3.2.4 Cell Recognition And The Immune System

Question 1

Definition of pathogen , how it works

Answer 1

Organism that cause disease
E.g. Bacteria, viruses and fungi.

Release toxin
Kill cell / tissue

Question 2

Where is toxin produce?

Answer 2

Bacteria

Question 3

What is physical and chemical defence?

Answer 3

Physical defence (non special)
Skin, saliva, membrane lining, Cilia
Chemical defence
Stomach acid, urine, tear, mucus ,sweat

Question 4

Two types of leukocytes

Answer 4

Phagocytes (non-specific)
Lymphocyte (specific)
T cell - cell mediated : only antigen on surface of the cell, produce in bone marrow mature in thymus gland
B cell - humoral : antigen in body fluid, produce and mature in bone marrow

Question 5

What are those surface molecule for identifying they are nonself cell?

Answer 5

Pathogens
Cell from other organisms or same species (organ transplant)
Abnormal body cell (tumour)
Toxins

Question 6

Why and how antigen variability created, fix

Answer 6

DNA mutate frequently shape of antigen will change
Previous immunity is no longer effective on memory cells, have memory of old antigen shape
Influenza virus mutates very quickly new f
So new flu vaccine create each year

Question 7

Process of phagocytosis

Answer 7

1. Chemicals are released by the pathogen.
2. The phagocytes are attracted to this chemical(foreign substance) and move toward to pathogen
3. The phagocyte engulf the pathogen forming vesicles (phagosome)by endocytosis.
4. Lysosome found in the phagocyte , Move to vesicles and fused.
5. Lysozyme.(hydrolytic, enzyme) in lysosome digest, the pathogen
6. They display the important antigen on the self-surface membrane.

Question 8

Composition of blood

Answer 8

Plasma
White blood cell (leukocyte)
Platelets (thrombocytes)
Red blood cell (Erythrocytes)

Question 9

What is antibody?

Answer 9

Antibody or protein produced by the plasmid (B lymphocytes) which has a big cytoplasm and rough ER

Question 10

The structure of antibody

Answer 10

Y shape
4 Disulphide bond
Specific tertiary structure
Variable side only complimentary to one specific antigen due to specific amino acid sequence
Only bind to form an antigen antibody complex with specific antigen
Quaternary structure , we got two or more polypeptide chain

Question 11

When an antigen bind to an antibody, what is formed

Answer 11

Antigen antibody complexed

Question 12

What is clump to create a network of antigen antibody complex so that phagocytosis occur?

Answer 12

Agglutination

Question 13

Which blood type is the universal donor and the universal recipient

Answer 13

Universal donor: O
Universal recipient : AB

Question 14

Advantage and disadvantage of specific non-specific immune response

Answer 14

Non-specific: fast, all pathogens, cannot get rid
Specific : slow, target specific pathogen, get rid

Question 15

Four jobs of T cell

Answer 15

Stimulate more phagocytosis by releasing cytokines
Helper T cell : activate B cell
Cytotoxic T cell / killer T cell : Dealing with infected cell by releasing cytotoxic chemical (Cytotoxin) (E.g. perforin)
Memory T cell: rapidly divide when previous pathogen encounter again

Question 16

Two jobs of B cell

Answer 16

Plasmid cell : make complimentary antibody agglutinate pathogens
Memory B. Cells : stay in the body allowed body produce antibody rapidly for cloning and become plasmid cell

Question 17

Whole immune response process, including B cell and T cell

Answer 17

Both T and B is out is produced by bone marrow. when invading pathogen encounter in a system, then present antigen on self surface membrane. The antigen presenting cells’ antigen will be bind with complimentary antibody chosen by clonal selection. T cell will be activated and stimulated the cell division process of mitosis, and four types of T cell will be produced.
B cell could bind with antigen in blood through it through clonal selection antigen is being internalise and present on the protein of self-surface membrane. Then T-helper cells, which is complimentary to the antigen, will bind with it. This activated B-cell, which cause division process of mitosis and two type of B cell is produce.

