stpm trial 2009 bio q&a (pahang)

8/14/2019 STPM Trial 2009 Bio Q&A (Pahang)

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PEPERIKSAAN PERCUBAAN

SIJIL TINGGI PERSEKOLAHAN MALAYSIA

NEGERI PAHANG DARUL MAKMUR 2009

BIOLOGY

PAPER 1

MULTIPLE-CHOICE

ONE HOUR AND FORTY-FIVE MINUTES

Instructions to candidates

DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO

There are fifty questions in this paper. For each question, four suggested

answers are given. Choose one correct answer and indicate it on the multiple-

choice answer sheet provided. Read the instructions on the multiple-choice

answer sheet carefully. Answer all questions. Marks will not be deducted for

wrong answers.

CONFIDENTIAL *

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1 Which one of the following is a characteristic of saturated fats that distinguishes them

from unsaturated fats?

A They have no double bonds between their carbon atoms

B They contain only unbranched fatty acids

C They contain high proportion by mass of oxygen

D They do not contain glycerol

2 Which part of a phospholipid molecule contributes most to the thickness of a cell surface

membrane?

A Glycerol

B Hydrocarbon chain

C Hydrophilic head

D Phosphate group

3 What does a haemoglobin molecule contain?

A Four iron (Fe2+

) ions attached to each haem group

B Four oxygen molecules attached to each haem group

C Four polypeptide chains each with four attached haem groups

D Four polypeptide chains each with one attached haem group

4 Potassium cyanide is known to interfere with the formation and use of ATP in cell

metabolism. If the use of potassium cyanide resulted in an accelerated entry of a solute

into a cell, it may be reasonably assumed that, under normal circumstances, the solute

enters by

A Active transportB Osmosis

C Passive diffusion

D Pinocytosis

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5 Which cell component forms pinocytic vesicles?

A Lysosome

B Nucloelus

C Cell surface membrane

D Endoplasmic reticulum

6 A culture of bacteria had their entire DNA labelled with the heavy isotope of nitrogen,

15N. The culture was then allowed to reproduce using nucleotides containing normal

14N.

The DNA was examined using a centrifuge after one generation and again after two

generations. The diagram shows the position of the DNA band at Z in the centrifuge tube

when the DNA was first labelled.

X

Y

Z

In which patterns would the DNA be found after the first and after the second cell

generations?

After first generation After second generation

A Half at X and half at Y Quarter at X and at Z and half at Y

B Half at X and half at Z Quarter at X and at Z and half at Y

C All at Y Half at X and half at Y

D All at Z Half at Y and half at Z

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7 Turgid plant tissue is placed in a solution which has the same solute potential as the

contents of the cells. The diagram shows a cell after one hour.

Which equation describes the value of the pressure potential for this cell?

A Pressure potential = solute potential of the cell

B Pressure potential = solute potential of the external solution

C Pressure potential = water potential of the cell

D Pressure potential = zero

8 A metabolic pathway is shown below.

Enzyme 1 Enzyme 2 Enzyme 3

Reactant substance X substance Y end product

What would be the effect of adding a small amount of a non-competitive inhibitor to

enzyme 2?

A Enzyme 2 would be partially denatured

B Substance X would increase in concentration

C Substance Y would no longer be formed

D The initial reactant would no longer be metabolised

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9 Which statement is true of photophosphorylation?

I High energy phosphate bond is split

II High energy phosphate bond is formed

III It occurs in the thylakoid membrane

IV Light is transformed to chemical energy

A II, III, and IV

B II and III

C II and IV

D I and III

10 The following scheme shows a pathway in the formation of fatty acids in plants.

CO

RuBP W X Y Z

Fatty acid

Which of the following compounds are represented by W, X, Y, and Z in the above scheme?

