Section A[60 marks]

Answer all questions in this section

1. Diagram 1.1 shows a typical animal cell and a typical plant cell as seen under the light

microscope.

Diagram 1.1

(a) (i) Name the structure P and Q.

P: ……………………………………………………………………………

Q: ……………………………………………………………………………

[2 marks]

(ii) Table 1.1 shows some structures in the cells.

Cell Wall

Cytoplasm

Nucleus

Chloroplast

Plasma membrane

TABLE 1.1

Tick ( √ ) the non-organelles that are found in both plant and animal cells in Table 1.1.

[2 marks]

(b) The plasma membrane regulates the movement of substances in and out of the cell.

(i) State one characteristic of molecules that can pass through channel protein

……………………………………………………………………………………...

[1 mark]

1

(ii) Explain how these molecules pass through the channel protein.

……….……………………………………………………………………………..

...............……………………………………………………………………..........

……..……………………………………………………………………………….

[2 marks]

(c) Diagram 1.2 shows the cell organisation in a multicellular organism. Name M

and N in the spaces provided in Diagram 1.2.

Epithelial cell

M:

Diagram 1.2[2 marks]

(d)

(i) Name two types of tissues in the skin.

………………………………………………………………………………………….

…………………………………………………………………………………………..

[2 marks]

(ii) State the function of each tissue named in (d)(i).

…………………………………………………………………………………………..

…………………………………………………………………………………………..

…………………………………………………………………………………………..

…………………………………………………………………………………………..

[2 marks]

2

Digestive System N:Human

Human skin is an organ. It consists of various types of tissues that

perform specific functions collectively.

2. Diagram 2.1 shows two strips of mustard green stem after 20 minutes immersed into

two different solutions P and Q.

Diagram 2.1

(a) Based on the Diagram 2.1

(i) State the type of solution Q.

.................................................................................................................................

.

[1 mark]

(ii) Explain how the solution Q affects the condition of the cells in the strip that have

been immersed. .

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

[2 marks]

(iii) If strip from the solution Q is transferred into solution P, explain what will happen

to the cells in the strip after 20 minutes.

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………..…….

3

PDistilled water

Epidermal layer

Q30% sucrose solution

Epidermal layer

[3 marks]

(b) Diagram 2.2 shows the red blood cells in different concentrations of solutions.

.

Diagram 2.2

Explain the differences between the process experienced by the red blood cell X and

Y after being immersed for half an hour.

……………………………………………………………………………………………

……………………………………………………………………………………………

…………………………………………………………………………………………….

……………………………………………………………………………………………

[3 marks]

(c) Vinegar is natural preservative that can be used to preserve fruits and vegetables to

last longer. Explain how the preservative is effective in the preservation of mangoes.

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

.......................................................................................................................................

[3marks]

4

Red blood cells X in 3% sodium chloride solution after 30 minutes

Red blood cells Y in 0.1% sodium chloride solution after 30 minutes

3. Diagram 3.1 shows the structure of a plasma membrane.

Diagram 3.1

(a) Plasma membrane is a semi permeable membrane and has a fluidity characteristic.

(i) State the meaning of semi-permeable membrane.

………………………………………………………………..……..…………………….

…………………………………………………………………………………………….

[1 mark]

(ii) Explain the cause that makes the plasma membrane has the fluidity

characteristic.

……………………………………………………………………………………………..

………………………………………………………………………………………….….

………………………………………………………………………………………..……

[2 marks]

5

Molecule P

XMolecule Q

(b) Molecule P move across the plasma membrane follow the concentration gradient

whereas molecule Q move across structure X against the concentration gradient.

(i) Name two examples of molecule P.

………………………………………………………………………………………….….

[1 mark]

(ii) Explain how molecules Q move across structure X.

……………………………………………………………………………….…………….

……………………………………………………………………………………….…….

……………………………………………………………………………………….…….

……………………………………………………………………………………….…….

[3 marks]

(c) Diagram 3.2 shows the effect of solution X on human blood cells.

50 ml of solution X was added into 10 ml of human blood and left for 45 minutes.

10 ml blood

50 ml solution X

red sediment

Diagram 3.2

Diagram 3.3 shows the effect of solution Y on human blood cells.

50 ml of solution Y was added into 10 ml of human blood and left for 45 minutes.

6

After 45 minuteswithout stir it.

Clear solution

50 ml solution Y

10 ml blood

Diagram 3.3

(i) Use a tick (√) in the correct column to identify solution X and Y

Name of the solution Distilled Water 10% Salt solution

Solution X

Solution Y

[1 mark]

(ii) Explain the effect of solution Y on human blood cells as shown in Diagram 3.3.

…………………………………………………………………………………………………

…………………………………………………………………………………………………

……………………………………………………………………………………………….

…………………………………………………………………………………………………

…………………………………………………………………………………………………

[4 marks]

7

After 45 minuteswithout stir it.

Clear red solution

4. Diagram 4.1 shows the four levels of structural organization in protein structures

Diagram 4.1

(a) Based on the diagram 4.1, name the level of structural organisation for each protein molecule in level 1, 2, 3 and 4

Level 1:…………………………………….. Level 2: ………………………….

Level 3 : …………………………………… Level 4: ………………………….

[4 marks]

(b) (i) Explain the chemical process which forms the molecule in level 1 from its basic unit.

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

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

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

8

Level 1

Level 4

Level 3

Level 2

Amino acids

Alpha helix

Alpha helix

Pleated sheet

Pleated sheet

(ii) Name the chemical process which breakdown macromolecule of protein into small molecules.

…………………………………………………………………………………………………..

[1 mark](c) Diagram 4.2 shows the involvement of various organelles in an animal cell during

the synthesis extra cellular enzymes

Diagram 4.2

(i) State the function of organelles labeled W, X, Y and Z.

