answer biology paper 2

7/30/2019 Answer Biology Paper 2

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Biology

Paper 220102 ½ jam

JABATAN PELAJARAN MELAKA

PEPERIKSAAN PENGESANAN PERTENGAHAN TAHUN

BIOLOGY

Paper 2

PERATURAN PEMARKAHAN

UNTUK KEGUNAAN PEMERIKSA SAHAJA

Peraturan pemarkahan ini mengandungi 19 halaman bercetak



MARK SCHEME

QUESTION 1

ItemNum.

Answer Marks Remark

1 (a) Able to name organelles labeled X, Y and Z

Answers:

X : RibosomY : Golgi apparatusZ : Secretory vesicle

.

111 3

(b) Able to to state the function of X

Answers:

Sites of protein synthesis 1 1

(c) Able to explain why organell W is foundabundantly in the cell.

Sample answers:

Organell W / mitochondrion involved incellular respirationThis process released energy to be used bythe cell to make protein.

1

1 2

( d )(i)

(d)(ii)

Able to state the type of structure shown.

Answer:

Tertiary structure

Able to give one example of the proteinstructure

Answer

Enzyme/ Hormones/ antibodies/albumin

1

1 2



ItemNum.

Answer Marks Remark

(e)(i) Able to suggest one way to make washingmore effective

Answer:

Use warm water 1 1

(e)(ii) Able to explain how answer in c(i) affect therate of bio enzyme reaction

Sample answer:

- Temperature increase (until optimumtemperature)

- collisions between substrate and enzymemolecules occur more frequently

- rate of reaction increase

1

1

1 Max 2

(e)(iii) Able to give one example of bioenzyme Y.

Answer:

Protease / Amylase 1 1



QUESTION 2

ItemNum.

Answer Marks Remark

2(a)(i)

(a)(ii)

Able to state the food class labeled R

Answer:

Carbohydrate

Able to state the main function of food fromgroup R

Answer:

Provide energy

1

1 2

(b)(i) Able to state which food class is good for pregnant woman and explain.

Sample Answers:

Group R

- They are protein and good for the formationof new tissues

Group Q- Source of fibre which help to prevent

constipationGroup P- Provide energy to support the growing

foetus

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1

1 3

(b)(ii) Able to state which type if food class shouldbe avoided and explain.

Sample answers:

Fat- When bile duct is blocked, bile cannot be

channeled out.- Lipids cannot be emulsified / difficult to be

digested.

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1 3



ItemNum.

Answer Marks Remark

(c)(i)

(c)(ii)

Able to calculate the amount of energyobtained from the food.

Answer:

2575.1 kJ

Able to state the energy content of butter andexplain.

Answer:

3062 kJ

Able to explain why the energy content of 100g of butter as calculated.

Sample Answer:

Fats has twice more energy content for thesame 100g of carbohydrate

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1

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2



QUESTION 3

ItemNum.

Answer Marks Remark

2(a) Able to circle and label one example in thepond

(i) Secondary consumer – Small fish

(ii)Tertiary consumer – Big fish

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1 2

(b) Able to state the niche of prawn

Prawn eats plankton // Big fish eats prawn 1 1

(c) Able to explain the role of Lemna sp andLotus sp. on the changes of organic matter onthe base of the pond.

P1 These plants prevent sunlight from

reaching the submerged plants

P2 The submerged plants die because theycannot carry out photosynthesis

P3 The decomposed remains of thesubmerged plants add more organicmatter on the base of the pond

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1

1

Max 2



Item

Num.

Answer Marks Remark

(d)(i) Able to calculate the total energy absorbed bythe swan

Answer

10/100 X 35000 kJ = 3500 kJ10/100 X 3500 kJ = 350 kJ10/100 X 350 kJ = 35 kJ absorbed by theswan

111 3

(e)(i) Able to explain how the excess fertilizer pollute the freshwater pond

Sample answers:Draining of excess nutrient from the fertilizer into the pond

Encourage the rapid growth of algae

The excessive growth of algaerestricts the penetration of light intothe water

And when they die,decomposer usedup all the dissolved oxygen/supply of

oxygen in the pond decrease

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1

1 Max 2

(e)(ii) Able to explain briefly how to determine thepollution level of the pond

Sample Answer

- Add methylene blue to sample of pond water - Time for decolourisation indicate the level of

pollution- If the sample decolourise in a short time, the

pond water has a high level of pollution.

