to enable the better treatment of cancer and humans and detect disease.

Question 32

What is the process of the Eliza test?

Answer 32

1. Add patient test sample to the base of a beaker. 2. Add complimentary antibody to antigen you are testing the presence of 3. To remove unbound antibody. 4. Second antibody complimentary to the first antibody it has an enzyme attached to it 4. The substrate for the enzyme which is colourless is added this substrate produces coloured product in the presence of the enzyme 5. The presence of colour indicates the presence of the antigen in the test sample and the intensity of the colour indicates the quantity present.