W X Y Z

A Pyruvate Phosphoglyceraldehyde Phosphoglycerate Acetyl CoA

B Phosphoglyceraldehyde Acetyl CoA Phosphoglycerate Pyruvate

C Phosphoglycerate Phosphoglyceraldehyde Acetyl CoA Pyruvate

D Phophoglycerate Phosphoglyceraldehyde Pyruvate Acetyl CoA

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11 Six tubes containing preparations from animals were set up as shown below:

Tube Contents

1 Glucose + homogenised cells2 Glucose + mitochondria

3 Glucose + cytoplasm lacking organelles4 Pyruvic acid + homogenised cells5 Pyruvic acid + mitochondria6 Pyruvic acid + cytoplasm lacking organelles

After incubation, in which three tubes would carbon dioxide be produced?

A 1, 2 and 3

B 1, 4 and 5

C 2, 4 and 5

D 3, 5 and 6

12 When a glucose molecule is completely oxidised to carbon dioxide and water, 38 moles

of ATP molecules are formed. How many ATP molecules can be formed if a respiratory

poison such as cyanide is added to the oxidation process?

A 2 ATP

B 8 ATP

C 9 ATP

D 30 ATP

13 The following statements are related to the nutrition of living organisms

W- Photosynthetic bacteria synthesise organic food from carbon dioxide and water using

light energy absorbed by bacteriochlorophyll

X- Chemosynthetic bacteria use energy obtained from the oxidation of organic matter

Y- Human nutrition is holozoic nutrition

Z- Bacteria and fungi involved in decomposition are saprophytic organisms

Which of the above statements are true?

A W and Y

B Y and Z

C W, Y and Z

D X, Y and Z

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14 Graph 1 shows oxygen dissociation curves which illustrate the Bohr effect.

Which one of the following statements could represent the X factor?

I High pH

II Less CO2 partial pressure

III Smaller size of animals

IV Higher altitude

V Myoglobin

A I, II, IV and V

B I, III, IV and V

C II, III, IV and V

D I, II, III, IV and V

15 Which of the following is not a function of transpiration?

A Cooling of the leaf

B Excretion of mineral salts

C Transport of mineral salts

D Transport of water upwards

Percentage of saturation

P O2 mmHg

X

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16 Which nerve impulses can initiate normal expiration and prevent over expansion of the

lungs?

A Impulses from chemoreceptors in the lungs

B Impulses from stretch receptors in the diaphragm

C Impulses from the external intercostal muscles

D Impulses from the stretch receptors in the walls of the alveoli

17 Which one of the following is a function of the lymphatic system?

A To assist in the clotting mechanism of the blood

B To return tissue fluid to the bloodstream

C To transport dissolved food molecules to all cells of the body

D To transport hormones from endocrine glands to their target organs

18 What effect would be caused by cutting the sympathetic nerve fibres to the heart?

A A decrease in heart rate

B A decrease in the length of the diastole phase

C A decrease in the length of the systole phase

D A decrease in the stroke volume

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19 The passage of some of the contents of the plasma through the capillary wall depends on

the effective hydrostatic pressure (HP) of the blood in the capillary and the effective

osmotic pressure (OP) of the blood plasma. The diagram below shows the HP of the blood at the arteriole and venule ends of a capillary and the HP of the tissue fluid,

together with the OP of the blood plasma protein and the OP of the tissue fluids. All

pressures are in mm Hg.

Which one of the following is the pressure of filtration at the arteriole end of the capillary?

A 1mm Hg

B 9 mm Hg

C 15 mm Hg

D 25 mm Hg

OP = 25

HP = 32

OP = 25

HP = 12capillary

Tissue fluid

OP = 10

HP = 8

arteriolevenule

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20 The diagram below shows a nephron of the mammalian kidney.

Which one of the regions A, B, C or D is the main region responsible for restoring the

metabolite level of the blood plasma to its pre-renal level?

21 Thefollowing sequence of events occurs at the neuromuscular junction

Nerve Impulses Release ofV end plate potential Wproduced in muscle fibre

Xreleased from sarcoplasmic reticulum formation ofY Muscle contraction

Which one of the following shows the correct sequence from V to Y?

V W X Y

A Acetylcholine Action potential Calcium ions Actomyosin

B Acetylcholine Action potential Actomyosin Calcium ions

C Actomyosin Acetylcholine Calcium ions Action potential

D Calcium ions Action potential Actetylcholine Actomyosin

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22 Which statement is correct?