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1 Max 2



QUESTION 4

ItemNum.

Answer Marks Remark

4(a)(i)

(a)(ii)

Able to name muscle R

Answer:

Myotome

Able to state one characteristic of muscle R

Answer:

When the muscles on one side contract,those on the other side relax

1

1

1

1

(b) Able to explain the action of muscle R thatenable fish to swim.

Sample Answers:

P1 When the muscles on one side contract,

those on the other side relaxP2 The body bends toward the side of

myotome muscle that contractP3 Alternating waves of contraction and

relaxation pass down from head to tail

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1 3

(c) Able to explain how the injury affect itsmovement.

Sample answers:

Become unstable in water leading toYawing (side way movement) andRolling (transverse plane movement)

11 2



ItemNum.

Answer Marks Remark

(d) Able to explain how the leg muscles help thegrasshopper in jumping

P1 In the position at rest (flexor musclecontracts), the hind leg folded in the Z-shaped/ poised for a jump

P2 When extensor muscle contracts (theflexor muscle relaxes), the hind leg jerkbackward, grasshopper jump

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1 2



QUESTION 5

Item

Num. Marking Criteria Marks

Remark

5 (a) Able to state three differences between thecomposition of the glomelular filtrate in T andtubule V.

Sample answerT Tubule V

Contains glucose Do not containglucose

Contains amino acids Do not contain aminoacids

Contents of water,

sodium and chlorideions is the same as inblood plasma

Less contents of

water, sodium andchloride ions as thesesubstances has beenreabsorbed

1

1

1 3

(b) Able explain how the cells are structured.

Sample answer:

They have many/abundant mitochondria

Produce a lot of energy needed for activetransportor

Numerous/many microvilli

Increase total surface area for reabsorption

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11

2

(c) Able to explain how the concentration of thesubstances present in Q changes:

Sample answer After taking sea food

Sea food contains high protein/ main sourceof amino acid

(Excess) amino acids are deaminated /

converted into ammonia / urea in the liver The urea is transported to the kidneys and

removed as urine

The concentration of urea in the urine wouldincrease

After taking salty food

Increase blood osmotic pressure

More ADH is released

Increase permeability of tubules

Less urine and more concentrated

1

1

1

1

1111

2

2

Any two

Any two



ItemNum.

Marking Criteria MarksRemark

(d) Able to explain how the dialysis machine

replaced the function of kidney

Sample answer:P1 – blood from patient enters dialysis machineP2 – net diffusion of toxins occurs from blood todialysis solution.P3 – required ions and glucose may also beadded to the dialysissolution,P4 – resulting in their net diffusion into the blood.P5 – filtered blood re-enters the patient’s bloodvessels

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1

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Max3



QUESTION 6

ItemNum.

Answer Marks Remark

6(a)(i)

(a)(ii)

Able to name the type of cell division andexplain.

Sample answer:MitosisProduce two daughter cells with diploid (2n)chromosome / same as the parent cell.

Able to define the meaning of the cell division

named operationally.

Sample answer:

Mitosis is a cell division process which startswith nucleus division followed by cytoplasmicdivisionto produce two daughter cells with 2nchromosome / same as the parent cell

11

1

1

2

2

(b) Able to explain how to propagate the good

quality of Exotica papaya.

Sample answers:

Technique – Tissue culture

P1- Small pieces of tissue(explants)taken from sterilized parent plant.

P2- The explants are then placed inside atest tube containing nutrient andgrowth hormones.

P3- Plant cells divide by mitosis to form a

callus (undifferentiated mass of tissue)

P4- Cells in the callus develop intoembryo and later into plantlets

P5- The rooted plantlets are thentransferred to soil and kept incontrolled environment until theygrow into adult plants

P6- From one original plant, hundreds of genetically plants could be produced

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Max 5



ItemNum.

Answer Marks Remark

6(c) Able to describe four similarities and six differences.