W : …………………………………………………………………………………………

X : …………………………………………………………………………………………

Y : ………………………………………………………………………………………….

Z : ………………………………………………………………………………………….[2 marks]

(i) Predict what will happen to the synthesis of extra cellular enzymes if organelle X is absent

……………………………………………………………………………………………........

…………………………………………………………………………………………………

………………………………………………………………………………………………

…………………………………………………………………………………………………

[3 marks]

9

X

5 The figure bellows shows the structure of a lipid molecule.

(a) Name the parts X and Y.

X :…………………………………….

Y : ……………………………………..[2 marks]

(b) (i) What is the chemical reaction P that takes place to form the bonds between X and Y?

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

(ii) What is product Q which form during this reaction?

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

(c) (i) What is the structural difference between a phospholipid molecule and the lipid molecule shown in the figure above?

………………………………………………………………………………………………

……………………………………………………………………………………………..

[2 marks](ii) What is the function of phospholipids in cells?

………………………………………………………………………………………………

…………………………………………………………………………………………….

[2 marks]

(d) Name two types of steroid compounds found in humans.

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

(e) State two differences between saturated fats and unsaturated fats.

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

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

10

[2 marks]

Section B[40 marks]

Answer any two questions from this section

6. (a) Diagram 6.1 shows the initial and final stage of an experiment.

Explain the result of the experiment.

[4 marks]

(b) Diagram 6.2 shows the changes of a plant cells when immersed in two different concentration of sucrose solution P and Q for 30 minutes one after another.

Diagram 6.2

Explain the observation made on the plant cell.

11

X Y X Y

Initial stage of experiment

Final stage of the experiment

10% sucrosesolution

5% sucrose solution

Sucrose solution P

Sucrose solution Q

Diagram 6.1

[8 marks](c) Diagram 6.3 shows the structure of a plasma membrane and the concentration of

different molecules inside and outside of a cell

Diagram 6.3

Rajah 6.3

Diagram 6.3

Based on Diagram 6.3 describe the movement of molecules across the plasma membrane into the cell.

[8 marks]

7. (a)

Based on the statement:

(i) list the general characteristic of enzymes .[4 marks]

(ii) Using suitable examples, discuss the uses of enzymes in industrial processes and our daily life.

[6 marks]

8. (a) Draw and label an animal cell. [4 marks]

(b) State the function of four organelles in the animal cell that you have drawn. [8 marks]

12

Potassium ion

Water molecule

Vitamin E

Outside cell

Inside cell

Enzymes which are isolated from cells can function outside the cells. Enzymes can be used as catalysts in industries. The use of enzymes in industrial processes is known as enzyme technology.

(c) Compare and contrast between a plant cell with an animal cell.[8 marks]

9. A student made the following observation.

(a) Explain what happen to the red blood cell in these three different concentration of sodium chloride solution.

[14 marks]

(b) State three differences between passive transport and active transport. [6 marks]

END OF QUESTION PAPER

13

FIGURE 7(b) Figure 7 shows the organelles involved during the synthesis and secretion of an

enzyme in an animal cell.Based on Figure 6, explain how extracellular enzyme are produced by emphasizing on the role of P, Q, R and S.

[10 Marks]

14

BIOLOGY FORM CHAPTER 4: CHEMICAL SUBSTANCE IN CELL

Diagram 1.1 shows the organelles involved in the synthesis and secretion of an extracellular enzyme in an animal cell.Rajah 1.1 menunjukkan organel-organel yang terlibat dalam sintesis dan rembesan enzim luar sel di dalam sel haiwan.

Diagram 1.1/ Rajah 1.1

(a) Based on Diagram 1.1, explain the processes involved in the production of extracellular enzymes.

[6 marks]

(b) Diagram 1.2 shows two types of complex molecules.

15

Diagram 1.2 Based on Diagram 1.2, explain

(i) the formation of molecules X

(ii) the breakdown of molecule Y [4 marks]

(c) Starch, protein and lipid can be hydrolysed by the enzymes X, Y and Z respectively.Diagram 1.3 is a graph which shows the effect of pH on the rate of enzyme activity.

Diagram 1.3

(c) Based on the Diagram 1.3, name X, Y and Z and explain how the changes in pH affects enzyme activity.

[10 marks]

16

(b) Diagram 2.1 shows the involvement of different cellular component P, Q, R and S in the secretion of extracellular enzymes in animal cell. Rajah 2.1 menunjukkan penglibatan komponen sel yang berbeza P, Q, R dan S di dalam perembesan enzim luar sel dalam sel haiwan.

Diagram 2.1Rajah 2.1

Based on the Diagram 2.1, describe the production of extracellular enzymes.Berdasarkan Rajah 2.1, huraikan proses penghasilan enzim luar sel.

[6 marks][6 markah]

No Marking criteria Mark Total

1(a)

(b)

QUESTION 1Able to name the cell in Figure 1.1P: Guard cellsQ: Smooth muscle / muscle cellR: Efferent neuron / nerve cell/ neuron

Able to state the function of P, Q and R

Function of P: Regulate size of stoma. Function of Q: Contraction of Q causes movement of substances.Function of R: transmission of impulses (from CNS to effector)

111

1

11

3

3

17

(c)

(d)

Able to complete the cell organization M and N in the spaces provided in Figure 1.2.

M: epithelial tissueN: small intestine / stomach

Able to name two types of tissues

Sample answer:

Epithelial tissue// connective tissue// muscular tissue// nerves

tissue.

Any two tissues

Able to state the function of each tissue named in (d)(i)

Sample answer:

i. Epithelial tissue

Function: as a protective layer/ excretion/heat regulation

ii. Connective tissue

Function: such as blood, supplies oxygen and nutrients.

iii. Muscle tissue

Function: regulate body temperature

iv. Nerve tissue

Function: receive and send impulses from and to the central

nervous system.