I Phytochrome is produced in the dark

II Phytochrome is a simple protein

III Phytochrome is a simple photoreceptor

IV Phytochrome is initially produced in an inactive form before it is converted into the

active form.

A I and II

B I and III

C III and IV

D II and III

23 The female oestrous cycle is controlled by the secretion and sequential release of at least

four hormones:

FSH-follicle stimulating hormone

LH-luteinising hormone

Oestrogen

Progesterone

Which one of the following shows the correct order in which they are released?

A FSH Oestrogen LH Progesterone

B FSH LH Progesterone Oestrogen

C Oestrogen FSH LH Progesterone

D FSH LH Oestrogen Progesterone

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24 Which one of the following chemical substances causes apical dominance in plants?

A Indole acetic acid

B Giberellic acid

C Cytokinine

D Abscissic acid

25 Which one of the following is true of T cells?

I T cells produce complement proteins

II T cells mature in the bone marrow

III T cytotoxic cells kill body cells that are infected with viruses

IV T suppressor cells inhibit the acivities of T cytotoxic cells

A I and II

B I and IV

C II and III

D III and IV

26 Which is not correct about the concept of self and non-self ?

A MHC protein markers on the surface of cells act as specific antigens

B Each organism carries a set of antigens which is unique to each individual

C In the embryo, T lymphocytes which can bind to the receptors (proteins and

polysaccharides) of their own body cells are induced to proliferate to form a clone of Tcells

D The immune system can distinguish self (the bodys own tissue) from non-self

(foreign tissue)

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27 Which one of the following represents the general pattern of the alternation of

generations?

A gametophyte meiosis sporophyte spores

B gametophyte meiosis spores sporophyte

C sporophyte meiosos gametophyte spores

D sporophyte meiosis spores gametophyte

28 If the diploid state is represented by (D) and the haploid state by (H), which one of the

following sequences correctly describes the chromosome number in the named plant structures?

Polar Nucleus Pollen grain Pollen tube nucleus Cell in the testa Cell in the pericarp

A (D) (D) (D) (D) (D)

B (D) (H) (H) (H) (H)

C (H) (D) (H) (H) (D)

D (H) (H) (H) (D) (D)

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29 Some seeds, in which the major food reserve is lipid, were analysed for lipid and sugar

content during germination in the dark. During germination, most of the lipid is converted

to sugar. The results of this experiment are shown in the graph below.

Which one of the following explains why the total sugar content decreases after one week?

A The rate of consumption of sugar in respiration suddenly increases

B Sugar is no longer being produced by photosynthesis

C The rate of consumption of sugar in metabolism exceeds the rate of production of sugar

from lipid

D The sugar has moved from the endosperm, where it was produced, to the embryo, where

it is needed

Lipid

Dry mass

lipid sugar

Time from sowing/ days0 12

Sugar dry

mass

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31 Drosophilia flies heterozygous for the size of the wing and body colour were crossed

with flies with vestigial wings and ebony bodies. The F1 offspring obtained were as

follows:

Normal wing, grey body: 522 Vestigial wing, grey body: 98

Normal wing, ebony body: 104

Vestigial wing, ebony body: 496

What is the crossover value?

A 8%

B 9%

C 17%

D 20%

32 Two animals are mated. One is homozygous dominant for one character and homozygousrecessive for another. The other animal is heterozygous for both characters. How many

phenotypes are expected in the offspring of this cross?

A 1

B 2

C 3

D 4

33 Two parents each of blood group A have a daughter of blood group O. What is the

probability that their next child will be a boy who has blood group O?

A 0.125

B 0.25

C 0.50

D 0.75

E 0.825

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34 Haemophilia is caused by a sex-linked, recessive allele. Two parents have a haemophiliac

son and a haemophiliac daughter.

What are the most likely genotypes of the parents?

mother father

A

B

C

D

XHX h

XHY h

XhX h

XHY H

XhY

XHY

XHY

XhY

35 During the formation of an ovum, non-disjunction of the sex chromosomes occurred. The

ovum was then fertilised by a normal Y bearing sperm cell. Which one of the following

shows the sex chromosome complement of the resulting zygote?

