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A Level Biology - Cells > Cell Recognition And The Immune System > Flashcards

Cell Recognition And The Immune System Flashcards

1
Q

Proteins on molecules enable the immune system to identify …x4

A

Pathogens
Cells from other organisms of the same species
Abnormal body cells
Toxins

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2
Q

What is an antigen

A

Foreign protein generate an immune response when detected by lymphocytes in the body

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3
Q

Define a pathogen

A

A microorganism that can cause diseases

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4
Q

Name x4 types of pathogen

A

Bacteria
Virus
Fungi
Protists

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5
Q

What are abnormal body cells

A

Cancerous or pathogen infected cells that have abnormal antigens on their surface that trigger an immune response

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6
Q

Are toxins molecules or cells

A

Molecules

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7
Q

Why can antigen variability be a problem

A

Antigens change frequently due to mutations
This is a problem because lymphocytes and memory cells produce a specific immune response
Bind to one antigen once changed it can no longer bind

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8
Q

What is the bodies first line of defence

A

Skin

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9
Q

Which white blood cells which are specific and which are non-specific

A

Phagocytes - non-specific
Lymphocytes- specific

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10
Q

What type of white blood cell is a macrophage

A

Phagocytes

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11
Q

Is phagocytosis specific or non-specific

A

Non-specific

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12
Q

Where are phagocytes found

A

Tissue
Blood

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13
Q

Stage 1 of phagocytosis

A

Pathogens release chemicals
Phagocytes follow the trail and moves towards these cells
The phagocytes have many receptors that will attach to the chemicals or antigens on the pathogen
The phagocyte changes shape to move around and engulf the pathogen
Once engulfed the pathogen forms a phagosome and fuses with a lysosomes
The lysozymes digests the pathogen
The phagocyte then presents the pathogens antigens on it surface to activate other immune system cells.
The phagocyte is an anti-gen presenting phagocyte

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14
Q

What is the purpose of disulphide bridges in a antibody

A

Joins two polypeptide chains

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15
Q

What type of cell are T-lymphocytes

A

White blood cell

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16
Q

Are T-cells specific or non-specific

A

Specific

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17
Q

Where are lymphocytes made

A

In bone marrow

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18
Q

What is cell-mediated response

A

The response involves T-cells and body cells
No antibodies

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19
Q

What is an antigen presenting cell

A

Any cells that presents a non-self antigen on the cell MEMBRANE

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20
Q

Name x2 antigen presenting cells

A

Macrophages
Cancer cells

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21
Q

How do T-cells work

A

They have receptors which attach onto the antigens on an antigen-presenting cell
One attached they are activated and divide by mitosis to produce large number of clones
The cloned helper T-cells differentiate into different cells

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22
Q

What can T-cells do x3

A

Helper T-Cells stimulate phagocytes
Activate B-cells to secrete anti toxins
Cytotoxic T-Cells kill foreign cells

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23
Q

How do cytotoxic T-Cells work

A

Release perforin which embeds into cell surface membrane and make a pore
Because any substance can leave or enter the cell dies

