Three- and four-mark questions
You will be expected to write in more depth for three- and four-mark questions. They might ask you about a process such as cloning or compare differences, such as with microscopes.
The answers here give lists of valid points that could be included in your answer. In your answers in an exam, it is important that you do not bullet point them, but link your ideas together.
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
Sample question 1 - Foundation
Question
Describe the process of cloning and how it can help to prevent plant species from becoming extinct.
[4 marks]
- cells removed from the meristem of plant (that is being protected from extinction)
- culture the cells in sterile cell/tissue culture medium
- plantlets produced are transferred to pots
- more individuals of the plant species are produced without the plants having to reproduce sexually (which takes time or there may not be another individual available)
Sample question 2 - Foundation
Question
Describe how a sperm cell is adapted to its role.
[4 marks]
Four marking points from:
- role is to fertilise an egg
- the head has the nucleus, which contains the male genetic material
- it has a tail for swimming
- the acrosome has enzymes so that the sperm can penetrate the egg
- it is packed with mitochondria to supply the energy for movement
Sample question 3 - Higher
Question
Describe the similarities and differences between the processes of diffusion and osmosis.
[4 marks]
Four marking points from:
- all gases and liquids move by diffusion
- only water moves by osmosis
- molecules move from high to low concentration in both processes
- this means molecules move down a concentration gradient
- osmosis must occur across a partially permeable membrane
- neither process requires energy
Sample question 4 - Higher
Question
Compare the advantages and disadvantages of light and electron microscopes.
[4 marks]
- electron microscopes have higher magnification
- electron microscopes have higher resolution
- scanning electron microscopes can be used to examine the surface structure of cells/structures
- light microscopes can be used to examine living cells, electron microscopes cannot
