Topic 2-The immune response

Question 1

What are the 4 stages of the immune response?

Answer 1

-Phagocytosis
-T cells
-B cells
-Antibody production

Question 2

What is a phagocyte?

Answer 2

-A type of white blood cell that carries out phagocytosis

Question 3

Where are phagocytes found?

Answer 3

-Found in the blood and tissues

Question 4

True/ false: Phagocytes are the first cells to respond to an immune system trigger inside the body

Answer 4

True

Question 5

What is the first step of phagocytosis?

Answer 5

-A phagocyte recognises the foreign antigens on pathogen

Question 6

What is the 2nd step of phagocytosis?

Answer 6

-The cytoplasm of the phagocyte moves around the pathogen, engulfing it

Question 7

What is the 3rd step of phagocytosis?

Answer 7

-The pathogen is now contained in a phagocytic vacuole in the cytoplasm of the phagocyte

Question 8

What is the 4th step of phagocytosis?

Answer 8

-A lysosome fuses with the phagocytic vacuole
-The lysosomes break down the pathogen

Question 9

What is the 5th step of phagocytosis?

Answer 9

-The phagocyte then presents the pathogen’s antigens
-It sticks the antigens on its surface to activate other immune system cells
-The phagocyte is acting as an antigen-presenting cell

Question 10

What does the T cell stand for?

Answer 10

-T-lymphocyte

Question 11

What is a T cell?

Answer 11

-A type of white blood cell

Question 12

What activates the T cell?

Answer 12

-It has receptor proteins which bind to complementary antigens presented by phagocytes

Question 13

How do helper T cells respond?

Answer 13

-Release chemical signals which activate and stimulate phagocytes
-Activate B cells

Question 14

How do cytotoxic T cells respond?

Answer 14

-Kill abnormal and foreign cells

Question 15

What are B cells?

Answer 15

-B lymphocytes
-A type of white blood cell

Question 16

What do B cells form and how?

Answer 16

-Antigen-antibody complex
-They are covered in antibodies

Question 17

Define antibodies

Answer 17

-Proteins that bind to antigens to form an antigen-antibody complex

Question 18

What is different about each B cell?

Answer 18

-They have a differently shaped antibody on their membrane

Question 19

Explain the process of clonal selection

Answer 19

-Antibody on the surface of B cell meets complementary antigens they bind together
-With substances released from helper T cells it activates the B cell

Question 20

What do activated B cells divide into?

Answer 20

-Plasma cells

Question 21

Why do antibodies bind to antigens?

Answer 21

They have a complementary shape

Question 22

What do B cells and T helper cells have in common?

Answer 22

-Both have receptor proteins
-On B cells they bind to the signalling molecules released by the T helper cells

Question 23

What is the function of plasma cells?

Answer 23

-They secrete loads of antibodies specific to the antigens
(monoclonal antibodies)

Question 24

How many binding sites does an antibody have?

Answer 24

-2
-So they can bind two pathogens at a time

Question 25

What is agglutination?

Answer 25

When pathogens clump together

Question 26

What happens after agglutination? What does this lead to?

Answer 26

-Phagocytes then bind the antibodies and phagocytose many pathogens at a time
-The destruction of pathogen carrying the antigen in the body

Question 27

What does the specificity of an antibody depend on?

Answer 27

-Variable regions which form the antigen binding sites

Question 28

Why does each antibody have a variable region with a unique tertiary structure that is complementary to one specific antigen?

Answer 28

-Different amino acid sequences

Question 29

What is the same in all antibodies?

Answer 29

-The constant regions

Question 30

What are the 2 parts of the immune response?

Answer 30

-Humoral
-Cellular

Question 31

What makes up the cellular response?

Answer 31

-The T cells
-Other immune system cells they interact with (phagocytes)

Question 32

What makes up the humoral response?

Answer 32

-B cells
-Clonal selection
-Production of monoclonal antibodies

Question 33

What is the primary response?

Answer 33

When an antigen enters the body for the first time and activates the immune response

Question 34

Why is the primary response slow?

Answer 34

There aren’t many B cells that can make the antibody needed to bind to the antigen

Question 35

What will happen when the person is producing the antibodies?

Answer 35

They will show symptoms

Question 36

What happens after both the B and T cells are exposed to the antigen?

Answer 36

Memory cells are created

Question 37

What is the function of memory T cells?

Answer 37

-Remember the specific antigen and will recognise it the 2nd time around

Question 38

What is the function of memory B cells?

Answer 38

-Record the specific antibodies needed to bind to the antigen

Question 39

What is meant by immune?

Answer 39

-Their immune system can respond to the 2nd infection

Question 40

What is the secondary response?

Answer 40

-When the same pathogen enters the body again, the immune system will produce a quicker, stronger immune response

Question 41

What happens during the secondary response?

Answer 41

-Clonal selection happens more quickly
-Memory B cells activated- divide into plasma cells that produce the right antibody for antigen
-Memory T cells are activated and divide into the correct T cell to kill the cell carrying the antigen

Question 42

Are symptoms shown during the secondary response?

Answer 42

-No