Biology 9700 · AS & A Level · Investigation of limiting factors
Investigation of limiting factors — practice question
Cotton, Gossypium hirsutum, and false flax, Camelina sativa, are cultivated in different regions of the world.
Rubisco activase is a chloroplast stroma enzyme that is required to keep a second enzyme, rubisco, functioning.
Scientists investigated rubisco activase activity in cotton and false flax across a range of temperatures.
Fig. 2.1 presents the findings.
(a(i))[4]
With reference to Fig. 2.1, Compare the results for cotton and false flax.
(a(ii))[3]
Suggest possible reasons for the differences shown in Fig. 2.1.
(b)[3]
Rubisco enzymes from cotton and false flax are active at temperatures up to $45^{\circ}\text{C}$ and denature at $45^{\circ}\text{C}$. Explain what happens to the Calvin cycle when rubisco denatures.
(c)[2]
One aim of genetic engineering is to produce crops that are heat tolerant. This means crops can grow and give a good yield at high environmental temperatures. Use the information given in Question 2 to suggest and explain one way to improve a crop’s tolerance to high temperatures.
Worked solution & mark scheme
This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: “cotton has a higher optimum temperature than flax for rubisco activase” …