LATIH TUBIBIOLOGI SPM

JABATAN PELAJARAN KEDAH

MODUL 2TOPIC: MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE

SECTION A: OBJECTIVE QUESTIONSAnswer all the questions

1. The plasma membrane consists of molecules arranged in a double layer as shown in the diagram below.

The part labelled I and II areA hydrophobic and hydrophilic respectivelyB hydrophilic and hydrophobic respectivelyC both hydrophobic D both hydrophilic

2. The diagram below shows the detailed structure of the plasma membrane of an animal cell.

Which of the following is correct?

P Q RA Phospholipid Carbohydrate ProteinB Protein Cholesterol PhospholipidC Phospholipid Carbohydrate CholesterolD Phospholipid Protein Carbohydrate

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3. The diagram below shows three substances P, Q and R passing through the plasma membrane of a cell.

What substances are P, Q and R likely to be?

P Q RA Amino acid Glucose WaterB Oxygen Ion GlucoseC Glucose Amino acid OxygenD Small protein Amino acid Carbon dioxide

4. The diagram below shows the net flow of water molecules from a dilute solution to a concentrated solution through a semi-permeable membrane.

What is this process called?A OsmosisB Active transportC Simple diffusionD Facilitated diffusion

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5. Molecules that can move easily through the plasma membrane by simple diffusion includeI waterII oxygenIII carbon dioxideIV fat-soluble vitaminsA I and II onlyB II and IV onlyC I, II and III onlyD I, II, III and IV only

6. The diagram below shows a root cell with root hair.

The nitrate ion concentration is higher inside the cell and lower outside the cell and yet nitrate ions can enter the cell. The ions enter the cell by

A osmosisB simple diffusionC active transportD facilitated diffusion

7. The diagram below shows diffusion through a semi-permeable membrane.

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What are X and Y?

X YA Distilled water 20% sucrose solutionB 20% sucrose solution Distilled waterC 20% sucrose solution 20% sucrose solutionD Distilled water Distilled water

8. What are the processes involved in the movement of water and mineral ions into root hairs?

X YA Osmosis Active transportB Osmosis Facilitated diffusionC Facilitated diffusion OsmosisD Active transport Osmosis

9. The graph shows the changes in mass of potato strips immersed in different concentrations of sucrose solution.

Based on the above graph, which of the following concentrations of sucrose solution should be used so that a flaccid potato strip regains its turgidity?A 1.5 g per 100 mlB 2.5 g per 100 mlC 3.5 g per 100 mlD 4.5 g per 100 ml

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10. The following information shows some processes involving the movement of substances in cells.

Which of the processes K, L and M involves diffusion?A K onlyB K and M onlyC L and M onlyD K, L and M

11. Cucumber slices are immersed in 0.1% sucrose solution. After 3 hours, the slices are found to be turgid and hard.Which of the following statements explains this phenomenon?A The cucumber cell wall prevents it from shrinkingB The cell sap is hypotonic towards the sucrose solutionC The high concentration of the cell sap in the vacuole causes water to

diffuse inD The cucumber cell wall allows the sucrose molecules to diffuse into the

cell

12. A plant cell immersed in distilled water. Which of the following is true about the movement of water molecules in the early stage?A The rate of water molecules exiting the cell is higher than entering the

cell B The rate of water molecules entering the cell is higher than exiting the cell

C No water molecules are entering or exiting the cellD The rate of water molecules entering and exiting the cell is the same

13. The diagram below shows two types of cells that were seen under the microscope after being placed in solution W and solution X respectively for 15 minutes.

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K – The absorption of digested materials in the intestine wallL – The intake of calcium ion by freshwater weeds

M – The intake of oxygen by Ameoba

Which of the following show the osmotic concentration of solution W and solution X compared with the initial osmotic concentration of each cell?

Solution W Solution XA Isotonic HypotonicB Hypertonic HypotonicC Hypertonic HypertonicD Hypotonic Isotonic

14. The diagram below shows processes that occur in various tissues and cells.

Which of the following is matched correctly?

Process that takes placeA OsmosisB DiffusionC Facilitated diffusionD Active transport

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15. The diagram below shows an egg being immersed in a saturated salt solution.

