Ans Paper 2 Selangor

PROGRAM PENINGKATAN PRESTASI AKADEMIK SPM2010

BIOLOGY MARK SCHEME

PAPER 2

JABATAN PELAJARAN NEGERI SELANGORPERSIDANGAN KEBANGSAAN PENGETUA SEKOLAH

MENENGAH

Question 1QuestionNum

Criteria MarksSub Total

1(a) ( i ) Able to name structures P,Q and R

AnswerP : Golgi ApparatusQ: Rough Endoplasmic ReticulumR : Mitochondria

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1(a) ( ii ) Able to state the function of R

Sample answer

R : site for cellular respiration // to generate / produce energy 1

1

1 (b ) Able to explain how P and Q play the role in transporting extracellular enzyme

Sample answer

P1 : The nucleus / RNA instructs ribosomes to synthesized proteinP2 : The synthesized protein is transported in the Rough Endoplasmic Reticulum / QP3 : to the transport vesiclesP4 : then the Golgi Apparatus / P packages / modifies / sorts / transports the synthesized proteins P5 : to the secretory vesicles to be transportedP6 : out of the cell through the plasma membraneAny four

1

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1( c ) Able to explain the importance of the occurrence of the stage to the organism

Sample answer

P1 :The stage is Prophase 1P2 : ( During the stage ) Crossing over (occurs between the pair of homologous chromosomes)P3 : (resulting the) gametes (formed to)P4 : (have) different (content of) genetic materialsP5 : (thus will cause) variation (in organism)P5 : (for) better adaptation (in the environment)P6 : (greater chance of) survival (of the species)Any 4

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Total 12

Pectoralis Major Muscles

Question 2No Criteria Marks

2(a) Able to state two types of muscles that involved in the movement of an earthworm.Answer1. Circular muscles2. Longitudinal muscles

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2(b) Able to explain the circular muscles and longitudinal muscles action that allow the earthworm to move forward.Sample answerP1: Circular muscles and longitudinal muscles / both muscles act antagonistically // A pair of antagonistic musclesP2: The contraction of circular muscles // relaxation of longitudinal musclesP3: Cause the segments (of the earthworm) to extend / be longerP4: The contraction of longitudinal muscles // the relaxation of circular muscles P5: Cause the segments (of the earthworm) to shorten /shorterAny 3

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2(c) (i) Able to label the pectoralis major muscles.Answer

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2(c) (ii) Able to state one organelle that can be found abundantly in muscle cells.AnswerMitochondrion / mitochondria 1

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2(c) (iii) Able to explain why muscle cells has abundant number of mitochondrionSample answerP1: to produce (a lot of) energy (in a form of ATP) / ATPP2: for the contraction (and relaxation) of the muscle

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2(d) Able to explain why the bones of a female bird which lay eggs are more brittle as its age increasesSample answerF1 : (Bird’s) bones mass decreasesE1 : as the bones are more porous / lighterE2 : (since it had) lay many eggsE3 : much calcium / phosphorus / phosphates used in forming the

shells of the eggs E4 : leaving less / little calcium / phosphorus / phosphates used to form

(strong) bones // more bone minerals to be lost than deposited // re-absorption of calcium / phosphorus / phosphates into the blood stream is more than the withdrawing of calcium (during the formation of bones)

Any 3

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TOTAL 12


3 (a) Able to name the cell type that matches its respiration equation

Answer:Muscle cellsYeast cells

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3(b)(i) Able to state the types of respiration: Answer:Muscle cells : Aerobic respirationYeast cells: Anaerobic respiration

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3(b)( ii) Able to state 4 differences in the type of respirationSample answers:

Muscle cells Yeast cellsNeed the presence of oxygen

Oxygen absent

Complete oxidation of glucose

Incomplete oxidation of glucose

Occurs in mitochondrion Occurs in cytoplasmMore /2898 KJ energy produced

Lesser / 210 KJ energy produced

Carbon dioxide + Water + 2898 KJ Energy

Carbon dioxide + Ethanol + 210 KJ Energy

Any 4

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1

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3(c) Able to explain what happen to the yeast cells when too much ethanol is produced

Sample answerP1 : (Too much ethanol ) causes unsuitable medium /

condition // Toxic / poisonous medium / conditionP2 : for yeast cells to reproduced // yeast cells die

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3(d) Able to explain the condition of a person after completing a 100 meter race in 12 seconds