Sample answer:

Similarities1 .Both involve nuclear division2. Both produce two daughter cells3. Both start with diploid cell4. Both ended with cytokinesis

Differences

Mitosis Meiosis IProphaseF1 Synapses absent

F2 Crossing over /exchange of geneticmaterial absent

ProphaseF1 Synapses present

F2 Crossing over /exchange of geneticmaterial occur betweenhomologous chromosome

MetaphaseF3 Chromosome line up atequatorial plate

MetaphaseF3 Homologouschromosome line up atequatorial plate

AnaphaseF4 Sister chromatidseparate. Chromatid ispulled to opposite poles

AnaphaseF4 Homologouschromosome separate.Chromosome is pulled toopposite poles

TelophaseF5 Four chromatids in acell

F6 Two genetically similar daughter cells areproduced.// No variationbetween the cell

F7 The cells produced arediploid cells

TelophaseF5 Two chromosomes in acell

F6 Two geneticallydifferent daughter cells areproduced.// The two cellsvary from each other

F7 The cells produced arehaploid cells

1111

1

1

1

1

1

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4

Max6

Must have4

similarities

and 6differences



QUESTION 7

ItemNum.

Answer Marks Remark

7(a) Able to explain the formation process of fluidP.

Sample answer:

E1 When the blood flows from the arterioleinto the capillaries, there is a highhydrostatic pressure

E2 due to the pumping of the heart andresistance in the capillaries

E3 forces the plasma to pass across one-cell-thick capillary walls into spacesbetween the cells

E4 consisting small molecules of dissolvedsubstances like water, minerals, glucoseand amino acids

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1

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1 4

(b) F: Able to state the immunity correctlyP: Able to explain why the baby has been

diagnosed with Hepatitis B.

Sample answer :F1 – Artificially acquired active immunity

P1 – Vaccination/ vaccine injectionP2 – it will activate the body to produce

antibodiesP3 – Result in the production of a low level of

antibodies concentrationP4 – (but) the dose does not sufficient to

protect against the disease

P5 – second booster dose is necessaryP6 – to increase antibody production over a

level of immunity

(any 5P)

1

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1

11 6



ItemNum.

Answer Marks Remark

7(c) Able to explain the statements to justify that lymphaticsystem is a complementary to circulatory system.

Lymphatic system is a complementary to circulatory system

Sample answer:

F1 Collect the interstitial fluid and return it to the circulatorysystem via the subclavian vein

F2 Defend the body against diseaseF3 by producing lymphocytes which release antibodies to

react with antigensF4 To transport lipids, glycerol and fat soluble vitamins A,

D, E and KF5 from the lacteal (lymph capillary) of the villusF6 into the thoracic duct back the circulatory system via

the left subclavian vien.F7 To transport water, hormones, glucose, amino acids,

minerals and heat in the interstitial fluidF8 that diffuse into the lymphatic system back to the

circulatory system again

F9 To transport the waste products such as CO2 andnitrogenous compounds in the interstitial fluid

F10 that diffuse into the lymphatic system to be excreted bythe lungs and kidneys

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1 10



Enz me rennin

QUESTION 8

ItemNum.

Answer Marks Remark

8(a) Milk does not react with the enzyme in the mouth/R andenters the stomach through the esophagus.

F1: Digestion in the stomach / SP1: Gastric glands in the walls of the stomach secrete

gastric juiceP2: Gastric juice consists of hydrochloric acid and the

enzymes pepsin and renninP3: Rennin coagulates milk by converting the soluble

milk protein caseinogen into the insoluble casein.Caseinogen casein

P4: Casein is then hydrolysed by enzyme pepsin to peptoneand polypeptide.

Casein + water enzyme pepsin peptone + polypeptide(any 3P)

F2: Digestion in the duodenum /TP5:The enzyme trypsin hydrolysed peptone and

polypeptide into peptidesP6:Fats in the milk is emulsified by the bile to be broken

down into tiny droplets//bile emulsifies fats by breakingup large globules of fats into small fat droplets inorder to increase the surface area for the action of enzyme lipase

P7: The enzymes lipase hydrolyses fat into glycerol andatty acids.