A XO

B XY

C XXY

D XXXY

E XXYY

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36 The diagram below shows an intergeneric cross performed in a breeding experiment

X plant Y plant

(2n=18) (2n=20)

Sterile hybrid Fertile hybrid

What is the chromosome number in the sterile hybrid and fertile hybrid?

Sterile hybrid Fertile hybrid

A 18 36

B 19 19

C 19 38

D 20 40

37 In a population of Africans, 1.0% of its individuals suffered from sickle-cell anaemia anddied. What is the percentage of the heterozygous individuals in that population that

possess abnormal haemoglobin?

A 1%

B 10%

C 18%

D 99%

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38 Which one of the following phenotypic features of Man can be affected only by

genotype?

A height

B intelligence

C skin colour

D number of different blood group antigens

39 The genotype and phenotype for a population of rabbits are as given below:

Genotype Phenotype Number of rabbitsR

MR

M

RM

RP

RPR

P

Black

Black, WhiteWhite

110

15048

The frequencies of allele RM

and RP

in this population are

RM

RP

A 0.4 0.6

B 0.3 0.7

C 0.2 0.8

D 0.6 0.4

40 Which one of the following statements is not true of the lactose operon?

A The lactose operon hypothesis was proposed by Jacob and Monod

B This system consists of four parts and they are the regulator gene, the promoter gene,

the terminator gene and the three structural genes

C This system is activated by the presence of lactose in the medium

D A repressor molecule bound to the operator gene will prevent the transcription

of the structural genes

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43 Which one of the following statements describes a feature of a natural system of

classification which an artificial system does not have?

A A natural system of classification is based on phenotypic characters.

B A natural system of classification is based on analogous structures.

C A natural system of classification is based on evolutionary relationships between

organisms.

D A natural system of classification is based on single characteristics rather than several

similar features.

44 Human blood when mixed with antibodies to human blood, will give maximum

precipitation. If another animals blood is mixed with antibodies to human blood, thepercentage of precipitation indicates how similarthe animal is to a human. The following

experimental results were obtained

Species: H 100%; M 37%; N 75%; O 79%; P 17%

Which phylogeny would fit these results?

H O N M P

A

H O N M P

B

CD

H M N O P H N M O P

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45 Refer to the following graphs which show the distribution of fang length in two

populations A and B of adult female wolf spiders that live in different environments. The

dotted line indicates the optimum fang length for capturing the most common prey in

each environment.

Which one of the following statements is consistent with the information shown in the

graphs?

A The average fang length in population A is greater than the average fang length in

population B

B The environment of population A has a wider range of prey than the environment of

population B

C The number of individuals in population A is the same as that in population B

D Population A would be more likely than population B to become extinct if the average

size of the prey in both environments decreased

46 Excess nitrate is a common pollutant in rivers and lakes causing rapid growth of

planktonic algae and the death of submerged plants rooted in the mud. Lack of whichfactor causes the death of the submerged plants?

A Carbon dioxide

B Light

C Organic debris

D Oxygen

Fang length (mm) Fang length (mm)

500 500

0.5 1.5 2.5 0.5 1 .5 2.5

Number of

individuals

Number of

individuals

Population A Population B

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47 Competition between species will be greatest if they try to occupy the same

A Community

B Ecosystem

C Habitat

D Niche

48 Humans affect the environment in the following ways

1 Felling of tropical rain forests

2 Harvesting of marine algae

3 Re-afforestation

4 Combustion of fossil fuels

5 Over-use of nitrate fertilisres

Which activities lead to an increase in the level of carbon dioxide in the earths atmosphere?

A 1, 2 and 3

B 1, 2 and 4

C 2, 3 and 4

D 2, 4 and 5

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49 The diagram represents a pyramid of energy which shows energy loss from a food chain

to decomposers, upward transfer of energy to the next trophic level and energy lossthrough repiration. All figures are in kJ, m

-, y

-1.

