One to four mark questions will start with command words such as 'describe' or 'explain'. Some command words are easy to understand such as:
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.
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
Complete the sentences using the terms below.
pairs, proteins, inherited, DNA, genes
Chromosomes in body cells are found in __________. They are long strands of molecules of __________. Chromosomes have __________ which determine __________ characteristics.
Pairs, DNA, genes, inherited
In cats, the allele for short hair (D) is dominant to the allele for long hair (d).
A cat with short hair was mated with a cat with long hair. All of the offspring (F1) had short hair.
i) What are the genotypes of the parents? [1 mark]
ii) Complete the Punnett square to show the cross between the cat with short hair and the cat with long hair. [2 marks]
i) Cat with short hair - DD, cat with long hair - dd 
The cats will be homozygous as the question states that the offspring all show the dominant characteristic
One mark will be awarded if the gametes were correctly placed in the grid and another for working out the cross correctly.
Classification of the cow (Bos taurus) and a part classification of the horse (Equus ferus) are shown below.
Complete the classification of the horse in the table above. [3 marks]
Usually spelling is unimportant but if the word is already written on the page eg vertebrates, it is important that spelling is accurate.
In this case as a genus and species are required, it is important that the genus has a capital letter (Equus) and the species a lowercase letter (ferrus).
What is the difference between genotypes and phenotypes? Give an example of each in your answer. [4 marks]
In mice the allele for black eye colour (B) is dominant over the allele for red eye colour (b).
What is the phenotype of each of the following mice? [1 mark]
Mouse 1 - BB
Mouse 2 - Bb
Mouse 3 - bB
Mouse 4 - bb
Mouse 1 - BB - black
Mouse 2 - Bb - black
Mouse 3 - bB - black
Mouse 4 - bb - red
i) If mouse 1 and mouse 4 were mated together and had 12 offspring, how many of these would you expect to have black eyes?[1 mark]
ii) Complete the Punnett square below to help you answer. [1 mark]
i) 12 
How does the modern-day use of genome sequencing help us to genetically modify organisms? [3 marks]