Immunity

Question 1

What is involved in the primary response?

Answer 1

Naive B cells
4-7 day lag
10-14 day response
Slower
More general antibodies.

Question 2

What is involved in the secondary response?

Answer 2

Memory B cells
1-3 day lag
5-7 day response
Higher concentration of antibodies.
More specific antibodies

Question 3

What do antigens allow the immune system to identify?

Answer 3

Pathogens
Toxins
Abnormal body cells
Cells from other organisms of the same species (organs)

Question 4

What are the stages of the immune response?

Answer 4

Phagocytosis
T cells
B cells

Question 5

Example of natural active immunity

Answer 5

Infection

Question 6

Example of an artificial active immunity

Answer 6

Vaccines

Question 7

What is active immunity?

Answer 7

Direct contact with antigens.
Own immune system produces antibodies.
Long process

Question 8

What does active immunity result in?

Answer 8

Plasma and memory cells
Long term immunity

Question 9

Example of natural passive immunity

Answer 9

Mothers milk
Placenta

Question 10

Example of artificial passive immunity

Answer 10

Cultured antibodies

Question 11

What is passive immunity?

Answer 11

No direct contact with antigens.
Antibodies are introduced from an outside source.

Question 12

What does passive immunity result in?

Answer 12

Not long lasting.
Immediate effect.
Does not create memory cells.

Question 13

What is a vaccine?

Answer 13

The introduction of antigens into the body in order to stimulate an immune response leading to the production of memory cells which provide long term immunity.

Question 14

What is herd immunity?

Answer 14

When a sufficiently large population is vaccinated so it is difficult for the pathogen to spread. Protects those who cannot be vaccinated

Question 15

What is HIV?

Answer 15

A retro virus.
Therefore it has enzymes which can make DNA from RNA

Question 16

What does reverse transcriptase do?

Answer 16

Catalyses reverse transcription, which forms viral DNA from viral RNA.

Question 17

What does integrase do?

Answer 17

Catalyses integration of viral DNA into the genome of the host cell.

Question 18

What does protease do?

Answer 18

Catalyses the breakup of large polyproteins. Critical for the assembly of new viral particles called virions.

Question 19

What type of response are B cells?

Answer 19

Humoral

Question 20

What do B cells do?

Answer 20

Produce antibodies that help destroy pathogens by causing agglutination.
Become antigens presenting cells and rapidly divide.

Question 21

What do B cells differentiate into?

Answer 21

Memory B cells
Plasma cells

Question 22

What do memory B cells do?

Answer 22

Rapidly produce specific antibodies in case of reinfection. Provide long term immunity.

Question 23

What do plasma cells do?

Answer 23

Produce specific antibodies that initiate the response of the phagocyte.

Question 24

What type of response are T cells?

Answer 24

Cell mediated

Question 25

What do T cells do?

Answer 25

Receptors on T cells bind to antigens on the antigens presenting cells. Cause rapid division of T cells. Stimulate phagocytosis

Question 26

What do T cells differentiate into?

Answer 26

Memory T cells Helper T cells Cytotoxic T cells

Question 27

What does memory T cells do?

Answer 27

Enable a rapid response to reinfection.

Question 28

What do Helper T cells do?

Answer 28

Stimulate B cells to divide and secrete antibodies

Question 29

What do Cytotoxic T cells do?

Answer 29

Kill abnormal cells and infected body cells. Release a protein called perforin, which creates pores in the cell membrane. Causes cell death

Question 30

What are the stages of phagocytosis?

Answer 30

Foreign antigens are detected. Phagocyte engulfs bacterium in a sealed vacuole. Lysosome fuses with bacterium. Releases enzymes to break it down. Phagocyte presents the pathogens antigens as an antigens presenting cells. Triggers other immune responses.

Question 31

How does HIV become AIDS?

Answer 31

Immediately after infection = suffer mild flu like symptoms. Period of latency. Viral DNA replicates after several months or years. Virus particles become active and gradually destroy T Helper cells. B cells are not stimulated. No more antibodies. Begin to suffer from opportunistic pathogens.

Question 32

Structure of antibodies?

Answer 32

2 binding sites. 2 chains. Hinge region

Question 33

Where do antibodies bind to the antigens to from a complex?

Answer 33

The variable region.

Question 34

How does HIV replicate?

Answer 34

Gp120 HIV protein binds to CD4 receptors on T Helper cell. Enters host cell. Capsid injected into cytoplasm. Viral RNA is released. Capsid dissolves. Reverse transcription. Integration of viral DNA. Protease breaks up polyproteins. Budding. Virions released out of cell by exocytosis.

Question 35

How are monoclonal antibodies formed?

Answer 35

An foreign pathogens antigen is injected into a mouse to trigger an immune system. This stimulates antibodies from the B cells. These cells are fused with a tumour to form hybridoma cells. Cloned to produce large quantities of identical antibodies.