Topic 4 As Whole CellRecingnition And Immune System

Question 1

What is an antigen?

Answer 1

An antigen is a foreign protein present on CELL-SURFACE MEMBRANE that stimulates an IMMUNE RESPONSE.

Question 2

What is Antigenetic Variability?

Answer 2

Pathogens(bacteria) and viruses MUTATE changing DNA or RNA sequence of antigen which changes the Tietary structure so can look different so
IMMUNE SYSTEM wont be able to detect newly mutates ANTIGENS so wont die.

Question 3

What is Phagocytosis?

Answer 3

Phagocytosis is the engulfment of pathogen by a phagocyte.

Question 4

How does is Pathogen attacked by Phagosome?

Answer 4

Pathogen is ENGULFED by phagocyte by ENDOCYTOSIS forming PHAGOSOME.

Question 5

How is pathogens destroyed by Phagocyte in phagocytosis?

Answer 5

Lysosomes fuse with Pathogens and PROTEOLYTIC ENZYMES such as lysozymes break down pathogen into soluble material for various process.

Question 6

What is formed from phagocytosis that is used in cell-mediated response?

Answer 6

In phagocytosis after pathogen is broken down etc.. Antigens on pathogens presented on Surface of Phagocyte so phagocyte become Antigen-Presenting cell for cell mediated response.

Question 7

What type of cell is a phagocyte?

Answer 7

A phagocyte is a type of white blood cell.

Question 8

What kind of cells are B-cells and T-cells?
What are they involved in?
Where are they matured?

Answer 8

B-cells and T-cells are lymphocytes(type of white blood cells)
B-cells mature in Bone marrow and involved in Hummoral Response.
T-cells mature in Thymus Gland involved in cell-mediated response.

Question 9

In cell-mediated response how are clones of T-cells produced and what do they differentiate into?

Answer 9

T-cells RECEPTORS bind to Antigen on Antigen-Presenting Cells which stimulates RAPID DIFFERENTIATION of T-cells producing Clones of T-cells which differentiate.

Question 10

In cell-mediated responded how and which T-cells are produced?

Answer 10

Rapid differentiation of T-Cells produces Clones of T-Cells.
Rapid differentiation is caused by T-cells receptors bind to Antigen-Presenting cells which stimulate rapid differentiation.

Question 11

Which type of T-cells are produced in cell-Mediated response and what are the uses of the T-Cells?

Answer 11

1.Helper T-Cells-Involved in Hummoral Response.
2.Clones of T-Cells-Stimulate Phagocytosis
3.Cytoxic T-cells-produces a protein called Perforin which makes holes in cell membrane of Pathogen this allows substances to enter pathogen causing cell death.

Question 12

In cell-mediated response how are pathogen killed?

Answer 12

Perforin makes holes in cell-membrane this allow substances to enter pathogen causing cell death.

Question 13

What are Antibodies?

Answer 13

Antibodies are Proteins that have a Binding site Complementary to Antigens and destroy pathogens.

Question 14

What is the Structure of Antibodies?

Answer 14

Four Polypeptide chain: 2 light+ 2 heavy
Disulphide Bridges Link the Polypeptide chains
Chain split into constant and Variable region
Constant region is present in all antibodies
Variable region makes Antibodies specific to particular Antigen so can be killed.

Question 15

How are clones of ….. produced in Hummoral Response?

Answer 15

Helper T-Cells stimulate B-Cells to rapidly divide by MITOSIS to form clones of plasma cells - clonal selection.

Question 16

What are the purpose of plasma cells?

Answer 16

Plasma cells produce Antibodies that have a specific shape to Antigens and destroy pathogens.

Question 17

What is the advantage of Hummoral response?

Answer 17

The advantage is Aggultination and this is when antibodies bind to antigen forming AntibodyAntigen complex so all stick together
The advantage of this pathogen easily digested by PHAGOCYTOSIS as larger clumps easily detected by Phagocyte.

Question 18

What is Significant of secondary response?
Why is secondary response present?

Answer 18

2nd response is the 2nd response with the pathogen.
2nd response is present because once antibodies destroy pathogen Memory B-cells formed.

Question 19

What are Memory B-Cells?

Answer 19

Memory B-Cells remember how to produce Antibodies that kill particular pathogen.

Question 20

What are Vaccination and what is the main purpose of vaccination?

Answer 20

In vaccination you have a vaccine you have a dead/inactive pathogen which indicates primary response leading to formation of Memory B-Cells

Main purposive is Herd Immunity

Question 21

What are the two type of immunity?
Give examples

Answer 21

Active Immunity is result from production of Antibody by immune system response to presence of antigen
Passive Immunity result from ‘Introduction’ of antibodies from another person/animal.
Passive immunity-Artificial-Anti-venom
Natural Immunity -Breast Feeding

Question 22

How are Monoclonal Antibodies acquired ?
What is the function of Monoclonal Antibodies?

Answer 22

Monoclonal Antibody us the type of antibody isolated from single clone of B- cells
Monoclonal Antibodies is used for drug targeting to target specific drugs.

Question 23

What is the purpose of Elisa Test?
What is the first 3step?

Answer 23

The function of the Elisa test is to detect antigens if person has particular disease.

1.Antigen of interest IMMOBILISED through patients blood sample.

2.Monoclonal Antibodies added and bind to appropriate antigen.

3.Apparatus washed to remove unbound antigen

Question 24

How is colour change causes in Elisa Test?
[Last three steps in Elisa Test]

Answer 24

More Monoclonal antibodies added which linked to colour changing enzymes and bind to antigen.

Apparatus washed again to remove unbound antigen.

Complementary Substate to the enzyme is added which triggers colour upon binding which shows presence of antigen.

Question 25

How does HIV RNA transcriptase enter host cell and what is purpose of RNA transcriptase in HIV?

Answer 25

HIV attaches to CD4 receptors on Helper-T cells
RNA and Enzymes enter host cell.
Reverse Transcriptase converts VIRAL RNA to cDNA

Question 26

In HIV replication what does cDNA do?

Answer 26

cDNA moves into (Helper-T-Cell) nucleus where its TRANSCRIBED and TRANSLATED using host machinery to produce Virus proteins which make new proteins.

Question 27

How does HIV kill Helper T cells?

Answer 27

New viruses produced break of Helper T cell membranes causing Helper T-Cells to die a d HIV go on to replicate even more cells.

Question 28

How does HIV cause aids?
How do HIV drugs work?

Answer 28

Helper T-Cells are used in Hummoral response so decreased B-Cells Stimulation so decreased immunity so less Hummoral response

HIV drugs work by targeting Reverse Transcriptase so no genetic material entering nucleus.