Gibberellin plays a part in the germination of barley seeds. In one investigation, aleurone layers were taken from barley seeds. One group was exposed to gibberellin, whereas the other group received no gibberellin treatment. The rate at which amylase enzyme was made by the aleurone layers was tracked for 15 hours. The findings are presented in Fig. 7.1.
(a)[3]
Describe what the results in Fig. 7.1 show.
(b)[3]
Explain why barley seed aleurone layers must make amylase during germination.
(c(i))[1]
State the symbol used for the dominant allele.
(c(ii))[2]
Explain how this dominant allele causes active gibberellin to be produced.
(c(iii))[2]
Active gibberellin promotes stem elongation by causing DELLA protein repressors to be broken down, which allows growth genes to be expressed. Suggest the effects of the expression of these growth genes.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Amylase production rate is greater in the gibberellin-treated sample” …