Biology 5090 · O Level · Absorption and assimilation

Absorption and assimilation — practice question

Brown bread, produced from flour milled from whole wheat grains, contains starch and fibre.
(a(i))[4]

A man eats a piece of brown bread. In his digestive system, the starch in the bread is chemically broken down first to maltose and then to glucose. Describe where and how this digestion occurs as the bread passes through his digestive system.

(a(ii))[2]

Describe what happens to the fibre as it travels through his digestive system.

(b)[2]

Glucose moves from the digestive system into the blood by diffusion and active transport. Give two ways active transport differs from diffusion.

(c(i))[1]

There is already glucose in the blood at the time the starch is eaten. Explain how Fig. 2.1 shows this.

(c(ii))[2]

Both graph lines show blood glucose concentration rising initially and then falling. Suggest two reasons for the drop in blood glucose concentrations.

(c(iii))[2]

Use the information from Fig. 2.1 to suggest which type of starch would be healthier to include in the diet. Give a reason for your answer.

(d)[4]

Scientists want to develop a new wheat variety with a higher fibre content. Describe two methods they could use to achieve this.

Worked solution & mark scheme

This 17-mark question has a full step-by-step worked solution and mark scheme. One marking point: amylase catalyses the breakdown of starch / makes maltose

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