Disease

Question 1

Disease

Answer 1

A condition that impairs the normal functioning of a organism

Question 2

Communicable disease

Answer 2

A disease that’s spread between organisms

Question 3

Direct transmission

Answer 3

When a disease is transmitted directly from one organism to another. eg droplet infection coughing and touching

Question 4

Indirect transmission

Answer 4

When a disease is transmitted from one organism to another via and intermediate such as air,water or food.

Question 5

Barrier to infection: Skin

Answer 5

Physical barrier blocks pathogens from diectly entering the body also chemical as it releases chemicals that lower PH

Question 6

Mucous membranes

Answer 6

Protect body openings. Substance that traps pathogens contains microbacterial enzymes.

Question 7

Blood clotting

Answer 7

mesh of protein fibres. Blood clots plugs wounds to prevent pathogens from entering .

Question 8

Phagocytosis

Answer 8

This is the engulfment of pathogens. Phagocytes are found in the blood and in tissues.

Question 9

How does phagocytosis happen?

Answer 9

Phagocyte recognises the antigens on a pathogen. The cytoplasm of the phagocyte moves around the phagocyte engulfing it, the pathogen now contained in a phagosome. A lysosome fuses with the phagosome and enzymes break down pathogens.

Question 10

Neutrophils

Answer 10

They are a type of phagocyte; first white blood cells to respond to the pathogen act as messenger molecules.

Question 11

T lymphocytes

Answer 11

Surface covered with receptors; bind to antigens presented by APC’S each T lymphocyte has a different receptor on its surface and when it meets a complementary antigen, it binds and activates it and starts clonal selection

Question 12

T helper cells

Answer 12

These release substances to activate B lymphocytes which divide into plasma cells

Question 13

B lymphocytes

Answer 13

Covered in antibodies and they bind to antigens to form an antigen-antibody complex that binds to complementary shaped antigen activating the lymphocyte then it divides by mitosis into plasma and memory cells.

Question 13

Plasma cells

Answer 13

These are clones of B lymphocytes and secrete loads of the antibody specific to the antigen into the blood

Question 14

Antibodies

Answer 14

Glycoproteins- made up of four pelypeptide chains two heavy and two light each chain has a variable region made of disulfide bridges- hinge region allows flexibility when antibody binds to antigen.

Question 15

Aggulating Pathogens

Answer 15

Antibody 2 binding sites- bind to 2 pathogens at once and they become clumped together phagacytes then bind to antibodies and phagocytose alot of them at once