1.1. A student investigated the effect of sugar solution concentration on the mass of potato cylinders. They cut potato cylinders to the same length and diameter and placed one cylinder into each of three different concentrations of sugar solution for 24 hours. Table 1 shows the results.

Table 1

(i) Calculate the percentage change in mass for the potato cylinder in the 0.4 mol/dm³ solution.

[2]

(ii) The potato cylinder in the 0.0 mol/dm³ solution increased in mass.

Explain why.

[2]

1.2. In another experiment a student added a drop of food colouring to two beakers of still water.

• Beaker A contained water at 20 °C

• Beaker B contained water at 40 °C

Explain why the food colouring spread throughout the water more quickly in Beaker B.

1.3. Glucose is absorbed in the small intestine.

Table 2 shows the concentration of glucose in the gut and in the blood at two points after eating a meal.

Table 2

Use the data in Table 2 to explain which transport method is used to absorb glucose into the blood at each point in time.

1.4. The small intestine is an example of an exchange surface.

Explain why large multicellular organisms need specialised exchange surfaces.