Sample answerF : the person is panting / higher breathing rateE1 : as he is in oxygen debt // anaerobic respirationE2 : much lactic acid is produced (in his muscle cells)E3 : causes muscle crampAny two

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TOTAL 12


Sub Total4 a ( i ) Able to name the type of response

AnswerTropism / phototropism

Able to describe the responseSample answerP1 : the plant shoot grows / bendsP2 : towards light

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4 b ( i )

4 b ( ii )

Able to explain why the plumule grows towards direction XSample answerE1 : auxin stimulates / promotes cell elongation at the shoot ( tip )E2 : more auxin is distributed at the darker / lower side of the shoot (tip comparing to the bright / upper side)E3 : (so at the darker / lower side) the rate of cell elongation is higher (than the bright / upper side) E4 : the shoot ( tip ) grows / bends towards light /away from gravity.

Able to explain why the radicle grows towards direction Y.Sample answerE5 : (High concentration of) auxin inhibits cell elongation at radicle /

root ( tip )E6 : more auxin is distributed at the lower / darker side of the root ( tip

comparing to the upper / brighter side)E7 : so at the lower / darker side of the root ( tip ) the rate of cell

elongation is slower (than the brighter / upper side) E8 : so the root grows / bends downward toward gravity / away from

lightAny 6

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6

4 ( c ) Able to state one difference in the role of auxin in shoot tip compared to root tip.Sample answerP1 : At shoot ( tip, high concentration of ) auxin stimulates cell elongation) but at root ( tip ) auxin inhibits cell elongation

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4 ( d ) Able to explain one importance of the response to the plant

Sample answerF1 : Positive Phototropism // Negative Geotropism E1 : enables the plant to receive maximum amount of sunlight for photosynthesis // any suitable explanationORF1 : Negative Phototropism // Positive GeotropismE1 : enables the root ( hair ) to absorb nutrients / mineral salts from the soil // any suitable explanation

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TOTAL 12


5(a) Able to state the genotype of the black colour wing and the genotype of the pale and speckled wing AnswerGenotype of black colour wing : BB / BbGenotype of pale and speckled wing : bb

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( b ) Able to state the dominant trait and give an explanation Sample answerDominant trait : Black colour wingExplanation :E1 : More number of moth are black colour // There are three black colour moth and only one pale and speckled wing // 75 % of the

moth have black colour wing while 25% of the moth have pale and speckled wing // The presence of dominant gene / B.

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( c ) Able to explain how the offspring inherits the pale and speckled wingSample answerP1 : Both parents are heterozygous / have genotype BbP2 : during meiosisP3 : the (male) gamete receive allele B or b // the (female) gamete receive allele B or bP4 : during fertilizationP5 : the male gamete with allele b fused with female gamete with allele b (so the offspring has genotype bb // pale and speckled wing) Any 3

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( d ) Able to state one importance of the difference in wing colour to the mothSample answerP1 : to have varieties in colour of the moth // variationP2 : better adaptation to the environment // camouflageP3 : better survival of the spesies // Any suitable explanationAny 1

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(e) (i) Able to name the process that causes the occurrence

AnswerMutation / Deletion / Chromosomal mutation

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(e) (ii) Able to explain how the mutagen causes the occurrence

Sample answerF1 : Mutagen is radioactive radiation / X-ray / formaldehyde / carcinogens

/ monosodium glutamate // Any suitable exampleE1 : The mutagen has high penetrating power // high radiation // mutagen

able to reach the DNA in the cells / nucleus / chromosomesE2 : causing (drastic) change to the structure of the chromosomeE3 : resulting section P to be deleted // gene P to be missing Any 3

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TOTAL 12


6(a) Able to explain how glucose is transported across the cell through X.Sample Answer:

F: By facilitated diffusionE1: with the aid of carrier protein / XE2: when the concentration of glucose at the outside cell is higher

(than inside cell)E3: glucose binds with (the active site of) the carrier protein / XE4 : Carrier protein / X changes shapeE5: allowing glucose to move into the cellE6 : Carrier protein resumes / change to its original shapeE7 : no energy is needed for the transport process Any 4

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6 ( b ) Able to explain the absorption and assimilation of digested food.Sample Answers: F1 : ileum has (the adaptive features such as having) many villi /

villus / very thin cell wall / villus are surrounded by dense network of blood capillary / lacteal

