Topic 2C: Cells and immune System

Question 1

What is herd immunity

Answer 1

When those who aren’t vaccinated are protected against as most of the population in vaccinated so less people catch it from

Question 2

What’s a disadvantage to taking vaccines orally

Answer 2

It could be broke down by enzymes in the gut or be too large for it to be absorbed into the blood

Question 3

Name and explain an ethical issue surrounding vaccines (2)

Answer 3

All vaccines are tested on animals before humans and these may have side effects for people making them reluctant to take it

Question 4

What is antigenic variation

Answer 4

When some pathogens change their surface antigens so the memory cells from the first reaction doesn’t recognise them

Question 5

What are the different strains of influenza known as…

Answer 5

Immunologically distinct

Question 6

What’s an ethical issue with monoclonal antibodies

Answer 6

Animals rights issues and used to produce the cells

Question 7

What does HIV stand for

Answer 7

Human immunodeficiency virus

Question 8

What does AIDS stand for

Answer 8

Acquired immune deficiency syndrome

Question 9

What is AIDS

Answer 9

Condition where the immune system deteriorates and eventually fails

Question 10

What’s the cellular response

Answer 10

T-cells and other immune system cells they interact with

Question 11

What’s the humoral response

Answer 11

B-cells and clonal selection and the production of MCA’s

Question 12

Explain the primary response

Answer 12

when antigens enter the body for the first time activating immune system
It’s slow as there isn’t many B-cells making the antibodies bind to it
Person shows signs of disease
After being exposed to the antigen T and B cells produce memory cell

Question 13

Explain the secondary response

Answer 13

If the same pathogen enters the body again, immune system will produce a quicker, stronger immune response
Clonal selection occurs faster, memory cells are activated dividing into correct plasma cells producing correct antibodies
No symptoms shown

Question 14

What is active immunity

Answer 14

Type of immunity when you immune system makes its own antibodies after being stimulated by an antigen

Question 15

What’s a natural example of active immunity

Answer 15

Becoming immune after catching the disease

Question 16

What’s an artificial example of active immunity

Answer 16

When you become immune after being given a vaccination

Question 17

What’s passive immunity

Answer 17

Type of immunity you get from being given antibodies make by a different organism

Question 18

What’s a natural example of passive immunity

Answer 18

When a baby becomes immune due antibodies it received from its mother

Question 19

What’s an artificial example of passive immunity

Answer 19

When you become immune after being injected with antibodies from someone else

Question 20

Name 3 other characteristics of active immunity

Answer 20

Requires exposure to antigen
Takes awhile for protection to develop
long-term as memory cells are produced

Question 21

Name 3 other characteristics of passive immunity

Answer 21

Doesn’t requires exposure to antigen
Protection is immediate
Short-term as memory cells aren’t produced

Question 22

What’s a vaccination

Answer 22

An ingestion containing dead or weakened form of a pathogen (antigen) causing your body to produce memory cells against the pathogen

Question 23

How are monoclonal antibodies formed

Answer 23

Activated b-cells divided into plasma cells which secrete loads of antibodies which are specific to particular antigen (MCA)

Question 24

What’s agglutination

Answer 24

An antibodies has 2 binding sites, so can bind two pathogens at the same time becoming clumped together

Question 25

What’s a T-cell

Answer 25

Type of WBC, it has receptor proteins on its surface that bind to complementary antigens on pathogen (activating t-cell)

Question 26

Name 2 types of T-cell

Answer 26

Helper and Cytotoxic T-cells

Question 27

What do helper t-cell do

Answer 27

T helper cells released chemical signals that activate and stimulate phagocytes and T-cells

Question 28

What do cytotoxic t-cells do

Answer 28

Kill abnormal and forging cells also activating b-cells

Question 29

What are B-cells

Answer 29

WBC covered in antibodies

Question 30

What’s clonal selection

Answer 30

When antibodies on the surface of B-cells meet a complementary shaped antigen, it binds to it
This together with substances released from helper T cells activated b-cells

