Immune Respsonse

Question 1

What is a phagocyte?

Answer 1

a type of white blood cell that carries out an immune response known as phagocytosis.

Question 2

Summarise phagocytosis in a phrase:

Answer 2

Engulfment of pathogens

Question 3

Where are phagocytes found ?

Answer 3

In blood and in the tissues

Question 4

Which cells are the first to respond if an immune response is triggered?

Answer 4

Phagocytes

Question 5

How does a phagocyte work?

Answer 5

????

Question 6

How are T cells activated?

Answer 6

T cells are activated when the receptor proteins on their surface bind to complimentary antigens presented on phagocytes.

Question 7

Name two types of T cell

Answer 7

T helper cell
T cytotoxic cell

Question 8

T cells scan also be referred to as?

Answer 8

T lymphocytes

Question 9

What do T helper cells do in the immune response?

Answer 9

T helper cells do not attack the foreign or abnormal cels himself instead they release chemical signals called cytokines . These chemical signals stimulate phagocytes and T cytotoxic cells into killing the abnormal or foreign cells. T helper cells also stimulate B cells.

Question 10

If a T helper cell binds one of the receptor proteins on its surface to a complimentary antigen then what happens?

Answer 10

The T cell begins to replicate itself by mitosis to form many identical cells which carry the complimentary protein that binds to the invading antigen. The process is called clonal selection.

Question 11

What do T cytotoxic cells do?

Answer 11

attack antigens on cell membrane of foreign pathogens; release cytotoxic substances that destroy pathogen

Question 12

How are B cells stimulated ?

Answer 12

B cells can be stimulated by T helper cells as T helper cells release chemical signals to stimulate them. The binding of an antigen with a B cell receptor can also stimulate it into action.

Question 13

What is the surface of B cells covered in?

Answer 13

Antibodies

Question 14

What is formed when an antigen binds to an antibody?

Answer 14

an antigen-antibody complex

Question 15

Do all B cells carry the same antibodies?

Answer 15

No each B cell has a different shaped antibody on its membrane so different ones bind to differently shaped antigens.

Question 16

What happens when a B cell is activated?

Answer 16

When a B cell is activated it begins to divide into plasma cells , only the B cell which has complimentary antibodies to the antigens present begins to divide this is called clonal selection.

Question 17

What do plasma cells do?

Answer 17

secrete antibodies (monoclonal)

Question 18

What do the antibodies secreted by plasma cells do?

Answer 18

They bind to the antigens on the surface of the pathogen to form lots of antigen-antibody complexes

Question 19

How many binding sites does a single antibody have?

Answer 19

two binding sites, so can bind to two pathogens at the same time

Question 20

What process can occur due to the presence of two binding sites on a single antibody?

Answer 20

pathogens become clumped together — this is called agglutination. Phagocytes then bind to the antibodies and phagocytose many pathogens at once. This process leads to the destruction of pathogens carrying this antigen in the body.

Question 21

What are antibodies and thus what are they made from?

Answer 21

Antibodies are proteins — they’re made
up of chains of amino acids.

Question 22

What does the specificity of an antibody depend on?

Answer 22

The specificity of an antibody depends on its variable regions, which form the antigen binding sites. Each antibody has a variable region with a unique tertiary structure (due to different amino acid sequences) that’s complementary to one specific antigen

Question 23

what is the part of the antibody that is generic in all antibodies referred to as?

Answer 23

constant regions

Question 24

How are antibodies held together?

Answer 24

disulfide bonds

Question 25

Name the two types of immune response?

Answer 25

Cellular and humoral

Question 26

What is the cellular response?

Answer 26

the t-cells and other immune system cells that they interact with e.g phagocytes form the cellular response

Question 27

What is the humoral response?

Answer 27

B-cells, clonal selection and the production of monoclonal antibodies

Question 28

What is the primary response?

Answer 28

the immune response that results from the first exposure to an antigen

Question 29

Why is the primary response slow?

Answer 29

there arent many B cells that can make the antibody needed to bind to the antigen

Question 30

What do both T and B cells produce after being exposed to a antigen ?

Answer 30

Memory

Question 31

In the secondary immune response , the immune system produces a quicker stronger immune response , why is this?

Answer 31

Clonal selection happens faster. Memory B-cells are activated and divide into plasma cells that produce the right antibody to the antigen. Memory T-cells are activated and divide into the correct type of T-cells to kill the cell carrying the antigen. The secondary response often gets rid of the pathogen before you begin to show any symptoms