After a week, the egg tasted salty when cooked. What has happened?A The salt solution has diffused into the eggB Osmosis occurred and the salt solution moved into the eggC Osmosis occurred and the water in the egg moved out of the eggD Water has moved into the egg

16. Siti is going to prepare some mango pickle. First, she cuts and washed the mangoes. Then she adds vinegar and sugar to the mangoes. After one month, the mango pickle remains in good edible condition becauseI The pH of the solution is low II The bacteria that cause food spoilage loses water to the surroundingsIII The dehydrated condition of the fruit inhibits the grouth of bacteriaIV The high concentration of vinegar in the pickles is not conducive to the

growth of bacteriaA I, II and III onlyB I, III and IV onlyC II, III and IV onlyD I, II, III and IV

17. A plasmolysed cell can revert to its normal condition by beingA Immersed in pure waterB Immersed in a concentrated salt solutionC Immersed in 10% sugar solutionD Taken out quickly from the solution

18. The diagram below shows a comparison of ion concentrations in the cell sap of algae and in the pond water.

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Which of the following statement are true about the uptake of ions by the algae?I The absorption of ions is by active transportII The absorption of ions is against the concentration gradientIII The absorption of ions requires energyIV The amount of ions absorbed depends on the requirements of the algae.A I and III onlyB II and IV onlyC I, II and III onlyD I, II, III and IV

19. Which of the following processes is affected by the presence of a metabolic poison?A Absorption of water by root hairsB Uptake of iodine by algae living in the seaC Absorption of digested food in the small intestineD The movement of amino acids across the plasma membrane

20. Preservation of the food by eliminating water from the food involvesA osmosisB simple diffusionC active transportD facilitated diffusion

SECTION B: STRUCTURED QUESTIONS

1. A student carries out an experiment by using five potato cylinders of the same length and diameter. Each potato cylinder is wiped dry with tissue paper and weighed to obtain its initial mass. The potato is then immersed in five beakers, each with different concentration of sucrose solution. After one hour, the potato cylinders are wiped dry and weighed again. The results are shown in Table 1.

Concentration of sucrose solution ( M)

Percentage of mass change (%)

0.1 6

0.2 2

0.3 -2

0.4 -6

0.5 -10

Table 1

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(a) Based on the information in Table 1, draw a graph of the percentage of mass change against the concentration of sucrose solution.

[3 marks]

(b)(i) Based on the graph that you have drawn, state the concentration of sucrose solution that does not cause a change in the mass of the potato.

……………………………………………………………………………………………………… [1 mark]

(ii) State the term that is used to explain the concentration of sucrose solution and the concentration of the potato cell sap in (b)(i).

………………………………………………………………………………………………………[1 mark]

(c) What is the probable percentage of mass change of the potato if it is immersed in distilled water?

………………………………………………………………………………………………………[1 mark]

(d)(i) State the process that causes the change in mass of the potato when it is immersed in 0.5 M sucrose solution.

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(ii) Explain your answer in (d)(i).

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(e)(i) What is the change that can be felt by hand for the potato cylinder that is placed in 0.1 M sucrose solution?

………………………………………………………………………………………………………[1 mark]

(ii) Explain your answer in (e)(i).

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2. Diagram 1 shows the fluid-mosaic model of a plasma membrane.

Diagram 1

(a) Label the structures P, Q, R and S.

P:……………………………………..

Q: ……………………………………

R: …………………………………….

S: ……………………………………. [2 marks]

(b) The plasma membrane is said to be semi-permeable. What is the meaning of ‘semi-permeable’?

………………………………………………………………………………………………………

………………………………………………………………………………………………………[1 mark]

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(c) State one example of a particle and describe how the particle moves across each of the following structures.

Structure Particle How the molecule moves across the structure

QRS

[3 marks]

(d) Explain how the particle you suggested in (c) moves across S.

………………………………………………………………………………………………………

………………………………………………………………………………………………………

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………………………………………………………………………………………………………[4 marks]

(e) Describe the principle of food preservation based on the mechanism of movement of substances across the plasma membrane.

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………………………………………………………………………………………………………[3 marks]

3. Diagram 2 shows an experiment to investigate the semi-permeablility of Visking tubing. A Visking tubing filled with solution X is placed in a beaker of distilled water containing iodine solution for 30 minutes.

Diagram 2

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(a) What is solution X?

……………………………………………………………………………………………………… [1 mark]]

(b) Why did solution X turn from colourless to be blue-black.

………………………………………………………………………………………………………

……………………………………………………………………………………………………… [2 marks]

(c)(i) What will be observed when the distilled water is tested with Benedict’s solution?

……………………………………………………………………………………………………… [1 mark]

(ii) Explain your answer in (c)(i).

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…………………………………………………………………………………………………….. [2 mark]

(d) At the end of the experiment, the student noticed a change in the condition of the Visking tubing.

(i) What did the student observe?

……………………………………………………………………………………………………… [1 mark]

(ii) Explain what caused this change.

………………………………………………………………………………………………………

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……………………………………………………………………………………………………… [2 marks]

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SECTION C: ESSAY QUESTION

1(a) A student made the following observation.

Explain the student’s observation. [5 marks]

(b) Some housewives believe soaking vegetables in salt solution before cooking can help eliminate the harmful effects of insecticides that are sprayed on the vegetables.

(i) Explain why vegetables become soft if they are soaked too long in salt solution.