( Any two types and functions)

TOTAL MARKS

f

11

1,1

1

1

1

1

2

2

2

12

No 2 Marking criteria Mark Total

(a)

(b)(i)

(ii)

Able to label P,Q R and S

P: Starch grain 3-4 correct= 2mQ: Stroma 2 correct = 1mR: Granum//Grana 1 correct = 0S: chloroplast envelopes // Outer membrane

Able to name the organelle in Diagram 1.1

Chloroplast

Able to explain the function of the organelle in a(ii)

2m

1m

2

1

18

(iii)

c.

d.i.

ii

iii

Contain chlorophyll which traps light energy and convert it chemical energy..

Able to name the process that occurs in Diagram 1.1

Photosynthesis

Able to write the word equation of the process in c(i)

Sunlight

Carbon dioxide + Water Chloroplast Glucose + Oxygen

Able to give one example of a cell that contains high density of the organelle above and explain the answer.

Palisade mesophyll cell.For maximum absorption of sunlight used in the photolysis of water.

X : PhospholipidY : Pore protein// Channel protein

Glucose// amino acid

P1 - Glucose binds to the carrier protein/PP2 - Carrier protein/P changes shape to allow the glucose to pass through

1m

1m

2m

1m2m

1m1m

1m

1m1m

1

3m

3m

Question 3 Marks(a) A : rough endoplasmic reticulum

B : nucleusC : mitochondrionD : Golgi apparatus

4√ = 3 marksReject: Wrong spelling 2-3 √ = 2 marks

1 √ = 0

3

(b) P1 – Chromosomes/DNA in organelle B (nucleus) determine the type of protein synthesized.P2 - Synthesis of polypeptide/protein occurs at ribosome on the surface of organelle A (RER). P3 - Transport vesicles carrying the polypeptide from organelle A fused with organelle D (Golgi Apparatus). P4 - These proteins are modified, sorted and packaged in organelle D.

1

11

1

19

P5 - Organelle E (Secretory vesicles) then bud off from organelle D and travel to the plasma membrane to be secreted.

Any 3

1Max 3

(c)(i)

P – Carrier proteinQ – Channel protein / Pore proteinS – PhospholipidsReject: wrong spelling

111

(ii)

2

(iii) Amino acid – Facilitated diffusionOxygen – Diffusion / simple diffusion

11

13 marks

Question 4

No Marking criteria (a)(i) Able to name cell P and tissuel R.

Answer :P : White blood cell / monocycte /leucocyteR : Phloem

1+1 2

(a)(ii) Able to state one function of cell P and tissue R.Sample answerP : to fight infections / engulf / digest bacteria / defence mechanism //carry out phagocytosisR : to transport organic food / sugar / sucrose / glucose from leaves to all parts of plant / example

1+1 2

(b)(i) Able to name the system which consists of cell S.AnswerNervous system

1 1

(b)(ii) Able to explain one role of cell S in the system.Sample answerF : control / coordinate activities of the bodyE1 : detect stimuliE2 : transmit electrical signals / nerve impulse

2 2

20

Amino acid oxygen

E3 : to muscle / gland / effector Any two

(c) Able to explain one characteristic of cell Q/root hair to facilitate water absorption from soil.Sample answerF1 : have large numberE1 : to provide large surface areaF2: (cells in tissue Q is ) one-cell thickE2 : to increase diffusion / osmosis rate.E2: have a higher concentration of solutes than the water in surrounding soil Any two

2 2

(d) Able to explain how herbicide is capable to stop the transportation of some mineral into a plant throughSample answerF : Herbicide contains active respiratory poison / toxicE1: denatures the respiratory enzymesE2. which stops cellular respirationE3 : no production of ATP.E4 . Active transport of the ions cannot take place in the absence of ATP Any three

3 3

TOTAL 12

Question Sample Answer M1 M2

1 (a) (i) Organelle X : Chloroplast 1(ii) Organelle Y : Mitochondrion 1 2

(b) P : - P is the stroma- Dark reaction takes place in the stroma- Carbon dioxide is fixed and then reduced to form glucose

Q :- Q is the granum- Light reaction takes place in the granum- granum trapped light energy to break down water molecule into hydrogen ion and hydroxyl ion.

R :- Cellular respiration takes place in R- glucose is oxidized by oxygen to produce energy.

111

111

11

max2

max2

2

(c) - process in organelle X absorb carbon dioxide and release oxygen- process in organelle Y absorb oxygen and release carbon dioxide

1111 4

21

- process in organelle X use energy to synthesis glucose- process in organelle Y break down glucose to produce energy

Total 12

No Mark SchemeSub mark

Total mark

6(a) (i) Able to name tissue L and tissue M.

L: XylemM: Phloem

11

2(ii) Able to state the function of tissue L and M in a leaf.

L: Xylem transports water and (dissolved) minerals (from the root to the shoot // provide mechanical support to the plants.

M: Phloem transport organic food/glucose/product of photosynthesis (from the leaves to every parts of the plant)

1

12

(b) Able to state the meaning of tissue and organ.

Tissue: (tissue are formed when) a group of similar cells that perform a specific function

Organ: (An organ consists of) a group of different tissues that (group together to) perform a specific function

1

12

(c) Able to explain the process of cell specialisation.

