In a monohybrid cross between two heterozygotes, what proportion of offspring are expected to be homozygous?
From Paper 2: Biological diversity
81 mark
Which genes control the development of body plans in animals?
From Paper 2: Biological diversity
91 mark
Which is an example of natural cloning in plants?
From Paper 2: Biological diversity
101 mark
In batch culture, which phase is used to harvest secondary metabolites such as penicillin?
From Paper 2: Biological diversity
111 mark
Which process converts ammonium ions to nitrite ions?
From Paper 2: Biological diversity
121 mark
Which of these is a density-independent factor?
From Paper 2: Biological diversity
131 mark
Which technique amplifies a small sample of DNA?
From Paper 2: Biological diversity
141 mark
Genetic drift has the greatest effect in:
From Paper 2: Biological diversity
19(a)5 marks
In a plant, purple flowers (P) are dominant to white (p), and tall (T) is dominant to short (t). A heterozygous purple tall plant is crossed with a white short plant. Draw a genetic diagram and give the expected phenotypic ratio.
From Paper 2: Biological diversity
19(b)4 marks
The observed numbers were 48, 12, 14 and 46 out of 120. Explain why these results suggest the genes are linked.
From Paper 2: Biological diversity
19(c)2 marks
Explain what is meant by epistasis.
From Paper 2: Biological diversity
20(a)4 marks
Explain how the lac operon allows E. coli to respond to the presence of lactose.
From Paper 2: Biological diversity
20(b)3 marks
Explain the importance of apoptosis in development.
From Paper 2: Biological diversity
21(a)4 marks
Describe how micropropagation is used to produce large numbers of plants.
From Paper 2: Biological diversity
21(b)4 marks
Compare batch and continuous culture in industrial fermentation.
From Paper 2: Biological diversity
22(a)4 marks
Explain the predator–prey relationship between snowshoe hares and lynx, including why the predator peaks after the prey.
From Paper 2: Biological diversity
22(b)4 marks
Discuss how conservation and economic needs can be balanced in a managed woodland.
From Paper 2: Biological diversity
23(a)4 marks
Describe how gene sequencing has allowed scientists to develop synthetic biology and predict protein structure.
From Paper 2: Biological diversity
23(b)*6 marks
Discuss the ethical issues raised by genetic engineering in animals and plants.
From Paper 2: Biological diversity
24(a)4 marks
Describe and explain the shape of a population growth curve for a species introduced to a new habitat.
From Paper 2: Biological diversity
24(b)4 marks
Explain what is meant by deflected succession, giving an example of how it is used in conservation.
From Paper 3: Unified biology
3(a)4 marks
Sickle cell anaemia is caused by a substitution mutation in the β-globin gene. Explain how this mutation leads to sickle-shaped red blood cells.
From Paper 3: Unified biology
3(b)4 marks
Explain why the sickle cell allele is more common in parts of Africa where malaria is common.
From Paper 3: Unified biology
3(c)3 marks
In one population, 1 in 25 babies is homozygous for the sickle cell allele. Calculate the frequency of heterozygotes.
From Paper 3: Unified biology
6*9 marks
Discuss how the structure of proteins is related to their functions in living organisms. Use examples from different areas of biology.
Score 0 / 80 · 0 of 25 marked
This paper is written by Plasmo in the style of the OCR A-Level Biology exam. It is not a past paper and is not produced or endorsed by the exam board.