Immunolgy

Question 1

Antigen definition

Answer 1

A molecule usually a protein on the surface of a molecule that stimulates an immune response and results in the production of specific antibodies complementary to specifically shaped antigens

Question 2

What four types of cells can the immune system identify?

Answer 2

Toxins
Pathogens
Foreign cells
Abnormal body cells

Question 3

Name three 3 stages of the immune response

Answer 3

1. Phagocytosis
2. T cells
3. Humorist response

Question 4

Describe phagocytosis

Answer 4

The phagocyte engulfs the pathogen by endocytosis and enters the cytoplasm forming a vesicle called phagosomes. Lysosomes contain hydrolytic enzymes and digest phagocyte into waste material and leaves by exocytosis The antigen transported to the surface of the phagosome where it presents itself as an ATC

Question 5

T cell activation

Answer 5

T cell with specifically complementary receptor protein binds to the antigen on antigen presenting cell. Tea saw is now activated and rapidly differentiate by clone selection by mitosis.

Question 6

Three types of t cells differentiate into?

Answer 6

1. More t helper cells which bind to APC and release cytokines which 1. Stimulates b cells to differentiate 2. Form t memory cells 3. Stimulates t cytokines cells which locate and destroy body cells and release perforin which destroys membrane of phagocyte by making holes.

Question 7

Humoral response

Answer 7

1. A specific T- helper cell binds to APC and activates a production of specifically complex B cells
2. T- helper cells release cytokines which sign B cells to differentiate by mitosis
3. B cells can then differentiate into 2 types of cells:
4. Plasma cells= secrete and produce a vast quantity of specific antibodies into blood plasma
5. Memory cells= circulate in the blood and respond to same future pathogen quicker.

Question 8

Antibodies definition

Answer 8

Specifically complementary protein made in response to antigen. A specific antibody is produced by a specific plasma cell

Question 9

Structure an an antibody

Answer 9

Made up from 4 polypeptide chains- 2 light chain 2 heavy chain 2 beats 2 alpha glucose
Forms a quaternary structure
Is y shaped
Has a variable regions which have different tertiary structure therefore is different to every molecule
Has variable constant which remains the same
Has2 binding sites fir antigens

Question 10

How do antibodies assist destruction of pathogens

Answer 10

Each antibody is specific to each antigen so can only form antigen antibody complexes with one type of antigen by
1. Agglutination = which clumps them together decreasing concentration of pathogens so quicker destruction
2. Opsonisation = marking pathogens so phagocytes can recognise and destroy more efficiently
3, lysis = bind to antigen and destroy its membrane

Question 11

Memory cells

Answer 11

They are activated by T helper cells cytokines and divide rapidly by mitosis which differentiate into many plasma cells and more memory b cells

Question 12

Secondary response

Answer 12

The activation of memory cells to produce antibodies which is both rapid and extensive

Question 13

Antigenic variability

Answer 13

Gene mutation and pathogen may lead to change in tertiary structure of antigens , specific B cells meaning memory cells antibodies will no longer complimentary to pathogen so no antigen - antibody complex will form

Question 14

Passive vs active

Answer 14

Passive = no exposure to antigen, mo memory cells produced, short term , fast acting antibodies are given
Active = exposure to antigen, memory cells are produced. Long term , takes time to develop and antibodies are produced

Question 15

Ethics to vaccine

Answer 15

Human testing
Animal testing
Dosage
Cost
Choice
Side effects

Question 16

Monoclonal antibodies

Answer 16

Antibodies formed from one clone of plasma b cells

Question 17

Use of monoclonal antibodies

Answer 17

Research
Killling specific cells
Targeting drugs
Diagnosis
Immuno assays

Question 18

Elisa test

Answer 18

Specific Antigen bound to bottom of well, add patents blood sample. Specific antibodies in blood attach to antigens. Wash to get rid of excess. Add 2nd antibody attached with enzyme which enzyme linked antibody attached to specific antibody. Wash. Add substrate which binds to enzyme and forms coloured product . More coloured product = longer time infected

Question 19

Herd immunity

Answer 19

If enough individuals in the population are vaccinated then little chance of diseases spreading and even those that are not vaccinated will be protected

Question 20

HIV structure

Answer 20

Lipid envelope
Capsule
Reverse enzymes
RNA ( single stranded )
Attachment proteins

Question 21

Describe HIV replication

Answer 21

1. Attachment protein bind to receptor proteins on T helper cell
2. Capsid fuses will cell membrane and relaeses RNA and reverse transcriptase
3. Reverse transcriptase converts RNA back into cDNA using host nucleotides then dsDNA by DNA polymerase.
   4,. Viral DNA moves into nucleus of T cell and inserted into host cell genome
   Transcription and translation forms HIV proteins .
   Particles break way with a section of host cell surface membrane to form lipid envelope with receptor proteins embedded.

Question 22

AIDs

Answer 22

More HIV
More destruction of TH cells
Less activation of b cells
Less able to destroy pathogens as no antibodies formed from plasma cells