AQA A Level Bio: Topic 2C - Cells and
the Immune system EXAM QUESTIONS
ADCs are molecules made of a monoclonal antibody linked to a cancer drug.
Use your knowledge of phagocytosis to describe how an ADC enters and kills the tumour cell.
3 marks - ANS - 1. Cell engulfs the ADC
2. Lysosomes fuse with vesicle
3. Releases hydraulic enzymes (lysozymes) that digest the antibody
\After a disease is diagnosed, monoclonal antibodies are used in some medical treatments.
Give one example of using monoclonal antibodies in a medical treatment. - ANS - Target/Binds
to specific cells/ antigens
IGNORE pregnancy test, ELISA test etc
\Bacterial meningitis is a potentially fatal disease affecting the membranes around the brain.
Neisseria meningitidis (Nm) is a leading cause of bacterial meningitis.
(a) In the UK, children are vaccinated against this disease. Describe how vaccination can lead
to protection against bacterial meningitis.
6 marks - ANS - 1.Antigen on surface of N. meninigitidis binds to the surface protein / surface
receptor on a (specific / single) B cell.
2. (Activated) B cell divides by mitosis / produces clone;
3. (Division) stimulated by T cells;
If answered in context of T cell, allow (Cytokine) stimulates production of plasma cells;
4. B cells / plasma cells release antibodies;
5. (Some) B cells become memory cells;
6. Memory cells produce plasma / antibodies faster
\Describe and explain the role of antibodies in stimulating phagocytosis. Do not include details
about the process of phagocytosis.
2 marks - ANS - 1. Bind to antigen
2. Antibodies cause agglutination
\Describe how a phagocyte destroys a pathogen present in the blood.
3 marks - ANS - 1. Engulfs
2. Forms vesicle and fuses with lysosomes
3. Lysosome release lysozymes that digest pathogen
\Describe how HIV is replicated
4 marks - ANS - 1. Attachment proteins attach to receptors on helper T cell/lymphocyte;
2. Nucleic acid/RNA enters cell;
3. Reverse transcriptase converts RNA to DNA;
4. Viral protein/capsid/enzymes produced;
5. Virus (particles) assembled and released (from cell);
\Describe how presentation of a virus antigen leads to the secretion of an antibody against this
virus antigen.
3 marks - ANS - 1.Helper T cell binds to the antigen (on the antigen presenting cell)
, 2. This helper T cell stimulates a specific B cell;
3. B cell clones
4. Forms plasma cells that release antibodies
3 max
\Describe how the B lymphocytes of a frog would respond to vaccination against Ranavirus.
You can assume that the B lymphocytes of a frog respond in the same way as B lymphocytes
of a human.
Do not include details of the cellular response in your answer.
3 marks - ANS - 1. B cell antibody binds to complementary receptor
2. B cell clones
3. Plasma cells release monoclonal antibodies
4. B cells produces memory cells
\Describe how the human immunodeficiency virus (HIV) is replicated once inside helper T cells
(TH cells).
4 marks - ANS - 1. RNA converted into DNA using reverse transcriptase;
Reject 'messenger' or 'm' before RNA
2. DNA incorporated/inserted into (helper T cell) DNA
3. DNA transcribed into (HIV m)RNA;
4. (HIV mRNA) translated into (new) HIV/viral proteins (for assembly into viral particles);
\Describe the difference between active and passive immunity.
5 marks - ANS - Active involves memory cells, passive does not;
2. Active involves production of antibody by plasma cells / memory cells;
3. Passive involves antibody introduced into body from outside / named source;
4. Active long term, because antibody produced in response to antigen;
5. Passive short term, because antibody (given) is broken down;
6. Active (can) take time to develop / work, passive fast acting.
5 max
\Describe the process of T cell activation - ANS - - Has receptor proteins on surface that bind to
complementary antigens on the antigen presenting cell, activates T cell
- T helper cells release chemicals that activate T cytotoxic cells
- Tc cells kill abnormal and foreign cells
-Th cells also stimulate B cells which secrete antibodies
\Describe the role of antibodies in producing a positive result in an ELISA test.
4 marks - ANS - 1. (First) antibody binds/attaches /complementary (in shape) to antigen;
2. (Second) antibody with enzyme attached is added;
3. (Second) antibody attaches to antigen;
. 4. (Substrate/solution added) and colour changes;
\Describe the role of B cells in the immune response - ANS - - Antibodies on B cell binds to
complementary antigen, activating the B cell and leads to clonal selection
- B cells divide into plasma cells that secrete antibodies specific to antigen ( monoclonal
antibodies)
- B cells divide into memory cells that provide a faster secondary response ( produces a larger
amount of antibodies in a shorter period of time)
the Immune system EXAM QUESTIONS
ADCs are molecules made of a monoclonal antibody linked to a cancer drug.
