1. The pictures above show a single-cell plant and an oak tree
The pictures above show a single-cell plant and an oak tree. Both of these plants need to absorb carbon dioxide for photosynthesis.
Explain why the tree needs hundreds of leaves where as the single-celled plant does not.
[6]

2. Question mark scheme (green pen time)
Levels
Expected responses
Level 3
All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling (5-6 marks)
Level 2
For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling (3-4 marks)
Level 1
Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science (1-2 marks)
Level 0
Insufficient or irrelevant science. Answer not worthy of credit.
(0 marks)
Get carbon dioxide by diffusion
Single celled plant can take carbon dioxide in by diffusion without help
Tree is a lot bigger than the single-celled plant
Diffusion will be slower in the oak tree than the single celled organism
Higher Level Answers
The oak tree will have a smaller surface area to volume ratio than the single celled organism
Diffusion will be too slow for the tree
The leaves have a larger surface area to volume ratio to allow diffusion to be faster

8. Levels Expected responses Level 3
Processes used for obtaining specified materials are given and correctly linked to the vessels that the materials are transported in (5-6 marks)
Level 2
At lease one process for obtaining a specified material is given and is correctly linked to the vessel that the material is transported in or correctly describes the direction of movement of a material (3-4 marks)
Level 1
At least one process (P) js given for obtaining a material or at least on vessel (V) or there is a description of the direction of movement (M) for at least one material(1-2 marks)
Level 0
Insufficient or irrelevant science. Answer not worthy of credit.
(0 marks)
Examples of points made in response ions:
(P) Taken up by diffusion or active transport
From a high to low concentration (diffusion) or from low to high concentration (active transport)
(V) Travels in the xylem
(M) To the leaves or from the roots
Water
(P) Taken up by osmosis
From an area of high water concentration to an area of low water concentration
(P) Transpiration stream
Sugar
(P) Made in photosynthesis
(V) Travels in the phloem
(M) To other parts of the plant or for storage in organs

12. Abundant supply of cows So shorter waiting time
Levels
Expected responses
Level 3
There is a description of the advantages of the cow tissue valve AND disadvantages of the cow tissue valve or a description of several advantages of the cow tissue valve and at least one disadvantage (5-6 marks)
Level 2
There is a description of at least one advantage of the cow tissue valve and at least on disadvantage of the cow tissue valve(3-4 marks)
Level 1
There is a description of at least one advantage of the cow tissue valve or a description of at least one disadvantage (1-2marks)
Level 0
Insufficient or irrelevant science. Answer not worthy of credit.
(0 marks)
Advantages
Abundant supply of cows
So shorter waiting time
No need for tissue typing
Quicker operation
Less invasive or shorter recovery time
Cheaper operation costs
Less operation/anaesthetic risks
Disadvantages
Made from cow to possible objection on religious grounds
New procedure so could be unknown risks
Risks of using a stent e.g. blood clots or stent breaking
Not proven as a long term treatment
May be rejected

16. Statin/aspirin/neither recommended
no mark, may be implied, if no recommendation or implication max 4 marks
Any five from
- Argued evaluation in favour of aspirin or statin or neither
Statins
- More people in students
So data/findings are more repeatable
Reduces cholesterol but aspiring doesn’t
Aspirin may cause bleeding/ poor clotting
Smaller total percentage suffer side effects
Monitored by a doctor, aspirin isn’t
Aspirin
- Cheaper
Can be bought over the counter rather than prescribed
Statins cause serious damage/muscle damage/kidney failure, aspirin doesn’t
Similarities
- Both have similar effect on reducing (non-fatal) heart attacks
- Incidence of side-effects is low in both