E1 : to increase the rate of diffusion of the digested foodE2 : glucose diffused from villi into the blood capillary to the liver

via the hepatic portal vein E3 : excess glucose is converted to glycogen (to be kept in the

liver)E4 : glycogen acts as stored food E5 : In body tissue,glucose is oxidized during cellular respiration

to produced energyE6 : amino acids from villi diffuse into blood capillary to the liver

via the hepatic portal veinE7 : excess amino acids is deaminated / converted into urea (to

be excreted through the kidney)E8 : amino acid will be used to synthesis new protoplasm / repair

of damaged tissues// used to synthesis proteins of plasma membrane//produce enzymes/antibodies/hormones

E9 : fatty acids diffuse from villi into lactealE10: then transported to the thoracic duct /right lymphatic vessel// lymphatic vesselE11: to the subclavian veins back to the blood circulatory systemE12: fatty acids is synthesized to form the plasma membraneE13 : stored in the adipose tissues (beneath the skin as a source of energy)Any 10

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6 ( c ) Able to explain how the treatment can help a person to reduce body mass

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Answer:P1: Small intestine is the site / organ where digestion /

absorption of (digested) food occurP2 : Slower rate of hydrolysing of food (to simplest food) P3 : ileum / small intestine (has intestinal gland to) produce (intestinal juice containing digestive enzymesP4 : shorter ileum has lesser villi / lower surface areaP5 : so the rate of diffusion of digested food is slower P6: less digested food is absorbed into blood capillary from the villusP7: the body tissue received less glucose (to undergo cellular respiration)P8: lack of glucose will cause the adipose tissues / stored fats to

be oxidized/used to produce energyP9: reducing the amount of fats stored // increasing the amount of fats usedP10: thus reducing the body mass Any 6

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TOTAL 20


7 ( a ) Able to explain the how W is formedSample answerF : When there is cut in the blood vessels E1: (a group of) platelets clump / stick togetherE2 : to release trombokinase / thromboplastinE3 : ( thrombokinase / thromboplastin ) converts prothrombin to trombinE4 : ( thrombin ) converts fibrinogen to fibrins / structure W ( fibrins/ W traps erythrocytes / red blood cells )E5 : then forms scab ( scab dried) / wound is healedAny 4

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7( b ) ( i) Able to explain the composition of fluid in P and QSample answerF1: Fluid P is red in colour, fluid Q is colourlessE1: because fluid P has haemoglobin, fluid Q does not have haemoglobinF2: Fluid P contain red blood cell, fluid Q has no red blood cellE2: because the red blood cells are too large to diffuse / move

out of the blood capillary ( to form interstitial fluid )F3: Fluid P contain blood cells and blood plasma, fluid Q only contain blood plasma without protein plasmaE3: because the protein plasma are too large to diffused out of the blood capillaryF4 : Fluid Q contain more lymphocytes , Fluid P contain less

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lymphocyesE4 : because as fluid Q flows through the lymphatic nodes , lymphocyes are produced.Any 3 pairs of F and E.

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7( b )( ii ) Able to explain how fluid in Q is formedSample answerF : The blood / the blood capillaries has very high hydrostatic

pressureE1: forcing the blood plasma without the plasma proteins /

erythrocytes / plateletsE2: to diffused out into the spaces between the tissuesE3: to form intestitial fluidE4: (90% of the intestitial fluid diffused back into the blood capillary but) 10%/small quantity of the fluid diffused E5: into the lymphatic capillaries ( the vessels with blunt end)E6: forming lymph/lymphatic fluid / fluid QE7: consisting of blood plasma without protein plasma / contains glucose,water, amino acids, minerals, vitamins )Any 5

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7 ( c ) Able to explain the importance of the lymphatic system

F1: maintaining the composition of blood E1: the 10%/ small quantity of the interstitial/body fluid / blood

plasma without the protein plasma diffused back (from the lymphatic system) into the blood circulatory system ( diffused into the right and left subclavian veins from the right lymphatic duct and the thoracic duct )

F2: Acts as a body defenceE2: the lymphocytes which are produced in the lymphatic nodesE3: produced antibodyE4: spleen produces phagocytesE5: to kill pathogensE6- and filters pathogenAny 5

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TOTAL 20

Question 8

No Criteria Marks8(a) Able to describe how double fertilization occurs in a plant.

