One to four mark questions

One to four mark questions will start with command words such as 'describe' or 'explain'. Some command words are easy to understand such as:

  • 'calculate' or 'determine' for maths questions
  • 'complete' to fill in a gap in a table or graph
  • 'define' to give the meaning of an important word
  • 'suggest' where you use your knowledge in an unfamiliar situation
  • 'compare' where you describe the similarities and/or differences between things

The command words 'describe' and 'explain' can be confusing. If you are asked to describe a graph, you will be expected to write about its overall shape, whether it is linear or curved, the slope of gradients etc. If you are asked to explain why a pattern or trend is seen in a graph, you will be expected to use your science knowledge, not just say what you see (which is a description), eg the graph shows a steep linear increase for the first three hours because…

Explain how and why questions often have the word 'because' in their answer. Describe questions don't.

The number of marks per question part is given in this form '[2 marks]'. It is essential that you give two different answers if a question is worth two marks. Sometimes you can gain a second mark by giving the units in a calculation or stating specific data points, eg during the first two years the number of lions deceased by seven.

You will be expected to write in more depth for three and four mark questions. They might ask you about a process such as the carbon cycle or the method you would use in an experiment.

Edexcel questions courtesy of Pearson Education Ltd.

Sample question 1 - Foundation


A person has emphysema. This reduces the number of alveoli in the lungs.

Explain how emphysema would affect the amount of oxygen carried in the bloodstream. [2 marks]

  • emphysema will reduce the amount of oxygen carried into the bloodstream [1]
  • because there is reduced alveoli, which are the gas exchange surface between the lungs and blood capillaries [1]

Sample question 2 - Foundation


Give one reason why it is important that human lungs have a high surface area to volume ratio. [1 mark]

To maximise gas exchange/maximise oxygen uptake. [1]

Sample question 3 - Foundation


This figure shows the structures of an artery and a vein.

A cross-section of the blood vessels in the body

Explain how the structure of the artery is related to its function. [2 marks]

  • the artery has a thick wall/small lumen [1]
  • to carry oxygenated blood/to carry blood under high pressure [1]

Sample question 4 - Higher


This figure shows a diagram of the circulatory system of a fish.

Diagram illustrating the circulatory system in a fish

Compare the differences between the structure of the circulatory system of a fish and the human circulatory system. [4 marks]

  • the fish heart has two chambers rather than four chambers [1]
  • the fish heart only has one ventricle and one atrium rather than two ventricles and two atria [1]
  • only deoxygenated blood flows through the fish heart [1]
  • the fish heart has a single circulatory system rather than a double circulatory system [1]

Sample question 5 - Higher


Give one reason why the wall of the left ventricle is thicker than the right. [1 mark]

To pump blood around the body under higher pressure. [1]

Sample question 6 - Higher


Valves in the human heart may become damaged and no longer function.

Describe what would happen to the flow of blood in the left side of the heart if the valve between the left atrium and ventricle did not function effectively. [2 marks]

  • blood would flow backwards from the ventricle to the atrium/blood will leak through [1]
  • less (oxygenated) blood would be pumped to the body [1]