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Biology A Level - Cells > Immunity > Flashcards

Immunity Flashcards

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1
Q

What are the physical barriers that protect your body from pathogens?

A
  • skin
  • stomach acids
  • gut and skin flora
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2
Q

What are antibody?

A
  • a protein/immunoglobin
  • produced by B Lymphocytes in response to the complimentary/ specific antigen
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3
Q

What is an antigen?

A
  • a protein/glycoprotein
  • on the cell surface membrane of invading microorganisms, virus infected cells, cancer cells and allegens
  • stumilates an immune response
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4
Q

What are phagocytosis?

A

a non-specific process in which white blood cells engulf pathogens thus destroying them

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5
Q

Descibe the process of phagocytosis?

A
  1. pathogen recognised as foreign
  2. pathogen attracts phagocyte with it’s toxins
  3. phagocyte’s receptors attatch to the pathogen’s antigens
  4. phagosome forms and engulfs pathogen
  5. lysosomes containing hydrolitic enzymes fuses with the phagosome
  6. the enzymes brak down the pathogen
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6
Q

What happens after phagocytosis?

A

the phagocyte presents the pathogen’s antigen on it’s surface membrane which begins the immune response if it’s foreign.

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7
Q

What is an immune response?

A

the way in which your body response to pathogens in order to destroy, expell or prevent them from entrining the body

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8
Q

Why are antibodies specific?

A

they are complememntary with only one antigen

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9
Q

What is a pathogen?

A

a microorganism that can bring about disease

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10
Q

What are 4 types of pathogens (and exacmples)?

A
  1. bacteria (Salmonella)
  2. virus (HIV/AIDS)
  3. protist (Malaria)
  4. fungi (rose blackspot)
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11
Q

How are diseases transmitted

A
  1. infacted bathing or drinking water
  2. aiir droplets inhales (coughing and sneezing)
  3. touching infected surfaces
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12
Q

What is a specific immune response

A
  • an antigen specific
  • that produces responses specific to one type of pathegen
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13
Q

What is a non-specific immune response?

A

a response from the timmune system that responds to any type of pathogen

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14
Q

What are the types of specific immune response?

A
  1. humoral
  2. cell mediated
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15
Q

Describe the process of a humoral response?

A
  1. B-cell is triggered by it’s complementary antigen
  2. it engulfs and digests antigen
  3. it then displayed antigen fragment on it’s specific MHC molecules
  4. complementary matured T-cell is attracted to combined antigen and MHC
  5. T-cells secrete cytokines
  6. cytokines help the B-cells to multiply and mature into antibody producing cells
  7. antibodied is released into the blood to bind to complementary antigens
  8. antigen-antibody complexes cleared by cascade or liver and spleen
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16
Q

Describe the process of a cell mediated response?

A
  1. macrophage engulfs microbe and ingests it’s antigens
  2. it then processes and the presents them to the T-cells
  3. the T cell then produces clones and these clones act as 4 different types of cells
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17
Q

what type of cells does the T-cell clones become (and what do they do)?

A
  1. killer T-cell (destroys antigens)
  2. helper T-cells (stimulates T and B cells)
  3. supressor T-cells (inhibits T and B cells)
  4. memory T-cells (remembers antigen)
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18
Q

Describe the structure of an antibody.

A
  • made of four polypeptides chains forming a Y shaped structure
  • have antigen binding sites in order to make antigen-antibody complexes
  • binding site made up by the variable region
  • has a constant region
  • has a hind region
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19
Q

How does the structure of antibodys make them different/specific?

A
  1. they have variable regions which are different for each antibody
  2. they have flexible hind region so the distnace between the binding sites to vary
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20
Q

What is the constant region

in an antibody’s structure

A

the area in the antibody’s structure that is the same in ever antibody

21
Q

What are the roles of antibodies?

A
  1. tags foreign bodies/antigens for the phagocyte to digest
  2. sticks pathogens together so easier for phagocyte to find
  3. stick to bacteria toxins so they don’t harm other cells (they act as antitoxins)
  4. stick to viruses so it doesn’t invade host cells
22
Q

How does the variability of antigens affect the accuracy of vaccines?

A
  • Vaccines ensures that if there is a memory cell to prevent future infections.
  • This means it relies on the assumption that if there is a second infection, then the same antigen will be present on the pathogen.
  • If the antigen changes the memory cells are ineffective and so is the vaccine.
23
Q

What is the primary response?

A

it’s the reponse produced when your body is first exposed to the disease

24
Q

W

What are the features of a primary response?

A
  • slower
  • less antibodies produced
25
Q

What is the secondary response?

A

it’s the reponse produced when your body recognises that they’ve encountered the disease before

26
Q

What are the features of a secondary response?

A
  • faster
  • lots of antibodies produced
27
Q

How do vaccines produce a primary response?

A
  • it introduces a dead or inactive pathogen with the antibody from the diease you’re vaccinating for
  • this stimulates the immune response
28
Q

How do vaccines produce a secondary response?