P1: The process where cells change shape/ structure and differentiateP2: To carry out / perform specific function

11

2(d) Able to explain two adaptation of the leaf to carry out

photosynthesis efficiently

F1: Leaf mosaic / leaves overlap each otherP1: To receive maximum amount of lightF2: Thin laminaP2: To receive maximum amount of lightF3: Flattened shape of laminaP3: Allow diffusion of gases for photosynthesisF4: Outer surface of a leaf / cuticle which is waxy / waterproofP4: Prevent water lossF5: Lower surface contain abundant of stomataP5: Allowing the exchange of gases between the internal part

of leaf and the environmentF6: Palisade mesophyll tissue are upright and closely packed

and contains large number of chloroplastP6: Absorb maximum amount of lightF7: Spongy mesophyll loosely arranged / contain air spacesP7: Easy diffusion of water and carbon dioxideF8: Irregular shapes of mesophyllP8: To increase the internal surface area for gaseous exchange

1111111111

1

11111

22

Any 2F and PMax:

4

Total 12

2.(a)(i)

(a)(ii)

(b)(i)

(ii)

(c)

QUESTION 1

Able to label the structure P and Q in the spaces provided in Figure 2.1.

Sample Answer:P: NucleusQ: Cytoplasm

Able to tick ( √ )the non organelles that are found in plant and animal cells in Table 2.1

Sample Answer:Plasma membrane and cytoplasm

Able to state the characteristics of the molecule that can pass through channel protein of plasma membrane.

Sample answer:

Small / water a soluble molecule / discharged particle/ion / dissolved gaseous.

Able to explain how molecules pass through channel protein

Sample answer

Small molecules / ions move through the protein pore in the channel protein by simple diffusion.

The molecules are at higher concentration (outside) diffuse into the cell cause the molecules to diffuse to a lower concentration into the cells through the pore/ down the concentration gradient.

Able to explain the plant cell shown in Figure 2.2 and 2.3 Sample answer: Figure 2.2 F1: the sucrose solution is hypertonic to the plant cell sap E1: water molecules diffuse out by osmosis E2 :the cell undergoes plasmolysis/ cytoplasm shrink.f F1 with E1 / E2

Figure 2.3 F2: the sucrose solution is hypotonic to the plant sap E3: water molecules diffuse in by osmosis E4: the plants become turgid F2 with E4 / E5

11

2

1

11

1

111

111

2

2

1

3

2

2

23

TOTAL MARKS

12

Question 2NUM SCORING CRITERIA MARKS2(a) Able to draw the shape of each strip after 20 minutes and label

the epidermis. Answer:

P=1R=1 2

2(a)(i) Able state the type of solution in beaker Q.Answer: hypertonic solution 1

2(a)(ii) Able to explain how the solution in the beaker Q affects the condition of the cells in the strip that have been immersed Suggested Answer:P1: 30% sucrose solution / solution in beaker Q is hypertonic

compare to the cell sapP2: water molecules diffuse out of the large central vacuole by

osmosis P3: both vacuole and cytoplasm shrink // the plasma membrane pulls

away from the rigid cell wall // the cells becomes flaccid, plasmolysis occurs.

Any 2

1

1

1Max 2

2(a)(iii)

2(b)

Able to describe what will happen to the cells in the strip if strip from the beaker Q is transferred into beaker PSuggested Answer:P1: distilled water / solution in beaker P is hypotonic compare to the

cell sapP2: water molecules diffuse into the large central vacuole /cell sap by

osmosis P3: central vacuole expand and swell up // plasma membrane pushes

against the rigid cell wall P4: flaccid cell becomes fully turgid again P5: the cells is said to have undergone deplasmolysis

Any 3

X undergoes crenation while Y hemolysisWater diffuse out from X while diffuse into Y by osmosisX immersed in hypertonic solution while Y in hypotonic solution

1

1

1

11

Max3

24

Q

Epidermis

P

Epidermis

2(c) Able to explain how the preservative is effective in the preservation of the fruitSuggested Answer:P1: Fruit / mangoes are immersed in vinegar which is has a low pH /

acidicP2: Vinegar diffuses into the tisues of the mangoes / fruit P3: The tissues of mangoes / fruits becomes acidicP4: The low pH prevent bacterial growth in the tissues / mangoes /

fruitsP5: This prevents decay of the fruits/mangoes // the mangoes / fruit

can be preserved to last longer Any 4

1

111

1

Total

Max 4

12

QUESTION 3(a) (i) - semi-permeable membrane is the membrane which only

permit some substances to move across it freely while other cannot.

1 1

(ii) - fluidity characteristics is caused by the protein molecules which are floating in the phospholipids bilayer.- the position of the molecules also keep on changing / not fixed in the position.

1

1 2

(b) (i) Fatty acids , glycerol , carbon dioxide, oxygen, water – any two 1 1(ii) - molecule Q bind with the binding site of structure X.

- ATP provides energy to structure X and cause structure X to change its shape.- structure X push / pump molecule Q across it.

11

1 3

(c) (i) Solution X : salt solutionSolution Y : distilled water - both correct 1 1

(ii) - distilled water is hypotonic compare to the cytoplasmic fluid in the red blood cells.- osmosis takes place- water molecules diffuse into red blood cell.- red blood cells swell and burst / haemolysis occur- cytoplasmic fluid of red blood cells cause the solution change into clear red

1

1111

max4

Total 12

25

QUESTION 4

No Mark SchemeSub mark

Total mark

4(a) (i) Able to name the cellular component.

AnswerPlasma // cell membrane 1

1(ii) Able to name P and Q

AnswerP: Phospholipid bilayerQ: Carrier Protein

11

2(b) (i) Able to draw arrow to show the movement of oxygen

across this cellular component during day time.

Answer Arrow from inside the cell outside the cell, pass through phospholipid bilayer

1 1

(ii) Able to explain the answer in (b)(i).

Sample answersE1: (During day time), photosynthesis occurs in the cell to

produce O2

E2: O2 diffuses from higher concentration region to lower concentration region // O2 diffuses by following the concentration gradient

E3: O2 is non-polar molecule / small moleculeE4: O2 diffuses through phospholipid bilayer

Any 3

11

11

3

(c) (i) Able to explain what will happen to the cellular component.

