Form 4 BiologyChapter 3 Movement of Substances Across the Plasma Membrane

Objective Questions

1 Figure 1(a) shows a plant cell at the start of the experiment and Figure 1(b) shows the cell after it was immersed in a concentrated sugar solution.

(a) (b)Figure 1

Which of the following fills up the cell area labelled X?A WaterB AirC Sugar solutionD Cell sap

2 Which of the following processes can occur in the hair root cell when oxygen cannot be obtained by the cell?A Active transport onlyB Diffusion onlyC Transport and osmosisD Diffusion and osmosis

3 Plants obtain mineral ions from the soil. Which of the following is the plant’s intake method for the mineral ions?A DiffusionB OsmosisC AbsorptionD Active transportation

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4 Figure 2 shows the apparatus set-up that was prepared for an experiment. The solution in beaker X and beaker Y are tested for starch and reducing sugar, at the beginning of the experiment and after 30 minutes.

Figure 2Table 1 shows the results obtained.

Type of test

Iodine test Benedict test

Beaker X

Beginning of the experiment Negative Negative

After 30 minutes Negative Negative

Beaker Y

Beginning of the experiment Negative Negative

After 30 minutes Negative Positive

Table 1Which of the following about the experiment is not true?A The reducing sugar molecules can move through the Visking tubeB The saliva has changed the starch into reducing sugarC Dialysis occurs in both the beakersD The Visking tube is a partially permeable membrane

5 In the experiment that is shown in Figure 4, the solution level in the capillary tube rises and a white precipitate is formed. This is caused by process X and process Y respectively.

Figure 3

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State process X and process Y.Process X Process Y

A Diffusion OsmosisB Osmosis DiffusionC Active transport DiffusionD Active transport Osmosis

6 What is meant by active transport?A The movement of molecules from an area of high concentration to an area of low

concentration by using energyB The movement of molecules from an area of low concentration to an area of high

concentration by using energyC The movement of mineral ions from the water in the soil to the hair root cell by using

energyD The movement of glucose form the ileum lumen into the villus blood capillaries by

using energy

7 Figure 4 shows a water filled sac that is made of partially permeable materials and a boiling tube that is filled with sugar solution.

Figure 4

At the beginning of the experiment, the water filled sac and the boiling tube that is filled with sugar solution is weighed separately. Then, the sac is put into the boiling tube. After 30 minutes, the sac is removed from the boiling tube and both are weighed again. Which of the following results is the most likely to be obtained?

Mass of the sac Mass of the boiling tube and contentsA Decreases Decreases B Decreases IncreasesC Decreases No changeD Increases Decreases

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8 Figure 5 shows a plant cell after it is put into a type of solution.

Figure 5

What is the conclusion that can be made about the cell?A The plant cell is turgidB The plant cell sap is hypertonicC The plant cell sap loses mineral ions through osmosisD The plant cell sap has a lower osmotic pressure

9 Which of the following processes does not involve active transport?A The elimination of sodium chloride salt through the gills of a sea fishB The absorption of sodium ions from the uriniferous tubule into the blood capillaryC The absorption of water from the uriniferous tubule into the blood capillaryD The absorption of mineral salts by the plant hair roots

10 Figure 6 shows four mustard stem cuttings that are immersed respectively into solutions R, S, T and U, which have different osmotic concentrations, for 30 minutes.

Figure 6Which of the following arrangements shows an increasing order in the solutions’ osmotic pressure compared with the mustard stem cell sap?A R, S, T, UB U, R, T, S

C S, T, R, UD S, U, R, T

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Structure Question

The graph in Figure 1 shows the percentage of red blood cells that burst at different slat solution concentrations.

Figure 1

According to the graph above, answer the following questions.(a) (i) What is the percentage of salt solution concentration when the number of red blood

cells that burst is the same as the number of red blood cells that do not burst? (ii) Why doesn’t the red blood cell burst at a salt solution concentration of 0.48g/100 cm3? (iii) State two methods that the body uses to maintain the blood concentration so that it is

not more dilute than 0.48 g/ 100 cm3.(b) Explain why the red blood cells burst at a salt solution concentration that is lower than

0.48 g/ 100 cm3.(c) If the onion cells are immersed in distilled water, the cells do not burst. Why?(d) Explain why a plant will wilt and die if it is supplied with too much fertiliser.

Essay Question

(a) Explain why(i) the intake of a few types of mineral salts is stopped by the presence of oxygen or the

presence of respiration poison.(ii) when a small plant is transferred to a new place, it is better if some of its leaves is

thrown away. (b) Draw a cross-sectional diagram of a green leaf to show its cells. Label the structures that

are important for the leaf to carry out its function.

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Answers

Objective Questions1 C2 D3 D4 C5 B6 B7 B8 D9 C10 B

Structured Question(a) (i) 0.4 g/100 cm3

(ii) The solution is isotonic. The rate of water moving in and out of the cell is the same. As such, the red blood cell does not burst.

(iii) 1 Sweating2 Urinating a lot and urine is dilute

(b) The salt solution is hypotonic towards the liquid in the red blood cell. As such, the water enters the red blood cell by osmosis and causes the volume of the cytoplasm to increase. The plasma membrane is stretched beyond its elastic limit causing the red blood cell to burst.

(c) This is because the onion cell has a hard cell wall and can prevent excess water from entering.

(d) Excess fertilisers causes the soil solution to become a hypertonic solution compared with the hair root cell sap. The water moves out from the root hair cell by osmosis causing the plant cell to suffer from a lack of water until the enzyme in the cell can no longer function.

Essay Question(a) (i) The intake of mineral salts occurs through active transportation, which requires energy

from cell respiration. A condition with a lack of oxygen or the presence of respiration poison stops/slows down the rate of cell respiration to produce biological energy. When the plant is transferred to a new location, part of its main root system is cut off/injured. As such, the rate of water absorption from the soil by the small plant decreases. Cutting parts of the leaf helps to reduce the loss of water through transpiration.

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(b)

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