IGCSE Biology Paper-4: Specimen Questions with Answers 125 - 126 of 279

Question 125

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Short Answer▾

Lack of protein in the diet can result in protein-energy malnutrition.

State the name of one disease caused by protein-energy malnutrition.

Explanation

Difference between Kwashiorkor and Marasmus

Passage

Plants produce glucose in leaves and convert some of it to sucrose.

Question 126 (1 of 7 Based on Passage)

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Short Answer▾

The movement of sucrose in plants can be modelled using laboratory apparatus.

Fig. shows the apparatus used to model the movement of sucrose in a plant:

  • Partially permeable bags were attached tightly to the ends of tube X.
  • The bag representing a source was filled with a colored sucrose solution.

  • The bag representing a sink was filled with water.

  • The containers and tube X and tube Z were filled with water.

Movement of Sucrose Solution

Fig. shows the position of the colored sucrose solution 45 minutes after the apparatus was set up.

The arrows show the direction of the movement of the liquids.

Sucrose Solution

(i) State the name of the tissue represented by tube X and the name of the tissue represented by tube Z in Fig.

X. . . . . . . . . . .

Z. . . . . . . . . . . .

Explanation

X – the movement of sugars in the phloem begins at the source, where sugars are loaded (actively transported) into a sieve tube. Loading of the phloem sets up a water potential gradient that facilitates the mass movement in the phloem.

Z – Xylem, water in the adjacent xylem moves into the phloem by osmosis.