The Immune system

Question 1

What is an antigen?

Answer 1

Antigens – proteins that generate an immune response.

Question 2

What do antibodies detect?

Answer 2

-Detects: pathogens, abnormal body cells (cancer), toxins and other cells from same species (organ rejection)

Question 3

what is a phagocyte and what is phagocytosis?

Answer 3

Phagocytosis – the process in which the pathogen is engulfed
Phagocyte – the white blood cell that carries out phagocytosis

Question 4

describe phagocytosis

Answer 4

• Cytoplasm of the phagocyte engulfs the pathogen
• A Lysosome joins phagocyte and digests the pathogen
• phagocyte shows antigen of pathogen to stimulate other cells

Question 5

what is a T-cell?

Answer 5

T – cells – type of white blood cell that recognises antigens of the pathogen

Question 6

What are the two types of T-cell?

Answer 6

• Helper T–cells – stimulates phagocytes; activates B-cells
• Cytotoxic T-cells – kills foreign cells

Question 7

What is a B-cell?

Answer 7

B-cells – type of white blood cells, forms antigen-antibody complexes

Question 8

what is an antibody

Answer 8

Antibody – complementary protein that binds to antigens

Question 9

what is the clonal section

Answer 9

• Clonal selection – process where B and T cells are produced

Question 10

what do B-cells divide into

Answer 10

• B-cells divide into plasma cells

Question 11

what is a plasma cell?

Answer 11

Plasma cells – makes antibodies for a specific antigen, clones of b cells

Question 12

what are plasma cells a clone of?

Answer 12

B-cells

Question 13

define monoclonal antibody

Answer 13

Monoclonal antibodies – antibodies that can clone themselves

Question 14

what do antibodies and antigens form

Answer 14

antibody-antigen complexes

Question 15

what makes different antibodies unique?

Answer 15

variable regions – complementary to the specific antigen

Question 16

how are variable regions different?

Answer 16

they have a different tertiary structure

Question 17

what do variable regions form

Answer 17

antigen binding sites

Question 18

What makes antibodies the same?

Answer 18

all antibodies have the same constant regions

Question 19

what is agglutination?

Answer 19

Agglutination – where pathogens are moved closer together

Question 20

how many binding sites are there in an antibody and how any antigens can bind?

Answer 20

Antibodies have two binding sites –> 2x antigens can bind at the same time

Question 21

what is the structure of an antibody

Answer 21

Structure: 4x variable regions, 4x disulfide bridges, 2x hinge proteins, the rest of the antibody is made from constant regions, they are coated in heavy chain

Question 22

how many variable regions are in an antibody

Answer 22

4 variable region

Question 23

how many disulphide bridges are in an antibody

Answer 23

4 sulfide bridges

Question 24

how many hinge proteins are in an antibody

Answer 24

2 hinge proteins

Question 25

what is the rest of the antibody made from

Answer 25

constant regions

Question 26

What are the two types of immune response?

Answer 26

cellular humoral

Question 27

What is the cellular immune response?

Answer 27

Cellular – immune system cells (T-cells and phagocytes) that directly interact with pathogens

Question 28

What is the humoral immune response?

Answer 28

Humoral – B-cells, clonal section and monoclonal antibodies

Question 29

what is the primary immune response?

Answer 29

Primary immune response – when the immune system is activated by a particular antigen for the first time

Question 30

how is the primary response characterised?

Answer 30

- Slower --> not many B-cells to bind to them - Body will make enough antibodies to overcome infection, symptoms are present in patient

Question 31

What is a memory cell?

Answer 31

Memory cells – produced by B-cells and T-cells, remain in the body

Question 32

what are the two types of memory cells produced in the primary response?

Answer 32

Memory T-cells Memory B-cells

Question 33

what are memory T cells?

Answer 33

Memory T-cells – remembers the antigen and will recognise it when it comes back

Question 34

what are memory B-cells?

Answer 34

Memory B-cells – remembers the antibodies needed to bind to the antigen

Question 35

define immune

Answer 35

Immune – where a person can respond quickly to a second infection

Question 36

what is the secondary immune response?

Answer 36

Secondary immune response – where the body responds quicker upon reinfection

Question 37

what are characteristics of the secondary immune response?

Answer 37

- Clonal selection is faster  Memory b-cells divide into plasma cells (produces the right antibody for the antigen), memory T-cells are activated and kill the cells - Secondary response gets rid of pathogens before symptoms appear

Question 38

what is a phagocytic vacuole

Answer 38

bubble in cytoplasm of the vacuole

Question 39

What are the 5 steps in the immune response?

Answer 39

1. phagocytosis 2. phagocytes activate the T-cells 3. T-cells activate the B-cells 4. B-cells divide into plasma cells 5. plasma cells make antibodies for a specific antigen

Question 40

why do plasma cells make antibodies for a specific antigen?

Answer 40

because they're B-cell clones

Question 41

What activates T-cells?

Answer 41

Phagocytes

Question 42

What activates B-cells?

Answer 42

T-cells

Question 43

what type of protein is on T- cells?

Answer 43

receptor protein

Question 44

What do receptor proteins (on the T-cells) do?

Answer 44

bind to complementary antigens (presented by phagocytes)

Question 45

what is a vaccine?

Answer 45

contain antigens that cause the body to produce memory cells against the pathogen, without causing disease

Question 46

what do vaccines not cause?

Answer 46

disease

Question 47

how can you tell if someone is immune?

Answer 47

no symptoms

Question 48

what is herd immunity?

Answer 48

when lots of people are vaccinated, it protects those who aren’t vaccinated

Question 49

how does herd immunity prevent those who don't have vaccine?

Answer 49

as there are fewer people to catch it from

Question 50

what is ring immunity?

Answer 50

where only the people around an infected person are immune

Question 51

what are oral vaccines?

Answer 51

vaccines taken orally

Question 52

what are the disadvantages of oral vaccines?

Answer 52

could be broken down by enzymes or molecules are too large to be absorbed into the bloodstream

Question 53

what is antigenic variation?

Answer 53

different antigens are formed due to mutations in genetic code of pathogen

Question 54

what is the alternative name for antigenic variation?

Answer 54

antigen variability

Question 55

what is a characteristic of antigen variation seen in patients?

Answer 55

- No memory cells for new antigen, primary response carried out again - This takes time and patient gets ill again, hard to develop vaccines against

Question 56

what is flu?

Answer 56

influenza vaccines change every year, antigens change, and new strains are formed

Question 57

what is Immunologically distinct?

Answer 57

memory cells from one strain will not recognise antigens from a different strain of the virus

Question 58

what is active immunity?

Answer 58

where the immune system makes its own antibodies when stimulated by an antigen, this takes time but gives long term protection

Question 59

what is natural active immunity?

Answer 59

when you become immune after catching the disease

Question 60

what is active artificial immunity?

Answer 60

where you become immune after vaccination (containing low dose)