Question 18

Definition of monoclonal antibody

Answer 18

Cell that’s been cloned and produce same antibody that bind with same specific antigen

Question 19

What are the industry and medical used of monoclonal antibodies

Answer 19

Targeting medication to specific cell types
Medical testing
Medical diagnosis using Elisa

Question 20

Difference between direct monoclonal, antibody therapy and indirect monoclonal antibody therapy

Answer 20

Direct
Monoclonal antibodies are produced specific to the antigen on the target of cell
Prevent the cell uncontrolled growth (inhibit growth) by blocking signalling pathways in them, so they can’t divide and died
Indirect
cytotoxic, drug is attached it to the monoclonal antibody and antibody attach to the antigen on the target to kill the cell

Question 21

Pregnancy testing

Answer 21

Reaction site
Free antibody (Anti- HCG antibodies) to trap HCG
Testing site
Fixed antibodies (Anti HCG antibody) to trap HCG
CONTROL SITE
Fixed antibodies (antimouse antibodies) do you trap free excess antibodies

Liquid move up through capillary action

Question 22

How color reaction in pregnancy test happen?

Answer 22

Substrate complex with dye molecule
Turn into coloured products

Question 23

How are monoclonal antibody made artificially?

Answer 23

They are made artificially by injected, nonself cell into mouse
Fuse the plasma cell ( from the mouse) with the tumour cell
So it become hybridoma cells
Which could make more monoclonal antibody

Question 24

Describe the stages of her pregnancy test work (exam Q)

Answer 24

What in reaction site the free Ab from the mouse carry enzyme that find with HCG to the test area
In the test side if they got pregnant with enough HCG will bind with the antibody
The product of enzyme substrate complex is coloured

Question 25

Purpose of control site in pregnancy test

Answer 25

To prove if the test work Prevent false negative result

Question 26

What is the ELISA test for, equipment

Answer 26

Use for diagnosing disease like flu chlamydia hepatitis Identify the presents and concentration of an antigen or an antibody in the patient sample Who is plasma cell body fluid not the red blood cell (no colour) Use of multiwell plate

Question 27

What is the control for ELISA to test for?

Answer 27

Check colour change, only happen due to presence of enzyme no other factor Rinsing between stages are effective

Question 28

Steps of ELISA test

Answer 28

HIV, antigen molecule attaches to test well in a dish Sample of blood plasma is add to the well. If HIV antibody present they bind with HIV antigen Well is wash to remove excess antibodies A second Antibody with an enzyme attached. It is then at the spine, specifically to HIV antibody. The well is washed again to remove any unbounded Antibody Yellow solution is add Change to blue if enzyme is present HIV antibody present, HIV positive

Question 29

Ethical use of monoclonal antibodies

Answer 29

Use of mice Deliberately induce cancer, which cause suffering Death in treatment of multiple sclerosis Patient should have full knowledge of risk and benefit before giving permission (inform consent) Danger of testing the safety of new drug Sever multiple organ failure due to T cell, overproducing chemical which stimulate immune response that attack body tissue

Question 30

How do you know the concentration of antibodies elisa test?

Answer 30

Dark of the colour, high concentration of Ab

Question 31

Pros of monoclonal antibodies

Answer 31

Successfully treat a number of disease

Question 32

Vaccination

Answer 32

Injecting inactivated pathogen Double trial and lab trial, clinical trial on healthy people Create memory cell for a real infection

Question 33

Definition of vaccination

Answer 33

Involve injection of antigen that have been isolated from a dead attenuated micro organism This induced a primary immune response in an individual produce memory cells / plasma cell/ antibodies without them, suffering the symptoms of disease. Provide artificial immunity

Question 34

Describe two stages of immune responds

Answer 34

Primary: by vaccination / actual infection with pathogen Secondary responds : faster quicker/ more plasmid an antibody

Question 35

Definition of herd immunity

Answer 35

Sufficiently large proportion of the whole population has been vaccinated Set of pathogen is less easy to spread from person to person Protect those who have not been vaccinated , not immunised

Question 36

Ethical issue of using vaccines

Answer 36

Use of animal in testing Side-effect causing long-term harm How many volunteers vaccines trail risk Trial a new vaccine with unknown have only in a country where the target this is common Compulsory vaccination to be fully effective Economic concern : should expensive vaccine program, continue when a disease is almost eradicated, even though this means less money for the treatment of other disease Balance between individuals health risk and advantage for larger population

Question 37

Why vaccination might not work?

Answer 37

People with defective immune system (age /chemotherapy) Individual may develop disease , and infect the other, as there is no enough memory cell When pathogen mutate frequently is difficult to develop a vaccine against them (antigenic variability) Pathogen that hide from the immune system (HIV is hard to detect in early stages) Individual may have objection against vaccines (religious reason)

Question 38

Definition of antigenic variability

Answer 38

A pathogen mutate frequency Which can cause is surface antigen to change The Fessenden suddenly become ineffective Because the antibody of the immune system can no longer recognise / not complimentary to the antigen

Question 39

Definition of passive immunity

Answer 39

Introducing or inserting monoclonal antibody into an organism from an outside source Do you have no contact with pathogen or antigen?