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24
Q

Are B-lymphocytes specific or non-specific

A

Specific

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25
What does humoral response involve
B cells Antibodies
26
How do B-Cells work
Antigens binds to antibody on B-cells B cell takes in antigen by endocytosis then presents it on its cell surface membrane BCells collide with T-cells receptor which activates B-cell to go through clonal selection It undergoes mitosis to make cells that differentiate into plasma cells or memory B-cells
27
What do memory B-cells divide into
Plasma cells
28
What type of protein structure are antibodies
Quaternary 4 polypeptide chains
29
Structure of antibodies
Light chain Heavy chain Variable region
30
What binds are in an anti body
Disulphide bridges
31
What is agglutination
Antibodies have 2 binding sites so can bind to 2 antigens This causes the pathogens to be clumped together
32
Advantage of agglutination
Makes it easier for phagocytes to locate and destroy pathogens
33
What is passive immunity
When antibodies made by a different organism are added to the body
34
Two types of passive immunity
Natural - E.g. antibodies through mothers milk Artificial - E.g. injected with antibodies
35
Two types of active immunity
Natural - become immune after catching a disease Artifical - immune after been given a vaccination
36
Active vs passive immunity x4 differences
Expose to antigen needed vs non expose needed Take time for protection to develop vs immediate Memory cells produced vs no memeory cells Protection long term vs short term
37
X2 uses of monoclonal antibodies
Pregnancy tests Anti-cancer drugs targeting cancer cells
38
Where does HIV replicate specifically
In helper T-Cells
39
How does direct ELISA test work
Add antigen of pathogen to the well Add antibody with enzyme attached and complimentary shape to the antigen being tested Wash the well to remove unbound antibody Substrate for the enzyme is added If detection antibody is present the enzyme reacts with substrate to give colour change
40
Explain indirect Elisa test
HIV antigens bound to the bottom of the well Sample of blood plasma is added If HIV specific antibodies are present they will bind to to HIV antigens Wash well Second set of antibodies complimentary to specific HIV antibodies are added Well is washed Substrate is added if solution changes colour than HIV specific antigen a re present and patient has HIV
41
How is HIV replicated x5
Attachment protein attach to receptors on lymphocytes Capsid and RNA enters cell Reverse transcriptase converts RNA to DNA Viral proteins produced Virus particles assembles and are released from cell
42
What further test can be done to investigate effectiveness of monoclonal antibody x2
Test on other mammals to check for side effects Test on healthy humans for side effects Investigate difference concentration to find suitable dosage
43
How does HIV replicate once inside the cell detail x4
RNA is converted to DNA using reverse transcriptase DNA is incorporated into the helper T-Cell DNA DNA is transcribed into HIV mRNA HIV mRNA translated into viral proteins
44
How can determining the genome of a virus could allow scientist to develop a vaccine
Could identify proteins They could then identify the antigens to use in the vaccine
45
How do B cells work
B cell antibody bond to the pathogens complimentary antigen The B cell the clones The plasma cells releases antibodies B cell the develops into memory cells
46
What is a monoclonal antibody
Antibody produced from cloned plasma B cell
47
Why is vaccine nation quicker upon re infection
B cells specific to antigen produced by mitosis B cells produce plasma and memory cells The second set of antibodies produced at a higher concentration and more quickly
48
How does a antigen presenting cell stimulate the production of an antibody against a virus antigen x4
Helper T-Cell binds to the antigen on the antigen presenting cell The helper T-cell stimulates a specific B cell B cell divides by mitosis To produce plasma cells that release antibodies
49
What is an antibody
A protein specific to an antigen that is produced by B cells
50
Types of phagocytes
Macrophages Neutrophils
51
What is the difference between macrophage and neutrophil
Macrophages can become and antigen presenting cell But both still carry out phagocytosis
52
What do phagocytes release after engulfing a pathogen and what is its role
Chemical can cytokines Signals to other phagocytes and the immune system cells to the site of infection
53
What 3 things does the specific immune system involve
Antibodies B and T lymphocytes
54
What type of proteins are antibodies
Glycoproteins
55
Which cell produces antibodies
B lymphocytes
56
Antibodies are part of the ….. response
Humoral
57
What type of response is Tcells and why
Cell mediated response On respond to antigens presented on antigen presenting cells
58
X4 role of T-cells
Activate B lymphocytes Stimulate macrophages to perform phagocytosis Some became memory cells Some become cytotoxic T -cells
59
How does vaccine lead to production of antibodies x5
Vaccine contains antigen from pathogen Macrophages present antigen on its surface Specific helper T-cells with complimentary receptors proteins bind to antigen T-cells stimulate B cells B cells divide to give plasma cells B cells secrete large amount of antibodies B cells divide to form clone which secrete the same antibody
60
Difference between active and passive immunity x5
Active in loves memory cells passive does not Active involves production of antibody by memeory cells passive does not Passive involves introduction of antibody from outside sources Passive is short term because antibody is broken down
61
Advantage of programmed cell death
Prevents virus replicating
62
Antibodies are which biological molecule
Protein
63
E all in how antigen binds to antibody (using key words)
Antibody has specific TERTIARY structure Has BINDING SITE that only binds to one ANTIGEN Antigen to this antibody is ONLY found on these cells So antibody BINDS to form ANTIGEN-ANTIBODY COMPLEX

A Level Biology - Cells (6 decks)

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