Loss to decomposers Total energy of trophic level Respiratory loss

24 16

114 206

1188 2052

11 880 20 880

What is illustrated by this diagram?

A A pyramid of energy shows the nutrient transfer less clearly than a pyramid of

numbers

B Energy loss to decomposers is higher than respiratory loss

C Food chain efficiency is about 10%

D The energy of the final trophic level is not used

40

360

3600

36 360 primary producers

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50 A student analyses the population of species X in an area S by using 1m X 1m quadrats

(as shown in the diagram below). The numbers in the quadrats represent the number of

species X. Calculate the density and frequency of species X

Density (m-2

) Frequency (%)

A 22.4 100

B 22.4 50

C 44.8 100

D 44.8 50

19 30 41

20

11

26

27

19

15

17

24

28

22

19

19

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PEPERIKSAAN PERCUBAANSIJIL TINGGI PERSEKOLAHAN MALAYSIA

NEGERI PAHANG DARUL MAKMUR

2009

BIOLOGYPAPER 2

Two and a half hours

Instruction to candidates:

DO NOT OPEN THIS QUESTION PAPER UNTIL YOUARE TOLD TO DO SO.

Answerallquestions in Section A. Write your answers in thespaces provided.

Answer anyfourquestions in Section B. Write your answerson your own answer sheets. Begin each answer on a freshsheet of paper. Answers should be illustrated by large andclearly labelled diagrams wherever suitable.

Answers may be written in either English or BahasaMalaysia.

Arrange your answers in numerical order and tie the answersheets to this question paper

This question paper consists of 11 printed pages

For examiners use

1

2

3

4

5

6

7

8

9

10

Total

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CONFIDENTIAL*

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This Question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*

2

Section A [ 40 marks ]

Answerall questions in this section.

1. The diagram below shows the DNA replication fork during DNA replication

(a) When does the replication occur in a cell cycle? [1 mark]

(b) Name enzymes C and D involved in replication and state their function.

[4 marks]

C : ..

Function : .

D : .

Function : .

(c) Based on the diagram, there are two newly synthesized strands, strand X and Y

(i) Name both strands and state the way they are synthesized. [2 marks]

X: ..

Y:

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3

(d) State why DNA replication is said to be semi-conservative. [1 mark]

..

..

(e) Explain why strand X is synthesized as fragments [2 marks]

..

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4

2. The diagram below shows changes in the membrane potential of a neurone during the pro-duction of an action potential

(a) Label phases A,B,C and the period labelled D as shown in the diagram. [4 marks]

A : ..

B : .

C : .

D : .

(b) Describe how A is maintained [2 marks]

..

(c) Distinguish between B and C [2 marks]

..

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5

.

(d) Why is the potential of D less than A? [1 mark]

..

..

(e) State the importance of D [1 mark]

.

.

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3. Graphs S and T show the measurements of growth of a same plant, Zea mays.

(a) Name the type of curve illustrated by graphs S and T. [2 marks]

S:

T:

(b) Explain what graphs S and T represent. [2 marks]

S: ..

T: ..

(c) Based on its lifespan, what type of plant is Zea mays known as? [1 mark]

..

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8

4. The figure below shows a summary of a procedure designed to clone genes

Foreign DNA Isolated plasmid

restriction

I

Recombinant DNA

II

Bacterial cell

III

SCREENING

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(a) What is meant by recombinant DNA? [1 mark]

.

(b) State briefly what happens at step I, II and III [3 marks]

I :

II:

III: .. r

(c) Why are the plasmid and foreign gene cut by using the same restriction enzyme?

[1 mark]

(d) State two ways in which bacteria can be screened for the presence of recombinantplasmids [ 2 marks]

..

..

..

(e) (i) State two benefits of insulin produced by genetic engineering [2 marks]

..

..

.

(ii) Unlike insulin, blood cannot be produced by genetic engineering.

Explain why ? [1 mark]

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10

Section B [60 marks]Answer anyfourquestions in this section.

5. (a) With reference to cellulose, explain briefly the term polymerization.State briefly the differences between the formation of polysaccharides and polypeptides

[7 marks]

(b) Describe the mechanism of action of an enzyme based on the induced fit model[8 marks]

.6. (a) State briefly the differences between anaerobic respiration that occur in plants and animals.

[6 marks]

(b) NAD and NADP are important molecules in plant cells. Describe in detail, the role ofthese molecules within a palisade mesophyll cell .

[9 marks]

7. (a) Drugs affect the nervous system by altering the mechanism of synaptic transmission.By using a suitable example, describe the effects of a stimulant drug on the nervoussystem.

[6 marks]

(b) AIDS is an immunodeficiency disease caused by an RNA virus.Describe how the virus replicates in the host cell .

[9 marks]

8. (a) Explain why no flowering response is shown by some plants that grow near highways.[5 marks]

(b) Explain the changes that occur during the onset of labour in humans.[10marks]

9. (a) With reference to an example, explain what is meant by the following genetic terms(i) multiple alleles(ii) polygenic inheritance

[6 marks]

(b) In sweet corn plants, the alleles for red and smooth seed are dominant over the alleles for

white and wrinkled seeds. Sweet corn plants with red and smooth seeds were crossed withplants with white and wrinkled seeds. A test cross was done using the F1 progeny and theresults are as follows:

Red, smooth 348White. wrinkled 335Red, wrinkled 40White, smooth 39

By using suitable symbols, draw a genetic cross diagram to explain the results.[9 marks]

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10. (a) Explain why proper management and conservation of ecosystems are needed.[5 marks]

(b) (i) Define sustainable development [2 marks]

(ii) Explain the benefits of sustainable development techniques used in the management offorests. [8 marks]

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1 A 11 B 21 A 31 C 41 B

2 B 12 A 22 C 32 B 42 D

3 D 13 C 23 A 33 A 43 C

4 A 14 A 24 A 34 A 44 B

5 C 15 B 25 D 35 C 45 B

6 C 16 D 26 C 36 C 46 B

7 D 17 B 27 D 37 C 47 D

8 B 18 D 28 D 38 D 48 B

9 A 19 B 29 C 39 D 49 C

10 D 20 B 30 B 40 B 50 A

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http://www.word-pdf-converter.com/http://www.word-pdf-converter.com/


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PEPERIKSAAN PERCUBAAN

SIJIL TINGGI PERSEKOLAHAN MALAYSIANEGERI PAHANG DARUL MAKMUR

2009

BIOLOGYPAPER 2

MARKING SCHEME

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1. (a) - during S phase / interphase 1 1

(b) - enzyme C : DNA polymerase 1

- function : adds complementary nucleotides to the growing strand 1

- enzyme D: DNA ligase 1

- function : links Okazaki fragments by forming phosphodiester 1 4bonds between the fragments

(c) - strand X : lagging strand, which is synthesized discontinuously 1- strand Y : leading strand, which is synthesized continuously 1 2

(d) - because each new DNA molecule contains one old and 1 1one new strand

(e) - the template for strand X is in the 5 to 3 end direction 1

- DNA polymerase only adds nucleotides at the 3 of a growing 1Strand

- therefore, strand X has to be synthesized away from replication fork 1

any 2 2

-------

total 10

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2 (a) A: Resting potential 1B: depolarization 1C: repolarisation 1D: refractory period 1 4

(b) - The active transport of sodium and potassium ions in 1and out across the membrane/ 3Na+ out, 2 K + in

- The membrane is more permeable to potassium ions 1compared to sodium ions ; thus more potassium ionsdiffuse out of the neurone compared to sodium ions diffuse in 2

(c)

B / depolarization C / Repolarisation

Sodium-gated channelsopen

Potassium-gated channesl open

Sodium ions enter the neu-rone

Potassium ions leave the neurone

The inside of a neuronebecomes positive

The inside of a neurone becomes negative

Any 2 pairs 2(d) - the potassium-gated channels remain open / slow to close 1 1

This allows further efflux of potassium ions

(e) - Limits the frequency in which impulses may flow 1- Ensures that impulses flow in one direction 1

along the nerveany 1 1

---------total 10

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3 (a) - graph S : absolute growth curve 1- graph T : absolute growth rate curve 1 2