A
  • memory cells and plasma are produces as a result of the primary response which makes the response (secondary) the next time you’re infected faster as your body is familiar with the antigen now
29
Q

What is herd immunity?

A

A type of disease immunity that occurs when a large proportion of a population are vaccinated against a disease which prevents the spread of the disease to unvaccinated individuals.

30
Q

What is active immunity?

A

results from the production of antibodies by the immune system in response to the presence of an antigen

31
Q

What is passive immunity?

A

results from the introduction of antibodies from another person or animal

32
Q

What are the subtypes of immunity?

A
  1. natural
  2. artfificial
33
Q

What is natural immunity?

active and passive

A
  • Natural active immunity arises from being exposed to an antigen/getting the disease
  • natural passive immunity is the result of crossing of mother’s antibodies through the placenta and their presence in breast milk
34
Q

What is artificial immunity?

active and passive

A
  • Active artificial immunity is acquired through vaccinations which stimulate the immune
    system and lead to production of antibodies
  • passive artificial immunity is where
    antibodies are injected into the body
35
Q

What affects the success of vaccinations

A
  • Cost of the vaccine
  • Severity of the side effects
  • Ease of production, transportation and administration
  • Number of people who need to be vaccinated for herd immunity
36
Q

What ethics do you have to consider when you make a vaccine?

A
  • Production and testing of vaccines may be done on animals
  • The risks of the vaccine need to be balanced with the benefits
  • The vaccine must be tested on humans first to determine toxicity
  • Vaccinations are very expensive
  • Should vaccinations be compulsory or should people be able to opt out of having a vaccination?
37
Q

What are the types of ways that monoclonal antibodies can be used?

A
  1. Direct Therapy
  2. Indirect Therapy
  3. Diagnosis
  4. Pregnancy Testing
38
Q

How can monoclonal antibodies be used in direct therapy?

A

The antibody would be used to target the sepcific antibodies on the surface of cancerous cells

examples of monoclonal antibodies and cancer could be hepetin and breast cancer

39
Q

How can monoclonal antibodies be used in indirect therapy?

A

the drug is attached to the monoclonal antibody which directs the drug to the cancerous cell with the complementary antigen

an example of a type of drug that could be attached to the antibody is a cytotoxic drug

40
Q

How can monoclonal antibodies be used in diagnosis?

A

antigen is targetted by it’s complementary monoclonal antibody to measure the level of antigen in the body

41
Q

How can monoclonal antibodies be used in pregnancy testing?

A

monoclonal antibodies in home pregnancy kit is complementary with the pregancy hormone human chronic gonadotrophin

42
Q

Describe the process of HIV replication.

A
  • attachment protein binds to CD4 (usually on T helper cells)
  • lipid envelope fuses with host cell membrane
  • capsid and components entre host cell
  • reverse transciptase changes HIV RNA to DNA
  • DNA moves into host cell nucleus and integrates with host DNA
  • viral DNA stays dormant and then becomes active
  • DNA then produces mRNA and RNA genomes which then moves into cytoplams
  • mRNA is then translated by ribosomes to viral proteins
  • viral particles assemble and bud from the host cell membrane creating the lipid envelope
43
Q

How does HIV become AIDS?

A
  • the replication process causes the death of T helper cells (host cells of replication)
  • this causes the a reduces number of T cells that can produce B cells that make antibodies used in immune responses
  • this makes your body more suseptable to infections as your immune system can no longer function effectively
44
Q

What is an ELISA?

A

it’s a test that measures the amount of antigens present on HIV

45
Q

Describe how ELISA works?

A
  • sample containing antigen is placed in well
  • antigen sticks to the bottom
  • well is washed to remove unstuck antigens
  • 2 antibodies specific to antigen added to well
  • wait and allow antigen-antibody complexes to form
  • wash to remove excess antibodies
  • second antibody with attached enzyme that’s complementary with original antibody put in well
  • antibody1 and antibody2 bind
  • well is washed to remove unbound antibody2
  • an uncoloured substrate for enzyme added
  • enzyme-substrate complex forms and product molecule formed
  • product formed is coloured
46
Q

How does ELISA show a positive result?

A

The intensity of colour depends on how many enzymes are present in the solution which depends on the number of antigens present. Therefore the more antigens from the disease the more vibrant the colour

this also makes it a quantitative test

47
Q

Why do you use multiple dilutions in ELISA?

A
  • because we want all the antigen to stick to the bottom of the well
  • if there are too many then the antigen won’t stick and there won’t be accurate results
  • so having different dilutions prevent this
48
Q

What’s a strength of ELISA?

A
  • they are automated which means many samples are read accurately, making the reults more accurate
  • makes it valuable in testing for infectious diseases like HIV
49
Q

What are the ethical issues with monoclonal antibodies?

A
  • New monoclonal antibody therapies are often tested on animals before they can move onto human-trials
  • animals are used to produce the cells from which the monoclonal antibodies are produced

Biology A Level - Cells (8 decks)

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