Question 31

What do b-cells divide into

Answer 31

Plasma cells

Question 32

What are antigens

Answer 32

Molecules that can generate an immune sytem

Question 33

What are pathogens

Answer 33

Organisms that cause disease

Question 34

What are toxins

Answer 34

Poisons, not cells there molecules

Question 35

Name 4 main stages of immune response

Answer 35

Phagocytes, t-cells, b-cells and antibody production

Question 36

What is a phagocyte

Answer 36

WBCs that carries out phagocytosis

Question 37

Explain phagocytosis

Answer 37

1) phagocyte recognises the foreign antigens on the pathogen
2) cytoplasm of pathogen moves round the pathogen, engulfing it
3) pathogen contained in a phagocytise vacuole
4) lysosomes fuses with vacuole, breaking down the pathogen, digestive enzymes lysosomes do this
5) phagocyte then presents pathogens antigens, activating other immune responses

Question 38

How does AIDS progress

Answer 38

Initial symptoms include minor infections of mucus membranes recurring respiratory infections later on TB
Chronic diarrhoea in the lasts stages toxoplasmosis

Question 39

How do antibiotics kill bacteria by interfering

Answer 39

Kill bacteria by interfering with their metabolic reactions

Question 40

How does HIV infect out cells

Answer 40

Infects t helper cells which act as a host cell for the virus
Affecting the effectiveness of the immune system

Question 41

How do people infected with HIV develop AIDS

Answer 41

When the he,per T cells number in the body reach a critically low level

Question 42

What’s reverse transcriptase needed for

Answer 42

Viral replication

Question 43

What’s the envelope in HIV made from

Answer 43

Made from membrane stolen from cell-membranes of a pervious host cell

Question 44

Explain how HIV replicates

Answer 44

1) attachment protein attachments to a receptor molecule on the cell membrane of the host Th cells
2) capsid is released into the cell where it uncoats and releases the genetic material into cells cytoplasm
3) Inside the cell, reverse transcriptase is used to make a complementary stand of DNA from the viral RNA template
4) Double stranded DNA is made and inserted into human DNA
5) Host cell enzymes are used to make viral proteins from viral DNA in the human DNA
6) Viral proteins are assembled into new viruses, which bud from cells and infect others

Question 45

Explain how to target a particular substance for medical diagnosis (pregnancy testing)

Answer 45

1) Application area contain antibodies for hcg bound to a colour bead (blue)
2) when urine is applied to application area any hcg will bind to the antibody on the beads, forming AA complex
3) When the urine moves it caries the beads up the test strip with it
4) test strip contains antibodies to hcg that are immobilised
5) if hcg is present the test strip turns blue, as the immobilised antibody binds to any hcg concentrating the hcg antibody complex with the blue beads attached. If no hcg is present, the beads will pass through the test trip without binding to anything and so it wouldn’t go blue

Question 46

Explain how we can target drugs to a particular cell type (cancer)

Answer 46

1) different cells in the body have different surface antigens
2) cancer cells have antigens called tumour markers that aren’t found on normal body cells
3) Monoclonal antibodies can be made that will bind to the tumour markers
4) You can also attach anti-cancer drugs to the AB’s
5) when the AB’s come into contact with the cancer cells they will bind to the tumour markers
6) meaning the drugs only accumulate in the body where the cancer cells are
7) means side effects are lower in this treatment

Question 47

Explain the ELISA test (HIV)

Answer 47

1) HIV antigen bound to the bottom of a well plate
2) sample of patients blood plasma which might contain several different antibodies, is added to the well if there are any HIV-specific antibodies they will bind to HIV antigen stuck to the HIV antigen stuck to the bottom of the well. well is washed out to remove any antibodies that unbound
3) Secondary antibody that has a enzyme attached is added to the well it can bind to HIV specific antibody well is washed again to remove any unbound secondary antibodies
4) solution is added to the well containing a substrate which is able to react with the enzyme attached to the secondary antibody to produce colour change (indicating HIV infection)