Use your knowledge of phagocytosis to describe how an ADC enters and kills the tumour cell.
3 marks - ANS - 1. Cell engulfs the ADC
2. Lysosomes fuse with vesicle
3. Releases hydraulic enzymes (lysozymes) that digest the antibody
\After a disease is diagnosed, monoclonal antibodies are used in some medical treatments.
Give one example of using monoclonal antibodies in a medical treatment. - ANS - Target/Binds
to specific cells/ antigens
IGNORE pregnancy test, ELISA test etc
\Bacterial meningitis is a potentially fatal disease affecting the membranes around the brain.
Neisseria meningitidis (Nm) is a leading cause of bacterial meningitis.
(a) In the UK, children are vaccinated against this disease. Describe how vaccination can lead
to protection against bacterial meningitis.
6 marks - ANS - 1.Antigen on surface of N. meninigitidis binds to the surface protein / surface
receptor on a (specific / single) B cell.
2. (Activated) B cell divides by mitosis / produces clone;
3. (Division) stimulated by T cells;
If answered in context of T cell, allow (Cytokine) stimulates production of plasma cells;
4. B cells / plasma cells release antibodies;
5. (Some) B cells become memory cells;
6. Memory cells produce plasma / antibodies faster
\Describe and explain the role of antibodies in stimulating phagocytosis. Do not include details
about the process of phagocytosis.
2 marks - ANS - 1. Bind to antigen
2. Antibodies cause agglutination
\Describe how a phagocyte destroys a pathogen present in the blood.
3 marks - ANS - 1. Engulfs
2. Forms vesicle and fuses with lysosomes
3. Lysosome release lysozymes that digest pathogen
\Describe how HIV is replicated
4 marks - ANS - 1. Attachment proteins attach to receptors on helper T cell/lymphocyte;
2. Nucleic acid/RNA enters cell;
3. Reverse transcriptase converts RNA to DNA;
4. Viral protein/capsid/enzymes produced;
5. Virus (particles) assembled and released (from cell);
\Describe how presentation of a virus antigen leads to the secretion of an antibody against this
virus antigen.
3 marks - ANS - 1.Helper T cell binds to the antigen (on the antigen presenting cell)
, 2. This helper T cell stimulates a specific B cell;
3. B cell clones
4. Forms plasma cells that release antibodies
3 max
\Describe how the B lymphocytes of a frog would respond to vaccination against Ranavirus.
You can assume that the B lymphocytes of a frog respond in the same way as B lymphocytes
of a human.
Do not include details of the cellular response in your answer.
3 marks - ANS - 1. B cell antibody binds to complementary receptor
2. B cell clones
3. Plasma cells release monoclonal antibodies
4. B cells produces memory cells
\Describe how the human immunodeficiency virus (HIV) is replicated once inside helper T cells
(TH cells).
4 marks - ANS - 1. RNA converted into DNA using reverse transcriptase;
Reject 'messenger' or 'm' before RNA
2. DNA incorporated/inserted into (helper T cell) DNA
3. DNA transcribed into (HIV m)RNA;
4. (HIV mRNA) translated into (new) HIV/viral proteins (for assembly into viral particles);
\Describe the difference between active and passive immunity.
5 marks - ANS - Active involves memory cells, passive does not;
2. Active involves production of antibody by plasma cells / memory cells;
3. Passive involves antibody introduced into body from outside / named source;
4. Active long term, because antibody produced in response to antigen;
5. Passive short term, because antibody (given) is broken down;
6. Active (can) take time to develop / work, passive fast acting.
5 max
\Describe the process of T cell activation - ANS - - Has receptor proteins on surface that bind to
complementary antigens on the antigen presenting cell, activates T cell
- T helper cells release chemicals that activate T cytotoxic cells
- Tc cells kill abnormal and foreign cells
-Th cells also stimulate B cells which secrete antibodies
\Describe the role of antibodies in producing a positive result in an ELISA test.
4 marks - ANS - 1. (First) antibody binds/attaches /complementary (in shape) to antigen;
2. (Second) antibody with enzyme attached is added;
3. (Second) antibody attaches to antigen;
. 4. (Substrate/solution added) and colour changes;
\Describe the role of B cells in the immune response - ANS - - Antibodies on B cell binds to
complementary antigen, activating the B cell and leads to clonal selection
- B cells divide into plasma cells that secrete antibodies specific to antigen ( monoclonal
antibodies)
- B cells divide into memory cells that provide a faster secondary response ( produces a larger
amount of antibodies in a shorter period of time)