Sample answersF: This cellular component / plasma membrane is

pushed against the cell wallE1: Distilled water is hypotonic to the cell sap // Cell sap is

hypertonic to distilled waterE2: Water molecules diffuse into the cell by osmosisE3: vacoule expand/ swell up Any

3

1

1

11

3

(ii) Able to draw a labelled diagram of the condition of palisade mesophyll cell after being immersed in the distilled water.

Sample answer

26

D: The shape of the cell must be rectangularThe cell wall is drawn with double lineThe vacuole must be large

L: Label vacuole*Reject other shape of the cell

1

12

Num SCORING CRITERIA MARK1(a) Able to label S in Diagram 1

Answer: Glucose 11(b) Able to state two characteristics of the enzyme explained by

the hypothesisAnswer: P1 : Enzyme are highly specificP2 : Enzyme are not destroy at the end of reactionP3 : Enzyme catalysed reaction are reversible

111

Max 2

marks1(c)(i) Able to explain the reaction of sucrase if the temperature

meium is 600CSuggested Answer:P1 : 600C is high temperature P2 :At very high temperature the chemical bond that hold enzyme molecules together begin to breakP3 : thus altering the three dimensional shape of enzymeP4 : destroying active site of enzyme/enzyme denatured

11

11

Max 3

marks 1(c)(ii) Able to explain the reaction of sucrase if pH value medium is

3Suggested AnswerP1 : At low pH value excess hydrogen ions attach to the active site of enzymeP2 : Cause ionic charges on the active sites are alteredP3 : Substrate is unable to bind to the enzyme/ reaction cannot take place

1

11

Max 2 mark

1(d)(i) Able to explain examples of the applications of enzymes in dairy products industryAnswer:P1 : LipaseE1 : Ripening cheeseorP2 : RenninE2 : Solidify milk protein

11

11

Max2

marks

1(d)(ii) Able to explain examples of the applications of enzymes in

27

cereal grains products industryAnswer:P1 : CelluloseE1 : Breakdown cellulose and removes seed coat from cereal grains

11

Max2

marks

Total 12

marks

No Criteria, Sample answer Marks allocated

Remarks

1(a)

(b)(i)

(b)(ii)

(c)(i)

(d)

Able to state the structural organization of protein shown in level 1, 2, 3 and 4Sample answer:Level 1: primary structure Level 2: secondary structureLevel 3: tertiary structureLevel 4: Quaternary structure

Able to state the name of chemical process and explain the property/ies of the process

Sample answer:F: condensation P1: amino acids are link by peptide bondsP2: water molecules are released/liberated during the process

Sample answer:Hydrolysis

Able to state the function of each organelles shown in diagram 1.2Sample answer;W: secretes modified protein(by Golgi apparatus)/enzymes outside of cellX: modifying protein (produced by ribosome) /packaging modified protein into secretory vesiclesY: transport protein (produced by ribosome) to Golgi apparatus//packaging protein (produced by ribosome) into transport vesicle // site for protein synthesisZ: site for ATP/energy generation//site for cellular respiration// produce energy

Able to explain what will happen to the production of extra-cellular enzyme if Golgi apparatus/X absent

Sample answer:F: the production of/ synthesis of (extra-cellular enzyme) is incomplete// no production of enzyme

1111

111

1

1

1

1

1

1

11

Correct spelling only

= 4 marks

F +Any one P= 2 marks

Correct spelling only=1 mark

Any two correct answers= 2 marks

Any 3 points

28

E1: (without Golgi apparatus) the protein can not be modified/ converted (to form cellular enzyme)E2: the protein can not be sortedE3: (enzyme/protein) can not be packaged/packed (into secretory vesicle)E4: no enzyme/ protein will be transported/release/sent out of the plasma

1

1

= 3 marks

T= 12 m

QUESTION 3

No Mark SchemeSub mark

Total mark

1(a) Able to name X and Y.

AnswerX: RibosomeY: Golgi apparatus

11

2(b) (i) Able to give one example of the cell.

Answer Pancreas // Ileum // stomach epithelial cell // salivary cell 1

1(ii) Able to explain the effect on the production of

extracellular enzyme if organelle Y malfunction.

Sample answersF: The production of extracellular enzyme is incomplete /

disrupted / affectedE1: (without Golgi apparatus / Y), the protein cannot be

modified into extracellular enzymeE2: Protein cannot be sortedE3: Extracellular enzyme cannot be released / transported

to the targeted cell / organAny 2

1

1

11

2(c) Able to explain denaturation of enzyme.

Sample answersE1: High temperatures alter / change the (three

dimensional) shape of the active site of enzyme molecules

E2: Substrates thus can no longer fit into the active sites of the enzyme

E3: The reaction cannot be carried out / substrate cannot be hydrolysed

1

11

2

(d) Able to explain the reason why the blood stained cannot be removed

Sample answersE1: Blood is made up of protein

11

29

E2: Protein is broken down / digested by Protease (enzyme)

E3: Therefore the use of Amylase (enzyme) in the detergent powder would not be effective

Any two

1

2

(e) Able to explain the effect of blocked bile ducts to the digestion of lipids

Sample answersE1: Gallstones blocked the secretion of bileE2: Lipids cannot be emulsifiedE3: The rate of lipase reaction will become slower //

digestion of lipids will be disrupted / is incompleteE4: The patient might face obesity // become obese

Any 3E

111

13

Total 12

1 Suggested answer Score

a) Cell A: Metaphase I 1

Cell B: Anaphase II 1

b) i) Centriole 1

ii) To form/ organise the formation of spindle fibres. 1

c) 2

(1 each)

cell A cell B

d) i) X: Crossing over 1

Y: Prophase I meiosis I 1

ii) F1: During phase Y, chromatids condense to form shorter and thicker/ or they become visible.

