Six-mark questions
Six-mark questions will only appear in the Depth paper. There will be two six-mark questions in the Depth paper.
Six-mark questions are extended free-response questions, requiring the longest answers. It is wise to plan your answer rather than rushing straight into it. Without a plan it is easy to stray away from the key point and lose marks, get steps in a process in the wrong order or forget key bits of information.
To gain six marks, you will need to:
- use appropriate scientific words and terms
- write your answer in full sentences, not bullet points
- write clearly, linking ideas in a logical way
- maintain a sustained line of reasoning, rather than a random list of statements and sentences
- support explanations using scientific knowledge and understanding
Six-mark questions are marked using a levels-based mark scheme. An answer that is not clear and logically sequenced, and which does not give a coherent argument supported by evidence, will be limited to the lower levels. Similarly, if the question asks you to discuss both sides of an argument, or explain two observations, you will be limited to the lowest level if your answer only considers one of them (no matter how brilliantly written or comprehensively explained that one is).
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
Complete the cross between a male with genotype BB for brown eyes and a female with genotype bb for blue eyes. Analyse your results in terms of percentages. [6 marks]
| b | b | |
| B | Bb | Bb |
| B | Bb | Bb |
| B | |
|---|---|
| b | Bb |
| b | Bb |
| B | |
|---|---|
| b | Bb |
| b | Bb |
Answer should include most of the following points, but to score high marks you need to provide explanations and make your points in a logical order:
- 2 marks for correct Punnett square
- 100% of the offspring have brown eyes
- 0% of the offspring have blue eyes
- 100% of the offspring are heterozygous
- 0% of the offspring are homozygous recessive
- 0% of the offspring are homozygous dominant
Sample question 2 - Foundation
Question
Describe the process of selective breeding. Give examples in your answer. [6 marks]
- Decide which characteristics are important enough to select.
- Choose parents that show these characteristics from a mixed population. They are bred together.
- Choose the best offspring with the desired characteristics to produce the next generation.
- Repeat the process continuously over many generations, until all offspring show the desired characteristics.
- Examples of animals: pigs, sheep, cows, dogs or other suitable example (1 mark).
- Examples of plants: broccoli, Brussel sprouts, cabbage, cauliflower (1 mark).
Sample question 3 - Higher
Question
A heterozygous male for tongue rolling marries a homozygous recessive female. Complete a Punnett square to show their possible offspring. Analyse your results as percentages and proportions. [6 marks]
| t | t | |
| T | Tt | Tt |
| t | tt | tt |
| T | |
|---|---|
| t | Tt |
| t | Tt |
| t | |
|---|---|
| t | tt |
| t | tt |
Answer (six from):
- 2 marks for correct Punnett square (other letters are allowed)
- 50% (0.5) of the offspring could tongue roll
- 50% (0.5) of the offspring couldn't tongue roll
- 50% (0.5) of the offspring are heterozygous
- 50% (0.5) of the offspring are homozygous recessive
- 0% (0.0) of the offspring are homozygous dominant
Sample question 4 - Higher
Question
Compare the structure of prokaryotic and eukaryotic organisms. [6 marks]
The following is a list of valid points that could be included in your answer.
Note that questions with 'compare' in them will look for similarities as well as differences.
- They are both bounded by a cell membrane.
- They both have ribosomes (though they are different sizes).
- Prokaryotic organisms have a cell wall. Cell walls are also found in the eukaryotic organisms, plants and fungi.
- Prokaryotic organisms are much smaller in size than eukaryotic organisms.
- The genetic material of prokaryotic cells is a single loop of DNA that lies in the cytoplasm. In eukaryotic organisms, it is in the nucleus.
- Prokaryotic cells have additional DNA in a ring called a plasmid. Plasmids are very rarely found in eukaryotic organisms.
