MODUL 2

LATIH TUBIBIOLOGI SPM

MODUL 2

TOPIC: MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANESECTION A: OBJECTIVE QUESTIONSAnswer all the questions1.The plasma membrane consists of molecules arranged in a double layer as

shown in the diagram below.

The part labelled I and II are

Ahydrophobic and hydrophilic respectively

Bhydrophilic and hydrophobic respectively

Cboth hydrophobic

Dboth hydrophilic

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

Which of the following is correct?PQR

APhospholipidCarbohydrate Protein

BProteinCholesterolPhospholipid

CPhospholipidCarbohydrateCholesterol

DPhospholipidProteinCarbohydrate

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?

PQR

AAmino acidGlucoseWater

BOxygenIonGlucose

CGlucoseAmino acidOxygen

DSmall proteinAmino acidCarbon 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?

AOsmosis

BActive transport

CSimple diffusion

DFacilitated diffusion

5. Molecules that can move easily through the plasma membrane by simple

diffusion include

IwaterIIoxygen

IIIcarbon dioxide

IVfat-soluble vitamins

AI and II only

BII and IV only

CI, II and III only

DI, 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

Aosmosis

Bsimple diffusion

Cactive transport

Dfacilitated diffusion

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

What are X and Y?

XY

ADistilled water20% sucrose solution

B20% sucrose solutionDistilled water

C20% sucrose solution20% sucrose solution

DDistilled waterDistilled water

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

AOsmosisActive transport

BOsmosisFacilitated diffusion

CFacilitated diffusionOsmosis

DActive transportOsmosis

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?

A1.5 g per 100 ml

B2.5 g per 100 ml

C3.5 g per 100 ml

D4.5 g per 100 ml

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

Which of the processes K, L and M involves diffusion?

AK only

BK and M only

CL and M only

DK, L and M11.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?

AThe cucumber cell wall prevents it from shrinking

BThe cell sap is hypotonic towards the sucrose solution

CThe high concentration of the cell sap in the vacuole causes water to

diffuse in

DThe 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?

AThe rate of water molecules exiting the cell is higher than entering the

cell

BThe rate of water molecules entering the cell is higher than exiting the cell

CNo water molecules are entering or exiting the cell

DThe 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.

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

Solution WSolution X

AIsotonic Hypotonic

BHypertonicHypotonic

CHypertonicHypertonic

DHypotonicIsotonic

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

Which of the following is matched correctly?

Process that takes place

AOsmosis

BDiffusion

CFacilitated diffusion

DActive transport

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?

AThe salt solution has diffused into the egg

BOsmosis occurred and the salt solution moved into the egg

COsmosis occurred and the water in the egg moved out of the egg

DWater 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 because

IThe pH of the solution is low

IIThe bacteria that cause food spoilage loses water to the surroundings

IIIThe dehydrated condition of the fruit inhibits the grouth of bacteria

IVThe high concentration of vinegar in the pickles is not conducive to the

growth of bacteria

AI, II and III only

BI, III and IV only

CII, III and IV only

DI, II, III and IV

17.A plasmolysed cell can revert to its normal condition by being

AImmersed in pure water

BImmersed in a concentrated salt solution

CImmersed in 10% sugar solution

DTaken 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.

Which of the following statement are true about the uptake of ions by the algae?

IThe absorption of ions is by active transport

IIThe absorption of ions is against the concentration gradient

IIIThe absorption of ions requires energy

IVThe amount of ions absorbed depends on the requirements of the algae.

AI and III only

BII and IV only

CI, II and III only

DI, II, III and IV

19.Which of the following processes is affected by the presence of a metabolic poison?

AAbsorption of water by root hairs

BUptake of iodine by algae living in the sea

CAbsorption of digested food in the small intestine

DThe movement of amino acids across the plasma membrane

20. Preservation of the food by eliminating water from the food involves

Aosmosis

Bsimple diffusion

Cactive transport

Dfacilitated diffusion

SECTION B: STRUCTURED QUESTIONS1.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(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.

[1 mark]

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

[2 marks]

(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).

[2 marks]

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]

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

StructureParticleHow the molecule moves across the structure

Q

R

S

[3 marks](d)Explain how the particle you suggested in (c) moves across S.

[4 marks]

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

[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(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 Benedicts solution?

[1 mark]

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

..

[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.

[2 marks]

SECTION C: ESSAY QUESTION1(a)A student made the following observation.

Explain the students 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 which

Have 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]

K The absorption of digested materials in the

intestine wall

L The intake of calcium ion by freshwater weeds

M The intake of oxygen by Ameoba

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

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