3

(any three)F2: Nuclear membrane/ nucleolus disappear.

F3: Pairing of homologous chromosomes/ synapsis/ formation of bivalents.

F4: Non-sister chromatids of tetrad might exchange their segments/ genetic materials at chiasma through the process X, crossing over/ exchange of segment.

30

F5: Formation of spindle fibres begins.

F6: Centrioles migrate to opposite poles of the cells.

e) Non-disjunction/ gametes with abnormal chromosome number. 1

Fertilisation of these abnormal gametes forms abnormal zygote.

Any suitable example: Down’s Syndrome/ Turner’s Syndrome/ Klinefelter’s Syndrome.

1

1(any 2)

Total 13

2(a)(i)

(a)(ii)

(b)(i)

(b)(ii)

(b)(iii)

(c)

Able to state the name of cell division in diagram 2.1Sample answer:Meiosis // meiotic division

Able to arrange the sequence of cell division correctly;Stage 1: D stage 2: A stage 3: C Stage 4 : E stage 5: B

criteria: C1: sister chromatids are separated (at centromere)C2: centromeres are facing to opposite poles

Sample answer:2 chromosomes// one pair of chromosome

Able to describe the consequences on the cell division if spindle fiber is absent.

Sample answer:P1:chromosomes/sister chromatids will not be separatedP2: no spindle fiber can pulls the chromosomes to

the opposite poles//chromosomes are not pull to the opposite poles

P3:one of the daughter cell produced does not contain the chromosomes shown in the

1

11

1

1

1

1

1

Reject: meiosis I or meiosis II

5√: 3 m4√:2 m3√:1 m

2 marks

Any three points / P

31

diagramP4:the other daughter cell contains 4 chromatids/

excess chromosomes

Able to state the significance/ importance of cell division in diagram 2.1 and 2.2 to human life

Sample answer;Cell division in 2.1: produces (haploid) gamete cells // ensures the number of chromosomes remain the same from one generation to generation // ensures variation in offspring

Cell division in 2.2 : (ensures) growth process to takes place in human body // repairing damaged tissue // replacing worn out cells

1

1 Reject: repairing damaged cell

Question 3 Marks (a) Mitosis 1(b) L N K M 1(c)(i)

K – AnaphaseN – Metaphase Reject: wrong spelling

11

(ii) K – Chromosome//sister chromatids separates and moves towards opposite poles of the cells/spindleN – Chromosomes line at the metaphase plate// equator of the cell

1

1(d)(i)

X – centromereY – chromatids //non-sister chromatids Reject: wrong spelling

11

(ii) Synapsis of the homologous chromosomesFormation of chiasma and crossing over

11

(iii) Variations to the species/organismEnsure survival/continuation of species

1112

Question 4NUM SCORING CRITERIA MARKS

32

4(a)(i) Able to name the phases based on diagram 2.1

X: Prophase I Y: Anaphase I

X=1Y=1 2

4(a)(ii) State two differences between phase X and Y based on the chromosomal behaviourPhase X Phase YD1:Homologous chromosomes forming bivalent/ pair up/synapsis

D1:Homologous chromosome are separated

D2: centromere of chromosomes are not attached to spindle fiber

Centromere of each chromosomes attached to the spindle fiber and pull to the opposite poles

1

4(b)(i)

(b)(ii)

Able to state the number of chromosome of sperm cell Sample answer: 22+XY // 24

Sample answer:Klinefelter syndromeCh 1: Has female body shape / soft, flawless skinCh 2: frontal baldness//breast development/ small penis or testes

Any 2

1

1

1Max 2

4(c)

4(d)

Sample answer:P1: (high frequency in) radiation kill the cancer cellsP2: retards cell division/growth of cancer tissue

Sample answer:P1: cloning/ tissue cultureP2: oil palms produced do not have variationsP3: if one tree infected by disease, all palm oil trees will be eliminated.

11

111

Max2

No Mark SchemeSub mark

Total mark

33

5(a) (i) Able to name stages X and Y.

AnswerX: Prophase 1Y: Metaphase 1

11

2(ii) Able to state two differences between chromosomal

behaviour at X and Y.

Answer PROPHASE 1 METAPHASE 1

D1: Homologous chromosomes are arranged randomly

Homologous chromosomes are arranged on the metaphase plate / equatorial plane

D2: The centromeres of the chromosomes are not hold by / attached to any spindle fibre

The centromeres of the chromosomes are hold by / attached to the spindle fibres

D3: Crossing over takes place between the non-sister chromatids

Crossing over has already taken place between the non-sister chromatids

Any two

1

1

1

2

(b) (i) Able to state the chromosome number in each of the daughter cell produced.

Answer 12 chromosomes 1

1(ii) Able to state reason for answer in (b)(i).

Sample answersE2: During meiosis, the cell undergoes two nuclear divisions but

the chromosomes / DNA of each chromosome only replicates once

E3: Each daughter cell receives half the number of chromosomes from the parent cell

Any one E

1

1

1

(iii) Able to explain one important event that takes place during stage X

Sample answersF1: Crossing overE1: An exchange of segments of DNA between non-sister

chromatids of homologous chromosomes.E2: Which results in new combinations of genes on a

chromosomeAny two

11

12

34

5(c) Able to draw one daughter cell produced at the end of the meiotic division.

Any one daughter cell with the correct combination of chromosome

D1: Correct drawing of chromosome (number and combination)

D2: Correct drawing of the cell (chromosomes are enclosed in a nuclear membrane)

11

2

(d) Able to explain the effect in a human if the chromosomes fail to separate during stage Y.