Sample answers:

P1: Anther produces pollen grains / male gameteP2: Pollen mother cell (in the anther) undergoes meiosis to produce (four) megaspores (n) / haploid cells / tetradP3: Megaspores (n) / haploid cells / tetrad develop into pollen grainsP4: The nucleus of each megaspore (n) / haploid cell / divides by mitosis P5: to form one tube nucleus and one generative nucleusP6: (When a pollen grain falls on the stigma,) the secretion of sucrose solution on the stigma P7: stimulates (the pollen grain to germinate to) form pollen tubeP8: (During the growth of pollen tube) the generative nucleus divides mitoticallyP9: to produce two male gametes.P10: the two male gametes move/follow behind the tube nucleus (down

the pollen tube until they) reach the micropyle and enter ovule (for double fertilization)P11: the tube nucleus disintegrates and the two male gametes enter the

embryo sac.P12: (During double fertilisation) one male gamete fuses with the egg cell/ovum to form a diploid zygote and P13: the other male gamete fuses with the two polar nuclei to form a triploid nucleus (so double fertilization occurs ) Any 10

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8(b) Able to describe the advantages of birth control methods in family

Sample answers:

Contraceptive pillP1: contains oestrogen / progesterone hormoneP2: (oestrogen / progesterone hormone) can prevent the formation of follicles in the ovary P3: prevents ovulation // inhibits the secretion of Follicle Stimulating Hormone / FSH / Luteinising Hormone / LH P4: no fertilization occur // the woman is not pregnantP5 : efficient / safe method (of birth control)

Intrauterine deviceP6: (Intrauterine) device is inserted into the uterus (by doctors).P7: left in the uterus (for approximately two, three and five years)P8: irritates the endometrium / prevents the thickening of the uterine wallP9: Prevent the implantation of embryo P10: No development of zygote / no pregnancy

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P11 : efficient/safe method (of birth control)

VasectomyP12: the vas deferens are tied / cut in a surgical operationP13: the sperms are still produced but cannot be transferred out / reach the uterus / Fallopian tubeP14: no fertilization P15 : efficient/safe method (of birth control)(P5, P11 and P15, mark awarded once only)Any 10

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Total 20


9(a) Able to explain the importance of maintaining the biodiversity in the pond ecosystem.

Sample answer :

F1: as a source of food E1: fish / any suitable example has a high protein content / any suitable food class contentF2 : as a source of oxygen supplyE2: the green plants undergo photosynthesis ( during photosynthesis oxygen is produced ) F3 : as a source of carbon dioxide supplyE4 : the organism undergo respiration (during respiration carbon dioxide is produced )E5 : a balanced carbon cycleF4 : as a source of clean water supplyE6 : the dead organism are decomposed by the bacteria/fungiF5 : interaction between plants and animalsE7 : the consumers depend on the producer for foodE8 : in the food chain / food webE9 : energy flow from one tropic level to another tropic levelF6 : as a habitat for plant /animals /any suitable exampleE10 : the suitable conditions allow the organism to breed / increase the population / varieties E11: resulting in biodiversity E12 : a balanced ecosystem

Any 10

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9(b) Able to discuss how the activities endanger the ecosystem 10

Sample Answer: F1: ( CFC ) causes depletion of ozone layerE1: Penetration of excess/more UV rays E2: Skin cancer/melanoma/sunburns/cataract // Any suitable exampleE3: Reduces body immune systemE4: Leaf cells and chlorophyll are easily damaged // Lower rate of

photosynthesisE5: Kill microorganisms / phytoplanktonE6 : Disruption/destruction of food chain/web E7 : Climatic changes // Any suitable example E8 : Surrounding temperature increases

F2: ( Combustion of fossil fuel ) causes acid rain // air pollutionE7: Factories release a large amount of nitrogen oxide/nitrogen dioxide/sulphur dioxide/carbon monoxides / dust in the

atmosphere.E8: Acid rain – soil become acidic (so less suitable for the cultivation of certain crops) // lower yieldE9: Disruption of food chain / food webE10: Photosynthetic tissues are destroyed// Roots damaged and cannot absorb minerals/water//lower rate of photosynthesisE11: Metal railings / bridges corrode/ any suitable exampleE12: Health problem: asthma/bronchitis/ and suitable respiratory problemE13: Skin and eye irritation / conjunctivitis Any 10

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TOTAL 20

Ans Paper 2 Selangor

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