Fats + water enzyme lipase glycerol + fatty acids

F3: Digestion in the ileum/UP8: The enzyme erepsin (peptidase) hydrolyses peptide

to amino acids.Peptide + water enzyme erepsin amino acid

P9: The enzyme lactase hydrolses lactose to glucoseand galactoseLactose + water enzyme lactase glucose + galactose

P10:The enzyme lipase hydrolyses fats (emulsifies)to glycerol and fatty acidsFats + water enzyme lipase glycerol + fatty acids

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1 Max10



ItemNum.

Answer Marks Remark

8(b) Able to explain the effects of consuming the menu setfor a period of time

Sample answer

P1 : The menu is not a balanced diet // does not containthe 7 classes of food in appropriate ratio

P2 : Menu is highly rich in carbohydrates and fats // novegetables and lack of vitamins //Higher energyintake compare to energy requirement for a girl

aged 15

ConsequencesSample Answer

P3 : ConstipationP4 : lack of fiber , faeces moving to slowly through the

colon

P5 : ScurvyP6 : lack of vitamin C //any other vitamins deficiency

with explanation

P6 : ObesityP7 : increase in body weight drastically due to energy

requirement is less then energy intake

P8 : Diabetes mellitusP9 : excess of glucose contain in blood , food is highly

rich in carbohydrates

P10 : ArteriosclerosisP12 : fats deposited in the lumen of blood vessel

P13 : Heart attackP14 : blockage in the coronary artery //

Any other cardiovascular diseases withexplanation

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8

Any 4 consequences with explanation



QUESTION 9

ItemNum.

Answer Marks Remark

9(a) Able to explain why most plants cannot colonize and grow inthe swamps

Sample answer

P1: The ground is too soft and unable to support plants.P2: The water-logged/muddy swamps provide very little

oxygen for root respiration.P3: The swamp water has a high concentration of salt and

is hypertonic.P4: The plants growing in swamp will have the problem of

dehydration.P5: Seeds that fall into the muddy swamp will die of

dehydration/insufficiency of oxygen.P6: The swamp is exposed to strong sunlight and intense

heat.P7: As a result, the plants growing there will lose water

very fast by transpiration.

Able to explain how the mangrove trees adapt themselvesto the harsh living conditions

Sample answer

P1: Root system which is highly branched and spreadsover a big area to give good support to the plants.

P2: Pneumatophores (breathing roots) which growprotruding upwards above the ground.

P3: The plant cells have high concentration of cell sap.P4: Hence, the cells are able to withstand the high salt

contents of the swamp.P5: Excess salt is eliminated through hydatodes found at

the lower epidermis of leaves.

P6: Viviparous seeds which germinate while still attachedto the parent plant.

P7: The long radical produced will let the seedling stick intothe ground and not submerge or drift away.

P8: Thick cuticle and sunken stomata which help to reducethe rate of transpiration.

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1Max

10

Any 5P

Any 5P



ItemNum.

Answer Marks Remark

9(b) Able to the effects of unplanned development and improper management on the ecosystem

Sample answer

P1: The leave canopy in the forest protects the soil fromexcess rain water.

P2: When the forest is cleared, the soil is exposed to rain(water)/wind.

P3: this will cause soil erosion.P4: The soil that is exposed to wind will be blown to

another area.P5: While soil that is exposed to rain water will be eroded

and deposited at the bottom of the river/pond/lake.P6: The soil at the hill slopes can (also) be washed away

by heavy rain water P7: resulting in land slides.P8: (The deposited soil will) cause the water level to

increase rapidly when it rains andP9: this will in turn cause flash floods.P10: Wild life species will also be threatenedP11: when their habitat is destroyed.P12: Global warming will occur

P13: due to an increase in the Earth’s temperature,P14: which is caused by excess emissions of carbon

dioxide/methane/CFC/nitrogen dioxide (into theatmosphere).

P15: These gases trap the heat that us reflected by theEarth.

P16: The thinning of the ozone layer occursP17: when the ozone layer (that protects the Earth from

ultraviolet radiation) is destroyed bychlorofluorocarbons (CFC).

1

1

11

1

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11

1111

11

1

11 Max

10

answer biology paper 2

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