(b) - graph S : actual increase in size / area/ growth over a period of time 1- graph T : the increase in size / area / growth per unit time over

a period of time 1 2

(c) - annual plant 1 1

(d) (i) - Limited growth 1- the growth curve is a sigmoid curve 1 2

(ii) - woody plants are perennial plants 1- display unlimited growth 1- the growth curve is a series of sigmoid curve 1 3

-----Total 10

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4 (a) - DNA that contains genes from more than one source 1 1

(b) - step I : Insertion of the DNA fragment into the plasmid 1

- step II : Transformation / introducing recombinant DNA into 1

host cell- step III: DNA cloning / amplification making multiple copies 1 3

of target gene

(c) - to produce the same sticky / blunt ends which are 1 1complementary to each other

(d) - cultured in a medium containing antibiotics/ ampicillin and X-gal 1 1before a blue-white screening

- hybridization by using genetics / radioactive probes 1 1

(e) (i) - insulin produced through genetic engineering is similar 1to human insulin

- insulin produced is non allergic 1- cheaper / not costly 1

Any 2 2

(ii) - because DNA / gene only codes for the synthesis of a 1 1protein and blood is not a protein

-----

Total 10

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5. (a)

answer marks

i. polymerization is formation of long repeated units of monomer 1

ii. by condensation with the removal of water molecules 1

iii. in cellulose the monomer unit is -glucose 1

iv -glucose linked together by - 1,4 glycosidic bonds 1

[any 3] maximum 3

Polysaccharide polypeptide marks

i. does not involve ribosome Involve ribosome 1/0

ii. only involve one type of monomer hexose molecule

Involve 20 different types of amino acid 1/0

iii. formation of glycosidic bonds betweenthe monomers

formation of peptide bonds between the mo-nomers

1/0

iv. does not involve gene / DNA Involve gene / DNA to code the amino acidsequences

1/0

v. does not involve mRNA and tRNA Involve mRNA and tRNA 1/0

vi. no transcription and translation stages Involves transcription and translation stages 1/0

[ Any 4 pairs] maximum 4

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(b)

Answer marksi. the active site of an enzyme is flexible 1

ii. and not exactly complementary / fitting to the shape of the substrate 1

iii. the active site of an enzyme can be modified when its interacts with substrate 1

iv. the active site changes its shape slightly as the substrate enters 1

v. the active site continues to change until the substrate is completely bound andfinal shape is determined

1

vi making the fit more precise 1

vii these structural changes may help to stabilized the transition state 1

viii. when the substrate binds to the enzyme, it forms an enzyme substrate complex 1

ix the substrate is then converted into products 1

x. the products are released from the active sites 1

xi, the enzymes return to its original conformation 1

xi. Products are released from the active sites 1

xii. the enzymes return to its original conformation 1

[any 8] maximum 8

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6. (a)

Plants Animals marks

i. occurs in roots / seed / storage organ/tuber

Occurs in skeletal muscles 1/0

ii. occurs when root are submerged //oxygen supply decreases

Occurs when muscles are activelyContracting

1/0

iii. products are ethanol and carbondioxide

Product is lactic acid 1/0

iv. pyruvate changed / reduced to ethanalfirst then to its final product, ethanol

Pyruvate directly changed / reduced to itsfinal product , lactic acid

1/0

v. ethanol is poisonous / can kill the plantcells Lactic acid is still useful / not poisonous 1/0

vi. ethanol cannot be converted back toglucose

Lactic acid can be converted back to glucose 1/0

vii. anaerobic respiration is not neededto sustain the supply of ATP

anaerobic respiration is useful to sustain thesupply of ATP

1/0

Any 6 pairs maximum 6

6 (b)

