Biology 5090 · O Level · Energy flow

Energy flow — practice question

Fig. 2.1 depicts a reindeer. Reindeer inhabit treeless regions of the Arctic. In certain months of the year, reindeer feed mainly on grasses, ferns and mosses. Wolves and brown bears eat reindeer.
(a)[4]

Construct a food web showing how energy moves between organisms in this ecosystem.

(b(i))[1]

In the remaining months of the year, reindeer eat a different food source. This food source contains a carbohydrate called lichenan. Reindeer are the only animals able to digest lichenan. List the chemical elements that are present in a molecule of lichenan.

(b(ii))[1]

State one benefit to reindeer of consuming food that contains lichenan.

(b(iii))[2]

Use your knowledge of how cell function is controlled to suggest why other animals cannot digest lichenan.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: All six organisms are shown

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI