Question 1
State the four components of blood.
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- red blood cells (1)
- white blood cells (1)
- platelets (1)
- plasma (1)
Question 2
Plasma transports many substances around the body. Give three substances that are transported by plasma.
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- carbon dioxide (1)
- digested food / glucose / amino acids (1)
- urea (1)
- hormones (1)
- heat energy (1)
- Max 3
Question 3
Which feature of a red blood cell increases the amount of oxygen it can carry?
- A large nucleus
- A thick cell wall
- Haemoglobin inside the cell
- Many mitochondria
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Answer: C (1)
Question 4
Explain how three adaptations of red blood cells make them suitable for transporting oxygen.
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- biconcave shape gives a large surface area for oxygen to diffuse in and out (1)
- no nucleus, so there is more room for haemoglobin (1)
- contains haemoglobin which combines with oxygen (1) allow forms oxyhaemoglobin
Question 5
Lymphocytes release antibodies when a pathogen enters the body. Explain why an antibody that works against one pathogen does not work against a different pathogen.
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- antibodies are specific (1)
- the shape of the antibody fits the antigen on that pathogen only (1)
- a different pathogen has different antigens, so a different antibody is needed (1)
Question 6
Biology only (what this means)
Biology only: only in International GCSE Biology. Double Award students can skip it. What the labels meanExplain how vaccination protects a person from a disease, and why the person's immune system responds more strongly to a second exposure to the pathogen.
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| Level | Marks | What the answer does |
|---|---|---|
| 3 | 5–6 | A clear, logical explanation covering the vaccine, the first response, memory cells and all three features of the faster second response (sooner, faster, greater quantity). Scientific terms are used accurately. |
| 2 | 3–4 | Explains most of the sequence, including memory cells and at least one feature of the faster response. Some steps may be missing or unclear. |
| 1 | 1–2 | Some correct points, such as the vaccine contains antigens or antibodies are made, but little explanation of memory cells or the second response. |
Indicative content
- a vaccine contains a harmless form of the pathogen (dead or weakened) with its antigens
- the antigens trigger lymphocytes to release antibodies, without the person becoming ill
- memory cells are made and stay in the body
- if the live pathogen enters, memory cells recognise it
- antibody production happens sooner
- antibodies are produced faster and in greater quantity
- the pathogen is destroyed before it can cause the disease
Question 7
Biology only (what this means)
Biology only: only in International GCSE Biology. Double Award students can skip it. What the labels meanDescribe how platelets help to prevent blood loss and infection when the skin is cut.
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- platelets collect at the wound / release chemicals (1) allow enzymes for chemicals
- soluble fibrinogen is changed into insoluble fibrin (1)
- fibrin forms a mesh that traps red blood cells to form a clot / scab (1) allow net / web for mesh
- the clot prevents blood loss and prevents entry of micro-organisms / pathogens (1)