Question 40

Definition of active immunity

Answer 40

Direct contact with pathogen or its antigen Stimulating the bodies immune system to produce its own antibodies

Question 41

Give examples of natural and artificial ways of giving active immunity and passive immunity

Answer 41

Active Natural : actual pathogen infection Artificial : vaccine injection of antigen Passive Natural : maternal antibodies from breast milk Artificial : blood transfusion , monoclonal, antibody injection

Question 42

Compare active and passive immunity

Answer 42

Ab secreted by plasma cell vs Ab introduced into body from outside Long-term because antibody produce in response to antigen, memories are made vs short term because no memory, made antibody will break down Takes longer to develop vs fast acting

Question 43

Feature of a successful vaccination

Answer 43

Financially available Few side-effects Ways of producing storing and transport Ways of giving administering the vaccine properly (training staff) Available in sufficient quantity to vaccinate most of the population to result in herd immunity

Question 44

Structure of HIV

Answer 44

Attachment protein Lipid envelope Matrix Capsid Genetic material (RNA) Reverse transcriptase

Question 45

What is HIV?

Answer 45

Retrovirus A group of viruses where the virus is able to insert is genetic material into the host cells DNA, using an enzyme called the reverse transcriptase

Question 46

HIV infection

Answer 46

Enter the bloodstream and circulate Virus binds using attachment protein to receptor protein (CD4) on the surface of T helper cell The virus lipid and the fused with the cell surface membrane The capsid it breaks down, and this released a genetic material and enzyme into the cell Reverse transcriptase, convert RNA to DNA The viral DNA moved into the nucleus through a nuclear pore and is inserted into the host cell DNA by integrase the HIV DNA is transcripted into mRNA, and then translate it into viral protein These new viral particles are assembled and bud off from the cell surface membrane it to infect more cell Destroy T-helper cells

Question 47

How HIV cause AIDS

Answer 47

When we are infected with HIV, we are HIV positive Normal 800 to 1200 helper T cell Abnormal 200 Immune system stop functioning, unable to produce adequate immune response Suspectible to other infection Lead to AIDS acquired immune deficiency syndrome Symptoms are related to the infection. A person developed as a result of having a damage immune system which can’t fight off infection as well. Secondary infection, cost death

Question 48

Exam Q: after being infected with HIV and number of years later, individual develop a number of Audrey infection, explain why?

Answer 48

HIV replicate, destroy helper, T cell Helper T cell number decrease Less cell to activate B cell Less plasma cell produce Less antibody made against pathogen for second infection Less memory cell made Unable to fight secondary infection

Question 49

Some important point for HIV

Answer 49

AIDS is a set of symptoms that result from low helper, T cell, number due to rapidly replicating, HIV in a patient. It is possible to be HIV positive, but not having AIDS yet People with AIDs must be HIV positive

Question 50

How does antibiotic works? Example too

Answer 50

Antibiotic works in many ways but one function they have is prevent bacteria from making cell wall. Water are consistently enter bacteria cell by osmosis. without cell wall bacteria will lysis if too much Water enters. antibiotics like penicillin, inhibit, certain enzyme required to synthesis and assembly The cross linkage in the murein cell wall. Weakening them making them unable to withstand high pressure caused by water entering the cell

Question 51

Why antibiotics does not affect the virus?

Answer 51

have no cell wall No metabolic process Cannot reach the virus getting into the cell Only Damage host cell would kill the virus

Question 52

What is antibiotic resistant and how does it develop?

Answer 52

There is genetic mutation in the base sequence Change protein Change characteristic Penicillin, kill Audiard bacteria so they can’t pass on this survive Antibiotic resistant bacteria, survive and pass on

Question 53

Two type of test statistic?

Answer 53

Standard deviation Student t-test

Question 54

Keyword for null or alternative hypothesis

Answer 54

Statistically significant difference

Question 55

Exam question asking about statistic test calculation

Answer 55

Compare P value to 0.05 Statistically significant difference or not Most significant one Reject or accept null hypothesis

Question 56

4 type of cell that can stimulate an immune response

Answer 56

Pathogen Abnormal body cell Antigen- presented cell cell from other organism of same species