QCAA Biology Alternative Sequence Genetics and heredity
1 sample question with marking guides and sample answers
Q27
2021
QCAA
Paper 1
4 marks
Q27
4 marks
The endosymbiotic theory states that eukaryotes are a product of one prokaryotic cell merging with another prokaryotic cell.
Describe two features of eukaryotic cells that support this theory.
Reveal Answer
Eukaryotic cells can contain mitochondria and chloroplasts, thought to be derived from this endosymbiotic event.
Most mitochondria and chloroplasts are thought to have evolved from an ancient bacterium as they have two membranes. They also divide by a process similar to binary fission.
Marking Criteria
| Descriptor | Marks |
|---|---|
identifies a feature | 1 |
describes how this feature supports the theory | 1 |
identifies a second feature | 1 |
describes how this feature supports the theory | 1 |