Immunity

Question 1

What is a pathogen?

Answer 1

An organism which enters the body to feed and reproduce.

They may damage the body or poison it by excreting toxins.

Question 2

What types of microorganism can act as pathogens?

Answer 2

Viruses
Bacteria
Fungi
Protoctists

Question 3

What parts of the body act as physical barriers against pathogens preventing them entering the body?

Answer 3

Skin and membranes

Question 4

Which part of the blood takes over defence of the body if pathogens enter the body?

Answer 4

White blood cells

Question 5

There are two types of white blood cell. They are …

Answer 5

Phagocytes

Lymphocytes

Question 6

Name 2 parts of a phagocyte white blood cell.

Answer 6

Lobed nucleus

Lysozyme

Question 7

Describe how a phagocyte kills a pathogen.

Clue: it engulfs and breaks down pathogen

Answer 7

Phagocyte recognises pathogen
Phagocyte engulfs pathogen   (Phagocytosis)
Lysozyme move towards pathogen
Enzymes in lysozyme breaks down pathogen
Useful material absorbed by phagocyte 
Waste products removed

Question 8

Lymphocytes produce special Y shaped proteins called ….

Answer 8

Antibodies

Question 9

Antibodies from the lymphocytes attach to parts of the pathogen called…

Answer 9

Antigens

Question 10

Lymphocytes allow organisms to build up ………. towards a disease.

Answer 10

Immunity

Question 11

Describes how a lymphocyte white blood cell works.

Answer 11

Lymphocytes detects pathogen
Lymphocytes release different antibodies
Correct antibody connects to antigen of pathogen
Lymphocytes release large number of correct antibody
Pathogens either clump together and die or antibodies trigger phagocytes

Question 12

Antibodies specialised to combat toxins are called….

Answer 12

Antitoxins

Question 13

What are memory cells?

Answer 13

Cells produced by lymphocytes which can produce the correct antibody very quickly

Question 14

How long can memory cells remain in out circulatory system?

Answer 14

For a lifetime

Question 15

How do memory cells work?

Answer 15

Memory cells recognise a pathogen seen before and produce the correct antibody much quicker than the first time.

Question 16

What is immunity?

Answer 16

When memory cells have seen a pathogen before and can produce correct antibodies much quicker the next time.

Question 17

How does a vaccine work?

Answer 17

Body given a dose of a pathogen (injection)
The does is either dead pathogen or parts of the pathogen cell surface so it doesn’t give you the disease
Lymphocytes generate antibodies and memory cells.
Memory cells give us immunity