Immunity

Question 1

What is cellular response?

Answer 1

Activation of phagocytes, helper T and Killer T cells

Question 2

What is humoral response?

Answer 2

Activation of B cells and the production of antibodies

Question 3

What is active immunity?

Answer 3

Immunity which results from the production of antibodies by the immune system in response to an antigen

Question 4

What is passive immunity?

Answer 4

Short term immunity which results from the introduction of antibodies from another person or animal

Question 5

What is phagocytosis?

Answer 5

The destruction of ingested pathogens by lyzosomes

Question 6

What type of immune cell destroys infected body cells?

Answer 6

T killer

Question 7

What is a phagocyte?

Answer 7

A type of white blood cell that carries out a process called phagocytosis

Question 8

What is the role of macrophage cells?

Answer 8

Engulf and digest pathogens

Question 9

What is a phagocytic vacuole?

Answer 9

It is formed which has the pathogen engulfed in it

Question 10

What is a lysosome?

Answer 10

A lysosome is a membrane-bound cell organelle that contains digestive enzymes

It fuses itself with the phagocytic vacuole which contains lysosomal enzymes that breaks down the pathogen

Question 11

How do macrophages activate other immune cells? (T cells)

Answer 11

Phagocyte presents the antigens to them

Question 12

What two roles do T cells have?

Answer 12

• It releases substances to activate B-cells

- Attach to antigens on a pathogen and kill the cell

Question 13

What is a B cell?

Answer 13

A type of immune cell that makes plasma cells that secrete lots of anitbodies and memory cells

Question 14

What is an antigen-antibody complex?

Answer 14

B-cells are covered with antibodies that bind with antigens making an antigen-antibody complex

Question 15

What is the term for a range of chemicals which are released by cells to signal instructions to other cells?

Answer 15

Cytokines

Question 16

Which type of immune cell can respond more quickly to a second infection by a particular pathogen thereby giving immunity?

Answer 16

Memory

Question 17

What are three functions of an antibody?

Answer 17

• Coating the pathogen to make it easier for the phagocyte to engulf it
• Coating the pathogen to prevent it from entering host cells
• Binding to and neutralizing toxins produced by the pathogens

Question 18

What is an antibody?

Answer 18

A Y-shaped protein molecule made of 4 polypeptide chains held together by disulfide bridges

Question 19

What is an antigen?

Answer 19

Substance that causes an immune response/production of antibodies

Question 20

What is an antibiotic?

Answer 20

A microorganism used to kill bacterial cells e.g. penicillin

Question 21

What is a monoclonal antibody?

Answer 21

Antibody produced by a single clone of cells with identical antibody molecules. Merging tumour cells with specific antibody to replicate wanted antibody

Question 22

What are the uses of monoclonal antibodies?

Answer 22

Pregnancy test, AIDS test - cancer treatment to destroy cancer cells - transplant surgery to knock out specific killer T cells.

Question 23

What are some ethical considerations of the use of monoclonal antibodies?

Answer 23

Involves the use of mice to produce antibodies and cancer tumour cells. Testing for the safety of new drugs presents certain dangers. On the other hand, has been used to save many lives against cancer and diabetes.

Question 24

What is the ELISA test?

Answer 24

Enzyme linked immunosorbent assay. It uses antibodies to not only detect the presence of a protein in a sample but also the quantity.

Question 25

How does the ELISA test work?

Answer 25

• Apply sample to a slide to which all the antigens in the sample will attach
• Wash the surface several times to remove unattached antigens and add antibody that is specific to the antigen
• Wash surface to remove excess antibody. Only antibodies attached to antigen remain in well.
• Add colourless substrate of the enzyme. Enzyme acts on the substrate to change it into a coloured product.
• Amount of antigen present is relative to the intensity of colour that develops

Question 26

What is agglutination?

Answer 26

The process by which many antibodies bind to and group together several pathogens.

Question 27

What is HIV?

Answer 27

Human immunodeficiency Virus

Question 28

How does the HIV virus evolve?

Answer 28

Invades T helper cells by hijacking their proteins synthesis machinery

Question 29

A type of immune cell attacked by HIV?

Answer 29

Helper T

Question 30

How does HIV cause symptoms of AIDS?

Answer 30

HIV destroys T cells, which are crucial to maintaining the function of the immune system. As HIV attacks these cells, the person infected with the virus is less equipped to fight off infection and disease

Question 31

Why are antibiotics ineffective against viruses?

Answer 31

Antibiotics work by preventing bacteria from making normal cell walls. They prevent the development of peptide cross linkage which weakened cells walls, making them unable to withstand pressure. Water enters naturally by osmosis, the cell bursts and bacterium dies.

Question 32

How does infection with HIV result in the death of T cell?

Answer 32

HIV recognises helper T cells receptor using its glycoproteins. Once the virus has utilised the cell it can initiate cellular destruction.

Question 33

What is a vaccine?

Answer 33

A dead or weakened version of a virus