Biology 9700 · AS & A Level · Testing for biological molecules
Testing for biological molecules — practice question
The humpback whale, Megaptera novaeangliae, ranks among the largest mammals on Earth. It may reach a length of up to 15 metres and a mass of up to 36 00 kg. Much of a humpback whale’s mass is a very thick under-skin layer of fat-containing cells known as blubber. Humpback whales are seasonal feeders. They feed in polar regions during summer and then travel to warmer temperate and tropical waters to mate and produce their young during the polar winter.
(a(i))[1]
Put arrow heads on the lines in Fig. 3.1 to indicate the direction of energy transfer in the food web.
(a(ii))[1]
State the trophic level that the humpback whale belongs to.
(a(iii))[3]
In energy-transfer terms, explain why the humpback whale can grow to such a large size.
(b)[2]
The thickness of blubber in humpback whales falls during the non-feeding season and rises during the feeding season. Suggest explanations for this observation.
(c)[3]
Describe the roles of water as an environment for organisms, such as those shown in Fig. 3.1.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “all arrows are pointed correctly in food chain” …