Sample answers

35

E1: One of the daughter cells produced might contain one extra chromosome / one lesser chromosome

E2: During fertilization, if the cell with an extra / lesser chromosome fuses with a normal sperm, the zygote shall contain one extra/47 // one lesser/ 45 chromosome/s

E3: Producing Down’s / Klinefelter’s // Turner’s Syndrome baby / offspring

Any two

1

1

1

2

Total 12

ITEM NO.

SCORING CRITERIA MARKS REMARKS

1(a) P1: DNA in the nucleus contain genetic information to synthesize enzymes /protein,P2: ENA copies the information from the DNA for use in enzyme protein synthesisP3: Ribosome synthesis proteins / polypeptidesP4: The protein are transported through the spaces in the RER.P5:( Proteins are transported) by transport vesicles to the Golgi apparatusP7: Here the proteins are modified into enzymes.P8: The enzyme are transported to the plasma membrane by secretory vesicles to be released outside the cell.

1

1

11

1

11

Max 6 Any 6

(b) P1:Molecule X is a polysaccharide /cellulose which consist of many monosaccharides/glucose.P2:The monosaccharides /glucose are join together by condensation to form long chains of polymersP3: Molecule Y is a polypeptide (which consist of many amino acids) P4: Molecule Y is broken down by hydrolysisP5: hydrolysis catalyst by enzyme protease.

1

1

1

1 Max 4

Reject starch/ glycogen

Any 4Ps(c) P1: X-pepsin , Y- salivary amylase, Z-Trypsin

P2: Each enzyme function actively at its optimum pHP3: The enzyme salivary amylase function optimumly at pH 7/neutral P4: The optimum pH of pepsin is pH 2 /acidicP5: Trypsin is pH 8.5 / alkali P6: The changes in ph will cause changes in the concentration of hydrogen ion(H+ and hydroxyl ions(OH_)P7: The excess hydrogen ions or hydroxyl ions destabilize by changing the charges of the active site.P8: Changes on the substrate (surface area) are also changedP9: Hence the enzyme-substrate complex cannot be formed / substrate cannot enter/ fit into the active site.P10: The effects of pH changes on the enzyme activity are reversibleP11: An enzyme which is inactive in high pH medium will become active again when it is in at optimum pH.

111

111

1

11

1

1Max 10

Any 10

36

TOTAL 20

CHAPTER 5: CELL DIVISION (MARK SCHEME)Question 1

a) (i) Similarities :F1-Both involved the division of cytoplasm to produce 2 daughter cellF2 – Both produced two nuclei each with an identical chromosomes

Differences :F1 – In animal cell cytokinesis occurs by formation of cleavage furrow / actin filament while in plant cell cytokinesis occur by formation of a cell plate

11

1

(ii) F1 – Somatic cells from the cow are extracted from the mammary glands / any somatic tissue and placed in culture medium (low nutrient)F2 – An egg cell is extracted from the ovary of female cow / surrogate motherF3 – The nucleus of egg cell is then sucked out / removedF4 – The nucleus of somatic cell fused into the anucleated / egg cell without nucleusF5 – Stimulating them with electric pulseF6 – The fused cell / new cell divides repeatedly by mitosis (in the medium ) to form an embryoF7 – The embryo is implanted into a surrogate mother / female cowF8 – The embryo develops into a new individual and borns as a cloned animal

1

1

1

1

11

1

1

Question2Item no Scoring criteria Marks

a) (i)

(ii)

Organelle – MitochondriaF1 – To provide energy to swim towards the ovum (for fertilization)

Organelle – chloroplastF1 – Contain cholorphyll to absorb energy from sunlight for photosynthesis

11

11

b) E1 – The information for the synthesis of enzymes is carried by DNA in structure Q / nucleusE2 – The information is copied and carried / transferred to ribosome / structure p via RNA / mRNAE3 – The information is used to synthesise protein in the ribosome / PE4 – protein that are synthesized in the ribosome / P are transported through the spaces between the structure R / rough endoplasmic reticulum (RER)E5 – Protein depart ffrom R / RER wrapped in transport vesicles / S that budd off/ from the side of structure R / RERE6 – These transport vesicles/ s fused with the membrane of structure T/ golgi apparatus to be sorted and modifiedE7 – Modified protein is packed into secretory vesicle / UE8 – Secretory vesicles/ U buds off from structure T / golgi

1

1

1

1

1

111

37

apparatus membrane and travel / sent to the plasma membrane E9 – Secretory vesicles / U will release the modified protein / enzyme outside the cell ( as extracellular enzyme)

1

c) Similarities :F1-Both involved the division of cytoplasm to produce 2 daughter cellF2 – Both produced two nuclei each with an identical chromosomes

Diferences :F1 – In animal cell cytokinesis occurs by formation of cleavage furrow / actin filament while in plant cell cytokinesis occur by formation of a cell plate

11

1

d) F1 – Somatic cells from the cow are extracted from the mammary glands / any somatic tissue and placed in culture medium (low nutrient)F2 – An egg cell is extracted from the ovary of female cow / surrogate motherF3 – The nucleus of egg cell is then sucked out / removedF4 – The nucleus of somatic cell fused into the anucleated / egg cell without nucleusF5 – Stimulating them with electric pulseF6 – The fused cell / new cell divides repeatedly by mitosis (in the medium ) to form an embryoF7 – The embryo is implanted into a surrogate mother / female cowF8 – The embryo develops into a new individual and borns as a cloned animal

