The diagrams show three different bonds.
Which bonds are found in an antibody molecule?
Options
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
Specific monoclonal antibodies can be used to treat some forms of cancer. One example is trastuzumab, which can be used in the treatment of tumours caused by cancer.
Which statements could help to explain why monoclonal antibodies such as trastuzumab are suitable for this role?
1 The variable regions of monoclonal antibodies such as trastuzumab can change, allowing the antibodies to bind to cancer cells even if their antigens mutate.
2 Monoclonal antibodies such as trastuzumab bind to specific cell surface receptors on cancer cells, which prevents these receptors from receiving signals that are needed for cancer cells to grow and divide.
3 The antigen-binding sites of monoclonal antibodies such as trastuzumab are complementary to antigens found on some cancer cells, and have stable tertiary structures that do not change.
Options
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
The HIV virus causes illness by infecting and destroying T-helper cells. This leads to AIDS and an inability to produce an effective immune response.
Which components of the immune system are produced less effectively when AIDS develops?
1 memory cells
2 plasma cells
3 antibodies
Options
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
Tetanus is an infectious disease caused by a type of bacterium. This bacterium produces a protein that is a toxin which causes illness.
Scientists have produced a vaccine for tetanus which contains a harmless form of the toxin called a toxoid.
The toxoid is produced by mixing the toxin with the chemical formaldehyde. This chemical binds to the toxin making it harmless.
Which statement about the tetanus vaccine is correct?
Options
A After vaccination, the toxoid in the vaccine will be ingested by neutrophils and displayed in their cell surface membranes.
B The tetanus vaccine containing the toxoid does not contain antigens because it does not contain any cells of the pathogen.
C The toxoid protein in the vaccine stimulates the production of antibodies which remain in the blood to provide long-term immunity.
D When formaldehyde binds to the toxin, it causes the toxin to completely change shape.
What is an effect on the immune system of a reduced number of T-helper cells?
Options
A a decrease in the destruction of infected body cells by T-helper cells
B a decrease in the activation of B-lymphocytes
C an increase in the activation of T-killer cells
D an increase in the production of plasma cells
The diagrams show three types of blood cells, which are all drawn to the same scale.
Which row shows the characteristics of the cells?
Options
| name of blood cell X | engulfs pathogens by endocytosis | each responds to one antigen | |
|---|---|---|---|
| A | monocyte | Y | Z |
| B | monocyte | Z | Y |
| C | lymphocyte | Y | Z |
| D | lymphocyte | Z | Y |
The statements describe the phagocytosis of a bacterium by a macrophage.
1 Digestive enzymes break down the bacterium.
2 Lysosome fuses with the vacuole.
3 Macrophage displays the bacterial antigens on its cell surface membrane.
4 Macrophage engulfs the bacterium and encloses it in a vacuole.
5 Receptors on the cell surface membrane of macrophage bind to the bacterium.
Which order is correct for phagocytosis?
Options
A
B
C
D
Two people, G and H, were each given an injection to protect them against a particular pathogen.
One person was injected with antibodies. The other person was injected with a vaccine.
The graph shows the concentrations of the antibody against this pathogen in the blood of the two people, G and H, during a period of 20 days after their injections.
Which row correctly describes the type of immunity shown by G and H?
Options
| G | H | |
|---|---|---|
| A | artificial active immunity | artificial passive immunity |
| B | artificial passive immunity | artificial active immunity |
| C | natural active immunity | natural passive immunity |
| D | natural passive immunity | natural active immunity |
The diagram shows the structure of an antibody.
Which statements about the antibody are correct?
1 X has a similar shape to the antigen.
2 Y is the hinge region held by disulfide bonds.
3 Z is a constant region which binds to receptors on B-lymphocytes.
Options
A 1 and 2
B 1 and 3
C 2 and 3
D 2 only
Some events that happen during phagocytosis are listed.
1 Molecules on the surface of a pathogen bind to the cell surface membrane of a phagocyte.
2 Endocytosis takes place forming a specialised vesicle.
3 Enzymes catalyse hydrolysis reactions.
4 Lysosomes migrate through the cytoplasm and fuse with an organelle.
What is the correct order of these events during phagocytosis?
Options
A 1 → 2 → 4 → 3
B 1 → 4 → 2 → 3
C 3 → 2 → 4 → 1
D 3 → 4 → 2 → 1