Answer

i. NAD involved in cellular respiration 1

ii. 2 molecules of reduced NAD / NADH produced in glycolysis 1

iii. 1 / 2 molecules of NADH produced in link reaction 1

iv. 3 / 6 molecules of NADH produced in Kreb cycle 1

v. NAD accepts hydrogen / electron and transfers / carry to the inner mitochondrialmembranes / cristae / cytochromes / ETC / matrix 1

vi. NADP involved in photosynthesis 1

vii NADP accept electron and hydrogen ion forming NADPH in non-cyclicphotophosphorylation / light dependent reaction / light reaction

1

viii. NADPH used in Calvin cycle / dark reaction / light independent reaction 1

ix. NADPH is used to reduce CO2 / in reduction phase 1

x. NADPH reduces glycerate -1,3-diphosphate into 1

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glyceraldehydes- 3-phosphate / PGAL[ Any 9] maximum 9

7. (a)

Answer

i. cocaine present in the synaptic cleft 1

ii. cocaine bind to the transporter molecules 1

iii. cocaine delays the breakdown of norepinephrine / dopamine / noradrenaline 1

iv. reuptake/reabsorption of the norepinephrine / dopamine / noradrenalin from syn-aptic cleft is prevented / blocked

1

v. norepinephrine / dopamine / noradrenalin remains / accumulates in thesynaptic cleft

1

vi. norepinephrine / dopamine / noradrenalin keep on binding to the receptors onthe post-synaptic membrane

1

vii. impulses will be generated repeatedly 1

viii. causes continuous euphoria / intense pleasure 1

[ Any 6] maximum 6

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8. (a)

answer marks

i. these types of plants are short day plants 1

The plants require a period of darkness equal to / longer than critical nightii. length

1

iii. light / spotlight flashes from vehicles interrupt / shorten the period of darkness 1

iv. causes the conversion of Pr into Pfr 1

v. Pfr is the (biological) active form 1

vi. high concentration / level of Pfr inhibit flowering in SDPs

[any 5]

1

Maximum 5

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(b) Explain the changes happens and action of hormone on the onset of labour in human

[10marks]

answer marks

i. estrogen level high in the end / last week of pregnancy 1

ii. stimulate the development of oxytocin receptor in uterine wall// increase the sensitivity of uterus muscle/myometrium to oxytocin

1

iii. babys head / growing fetus press against the mother cervix 1

vi. causing the cervix and uterine wall to stretch 1

v. thisstimulates maternal posterior pituitary to release oxytocin 1

vi. and also stimulates fetal pituitary gland secretes ACTH 1

vii. ACTH triggers fetal adrenal gland to secrete corticosteroids hormone 1

viii. corticosteroids hormone triggers placenta to secrete prostaglandin 1

ix. oxytocin also stimulates placenta / fetal to produce prostaglandin 1

x. both prostaglandin and oxytocin stimulates a powerful contraction ofmyometrium / uterus wall

1

xi. The more frequent the myometrium contracts, the more oxytocin/ prostaglandin produced

1

xii. the uterus contraction also stimulates stretch receptors in the uterine walland the cervix to trigger further release of oxytocin

1

xiii. the cervix dilates / widen, its tissue softens and become more flexible andamniotic bag burst

1

xiv. contractions become stronger and stronger / more frequent help to pushbaby down/out 1

(Any 10)

Maximum 10

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(b)

[9 marks]

Parents (p)

Phenotype Red smooth seed White wrinkled seedx

Genotypes

R R

S S

r r

s s

x

Meiosis

Gametes

R

S

r

s

Fertilisation

R r

S s

F1 generationgenotype

Phenotype All red and smooth seed

1

1

1

1

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Test cross for F1 progeny

]

R r

S s

r r

s s

xGenotype

Phenotype Red smooth seed White wrinkled seedx

R

S

r

s

R

s

r

S

r

s

Gametes

Recombinant/new

combination of genes

Genotypeoffspring

R r

S s

r r

s s

R r

s s

r r

S s

Red

smoothWhitewrinkled Redwrinkled Whitesmooth

Prentalcombination

Recombinants forms as aresult of crossing over

Phenotypes

346 335 40 39

1

1

1

1

1

1

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stpm trial 2009 bio q&a (pahang)

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