1

1

11

11

11

Item Criteria Marks Total Marks

1a Able to explain the result of experiment, regarding osmosisSample AnswerF: The level of solution is higher in arm X compared to arm YE1: Process – OsmosisE2: At the beginning of the experiment The solution in arm X is hypertonic compared to arm Y//X is hypertonic solution//Y is hypotonic solution E3: Water molecules diffuse from arm Y to arm XE4: Through the semi permeable membraneE5: At the end of the experiment the osmotic pressure of sucrose is the same / reach dynamic equilibrium 1F and any 3Es

111

111

4 marks

b Able to explain the changes on the plant cell.Sample AnswerIn Sucrose solution P

The cell is placed in a hypotonic (sucrose) solution (compared to cell sap)

Water (molecules) diffuse into cell (sap) By osmosis The vacuole becomes bigger the cells become turgid

In sucrose solution Q The cell is placed in an hypertonic (sucrose) solution

1111111111

(Any 4)

(Any 4)

38

(compared to cell sap) water (molecules) diffuse out from the cell By osmosis (if not mention in above answer) Plasmolysis occur // vacuole /cytoplasm shrinks The cells becomes flaccid

8 marks

c Able to describe the movement of molecules across the plasma membrane into the cellSample Answer:Movement of Potassium ionsF: By Active transportE1: Through carrier proteinE2: Against concentration gradientE3: Use (metabolic ) energyE4: Results in accumulation

Movement of water moleculesF: By OsmosisE1: Through phospholipid bilayer/pore protein/ carrier protein E2: From a region of higher water concentration// outside cell has higher water concentration/lower solute concentration.E3: Passive transport// do not need energy Movement of Vitamin EF: By simple diffusionE1: Through phopholipid bilayerE2: From a region of higher (solute) concentration to a region of lower (solute) concentrationE3: passive transport//do not need energy

11111

Any 3

11

11

Any 3

1111Any 3 8 marks

SCORING CRITERIA MARK

Able to list the general characteristics of enzymes Sample answer

P1 – Enzymes are proteins which are synthesised by living organisms.

P2 – Enzymes bind to their substrates and convert them to product in the

enzymatic reaction

P3 – Enzymes have specific sites called active sites to bind to specific

substrates // enzymes are highly specific in their reaction // each enzyme

can only catalyse one kind of substrate / specific substrate

P4 – Enzymes speed up the rates of chemical reactions but remain

unchanged (at the end of the reaction ) // They are not destroyed by the

reactions they catalyse.

P5 – Enzymes are needed in small quantities because they are not used up

(but released at the end of a reaction)

1

1

1

1

1

39

P6 – Most enzyme-catalysed reactions are reversible // enzymes can catalyse

the reaction in either direction.

P7 – The activity of an enzyme can be slowed down or completely stopped by

inhibitors // In order to function well , many enzymes require helper

molecules,called cofactors.

Able to discuss the uses of enzymes in industrial processes and our daily life, using suitable examples Sample answer

Type of industry/Application

(T)Enzymes

used (E)

Uses (U)

1. Food processing industry

(a)Dairy products

Rennin Solidifies milk proteinsLipase Ripening of cheeseLactase Hydrolyses lactose to glucose in

the making of ice-cream

(b)Bread and other bakery products

(baking industry)

Amylase

Protease

amylase convert starch flour into sugar in the making of the bread

protease convert protein in the making of biscuit

(c)Alchoholic drinks(beer / wine making industry)

Amylase

Zymase

amylase convert starch in malt into glucose for the fermentation of yeast (in wine and beer production.)

Converts sugars into ethanol during fermentation of yeast (in wine and beer production.)

(d)Fish products Protease Protease removes the skin of fish

1

1

11

1

1

1

1

1

11

40

(e)Meat products Protease Tenderises meat(f)Cereal grain

productsCellulase Breaks down cellulose and

removes seed coats from cereal grain

(g)Seaweed products

Cellulose Digest cell wall and extracts agar from seaweed

(h)Starch products Amylase

Glucose isomerase

Change starch to sugar in the making of syrup

Convert glucose into fructose // Production of high fructose syrup

2. Leather products Trypsin /Protease

Removal of hair from animal hides

3. Medical / phartimaceutical product

(Pancreatic) tripsin(Microbial)trypsin

Treats inflammation

Dissolves blood clots

4 .Biological washing powder or detergent

Protease and amylase

Dissolve protein and starch stains in clothes

Able to explain how extracellular enzyme is produced by emphasising on the role of P, Q, R and S

Sample answer

P1– P : nucleus, store genetic imformation / gene (for the synthesis of enzymes) in chromosome / DNA / is carried by the DNA

P2– The messenger RNA/ mRNA is synthesised according to the instruction on the DNA // The genetic information to synthesis the enzyme in DNA is transfered to RNA in code form // mentioning of the transcription process briefly.

P3– Q : mitochondrion, produce energy by cellular respiration (used in the production of extracellular enzyme

P4 –The messenger RNA / mRNA / RNA then leaves the nucleus and moves to the ribosome (which is the site of protein synthesis)

P5– The messenger RNA / mRNA /RNA attaches itself to the ribosomeP6– Protein that are synthesised at the ribosome are transported through the

spaces within the rough endoplasmic reticulumP7– Proteins depart from the rough endoplasmic reticulum wrapped in vesicle

that bud off from the sides of the rough endoplasmic reticulum / from the membranes of the rough endoplasmic reticulum

P8 – These transport vesicles fuse with the membrane of the R, Golgi apparatus / body and empty their contents into the membranous space

P9– These proteins are modified during their transport in the Golgi apparatus, R .

P10– For example, sugar to make glycoproteins/ carbohydrate are added to protein

P11– S, secretory vesicle containing these modified proteins bud off from the Golgi membrane and travel to plasma membrane

P12– These vesicle will then fuse with the plasma membrane before releasing

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

41

the proteins outside the cell as extacellular enzymes.

Grant marks:If student mention the names of P,Q, R and S before or after explaining the process.

42