2. The Immune Response Flashcards Preview

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Flashcards in 2. The Immune Response Deck (12)
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1
Q

Name the 4 stages of immune response?

A
  1. Phagocytosis.
  2. T-cells.
  3. B-cells.
  4. Antibody Production.
2
Q

What is a phagocyte?

A

Its a type of white blood cells that carries out phagocytosis.
Found in the blood and tissue and are the first cells to respond to an immune system trigger inside the body.

3
Q

Describe the stages of phagocytosis.

A

Phagocyte recognises foreign antigen on pathogen.
Cytoplasm of phagocyte moves round pathogen- engulfing it.
Pathogen now contained in phagocytic vacuole in the cytoplasm of the phagocyte.
Lysosome fuses with phagocytic vacuole.
Lysozymes break down the pathogen.
Phagocyte then presents the pathogen’s antigens - sticks its the antigens on its surface to activate other immune system cells.
Phagocyte acts as an antigen-presenting cell.

4
Q

What is a T-cell?

A

Another type of white blood cell.
It has receptor proteins on its surface that bind to complementary antigens presented to it by phagocytes.
This activates the T-cells.

5
Q

Give an example of T-cell?

A

Helper T-cells release chemical signals that activate and stimulate phagocytes and cytotoxic T-cells, which kill abnormal and foreign cells.
TH cells activate B-cells which secrete antibodies.

6
Q

What are B-cells?

A

Type of white blood cells.
Covered with antibodies - proteins that bind to antigens to form an antigen-antibody complex.
Each one has different shaped antibody on its membrane, so different ones bind to different shapes antigens.

7
Q

Describe the process of clonal selection?

A

When the antibody on the surface of the B-cell meets a complementary antigen - it binds to it.
This, together with substances released from helper T-cells, activates the B-cells.
Activated B-cell divides into plasma cells?

8
Q

What does an activated B-cell do?

A

Divided into plasma cells.

9
Q

How are antibodies produced?

A

Plasma cells are identical to B-cells secrete loads of antibodies specific to the antigen.
These are called monoclonal antibodies.
They bind to the antigen on surface of pathogen to form loads of antigen-antibody complexes.

10
Q

How does an antibody destroy pathogens?

A

Antibody has 2 binding sites, so it can bind to 2 pathogens at same time.
Meaning pathogens become clumped together - this is called agglutination.
Phagocytes bind to antibodies and phagocytose many pathogens at once.
This leads to destruction of pathogens.

11
Q

Describe the structure of antibodies.

A

Proteins made up of chains of amino acids.
Secificty of antibody depends on its variable regions, which for antibody binding site.
Each antibody has a variable region with a unique tertiary structure thats complementary to one specific antigen.

12
Q

What do antibodies have?

A

VARIABLE REGION - forms binding site and has a tertiary structure.
They have the same constant regions.