(ii) Suggest how the housewives can restore the vegetables whichHave become floppy to their normal condition. [5 marks]

(c) Describe in detail how(i) Amino acid, and(ii) Sodium ions can be tranported across the plasma membrane.

[10 marks]

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The effects of distilled water on red blood cells differ from those on onion cells when both are placed in equal volumes of distilled water

MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE

SECTION A:Objective Question:

1 B2 D3 B4 A5 D6 C7 B8 D9 B10 B11 C12 B13 C14 C15 A16 D17 A18 D19 B20 A

SECTION B: Structured questions

1(a)

(b) (i) 0.25 M(ii) Isotonic

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(c) More than 6%(d) (i) Plasmolysis

(ii) 0.5 M sucrose solution is hypertonic compared to the cell sap of a potato. Due to this, the water molecules from the potato cell diffuse out by osmosis.

(e)(i) turgid (ii) 0.1 M sucrose solution is hypotonic compared with the cell sap of a potato. Due to this, the water molecules diffuse into the potato cell and cause it to

become turgid.

2. (a) P: hydrophilic head Q: hydrophobic tail R: pore protein S: carrier protein

(b) A semi-permeable plasma membrane allows only certain substances to move freely across it while others cannot do so.

(c)

Structure Molecule How the molecule moves across

Q Lipid-soluble molecule such as glycerol

Simple diffusion

R Ion Facilitated diffusion

S Glucose Facilitated diffusion

(d) -The glucose molecule moves towards the binding site of the specific carrier protein-The molecule binds to a specific site on the carrier protein-The carrier protein changes its shape to transport the molecule across the plasma membrane-The carrier protein assumes its original shape and is free to assist the passage of other glucose molecules into the cell.

(e) -The addition of preservatives such as concentrated sugar solution makes the

surrounding solution hypertonic.-The hypertonic solution causes water to leave the food by osmosis and the preservatives to enter the food.-The dehydrated condition of the food as well the presence of preservatives prevent the grouth of bacteria and fungi.

3 (a) Mixture of starch suspension and glucose solution (b) Iodine molecules diffuse into the Visking tubing and react with the starch in solution X to give a blue black colour.

(c) (i) A brick-red precipitate is formed(ii) The brick-red precipitated shows that glucose molecules are present in the beaker. The glucose molecules are small enough to diffuse through the

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membrane of the Visking tubing to the surrounding distilled water. (d) (i) The Visking tubing swells and become firm. (ii) Since the concentration of solution X inside the Visking tubing is higher, water enters the Visking tubing by osmosis and caused the tubing to swell and become firm.

SECTION C:Essay question

1(a)- Distilled water is hypotonic to the cytoplasm of red blood cells and the cell sap of the onion cells.(1m)

- Osmosis occurs, resulting in a net flow of water from the surrounding into the cell.(1m) - The red blood cells will swell and eventually burst (1m) - The vacuoles in the onion cells expand, and the plant cells become turgid (1m) - However, the cell wall prevents the onion cells from bursting because it is tough and rigid (1m) ----- 5m -----

(b)(i) -Vegetables which are soaked too long in a salt solution will become soft because the salt solution is more hypertonic than the cytoplasm of the vegetable cells (1m) -Water flow out of the cells, causing the cytoplasm and the vacuoles to shrink (1m). -The plasma membranes pull away from the cell walls (1m) -In this condition, the cells are said to be plasmolysed (1m) (ii) To make the vegetables crisp again, housewives can soak the vegetables in water (1m)

------ 5m ------

(c) (i) Transport of amino acids across the plasma membrane: -Amino acids move across the plasma membrane through facilitated diffusion.(1m)

-Amino acids are transported from a region of higher concentration to a region of lower concentration with the help of carrier proteins(1m) -One of the amino acids moves towards the active site of a specific carrier protein and binds to it (1m) -The carrier protein changes its shape to transport the amino acids across the plasma membrane (1m). -The carrier protein assumes its original shape and is free to assist the passage of other amino acids molecules into the cell (1m) ------ 5m ------

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(ii) Transport of sodium ions across the plasma membrane : -The transport of sodium ions across the plasma membrane is by meant of active transport (1m) -The concentration of sodium ions is higher outside the cell. Sodium ions are transported against a concentration gradient, from a region of lower concentration to a region of higher concentration (1m) -In active transport, sodium ions approach the carrier protein. Each carrier protein has a site for binding of three sodium ions at one time and another site for ATP (1m) -The ATP molecules is split into ADP (Adenosine diphosphate) and P (phosphate). The phosphate group (P) attaches itself to the carrier protein. The spliting of ATP releases energy to the carrier protein (1m) -Energy from the ATP changes the shape of the carrier protein and this causes the carrier protein to release the three sodium ions ooutside the cell (1m). ------ 5m ------

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