SET 1 Answer

PERFECT SCORE BIOLOGY 2010

BAHAGIAN SEKOLAH BERASRAMA PENUH DAN SEKOLAH KLUSTER

KEMENTERIAN PELAJARAN MALAYSIA

PERFECTSCOREBIOLOGY 2010

MODULE Form 5

Teacher’s Copy

DISEDIAKAN OLEH:

1. Puan Hasimah binti Azit - Sekolah Seri Puteri, Cyberjaya2. Puan Tuan Norma binti Tuan Yaacob - SMS Alam Shah3. Encik Meli bin Hussin - SMS Kuala Terengganu

PAPER 2Section A

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Question 1:

Diagram 1 shows the human circulatory system.

(a) Human circulatory system consists of circulations R and S. Describe eachcirculation.

[4 marks] F1 Circulation R is pulmonary circulation E1 The deoxygenated blood is pumped into the lungs via pulmonary artery for gases exchanged E2 and the oxygenated blood back to the heart via pulmonary vein. F2 Circulation S is systemic circulation E1 the oxygenated blood is pumped to all parts of body cells via aorta. E2 After oxygen is supplied, the deoxygenated blood is transported back into the heart via vena cava.

(c) The pacemaker of a patient’s heart fails to function. An electronic pacemaker isused to replace the original pacemaker. Explain how the electronic pacemakerworks.

[3 marks] F1 It detects the heart’s own rhythms / initiates impulses F2 Impulses spread to both of the atria F3 Causing both of the atria contract simultaneously.

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Question 2:

Diagram 2 shows a longitudinal section of the reproductive parts of a flower during fertilization.

(a) In the space below, draw a section through the ovule showing all the cells in S. Label the cells involved in fertilization.

[3 marks]

Polar cell cell

Egg cell

Drawing: clear diagram with 8 nucleus - 1 mark Label : 2 label = 2mark

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(ii) Describe the fertilization process that occurs.

F1 One of the Q/ male nucleus fertilizes an egg to form the diploid zygoteF2 One of the Q/ male nucleus fertilizes 2 polar nuclei to form the triploidendosperm

[2 marks]

(c) In Diagram 2, the structure Y has to be kept dormant for future research purposes. (i) Explain how Y can be prevented from germinating.

F1 Keep Y in dry place/ low temperatureE1 because moisture initiate germination// enzyme is in inactive state

[2 marks]

(ii) If Y is to be germinated, suggest one method to stimulate the germination of Y

F1 Dropping/ spraying sucrose / sugary solution on Y

[1mark]

Question 3

Diagram 3 shows the prenatal development of a human embryo.

R

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(a) Explain how the adaptation of R in order to function effectively [3 marks]

F1 Consist of embryonic tissue that developed into plenty of small villi attached to endometrium, increasing the surface area for efficient absorption. F2 Network of blood capillaries in the placenta separated from the mother network capillaries in endometrium, prevent the foetal blood and the mother’s blood from mixing. F3 Blood capillaries of placenta and blood capillaries of foetus is much closed, enable the diffusion of digested food and waste product.

(b) If the mother is addicted to the drugs, does it possible for the baby to become addicted too? Explain your answer.

[2 marks] F1 Yes.E1 Drugs in the mother blood able to diffuse across the placenta into the baby blood, it is possible the baby to become addicted.

Question 4:

(a) Diagram 4.1 below show two types of variation in students,

Number of student

Body mass (kg)Blood group

Diagram 4.1

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Describe the differences between these two types of variation.

[3 marks]

F1 Blood group is discontinuous variation whereas the body mass is continuous variation. F2 The differences in type of blood is appears for a few discrete categories but body mass has no distinct categories. F3 Blood group is controlled by single gene and not influenced by environment but controlled by combined effect of many of genes and affected by environmental factors.

(b) Diagram 4.2 and diagram 4.3 show the changes occur in the structure of chromosomes which causes mutation.

P P P P

Q Q Q Q

R S R S

S T S R

T U T T

U U U

Diagram 4.2 Diagram 4.3

(i) State one factor which causes the mutation. [1mark]

F1 Mutagen (such as benzene, drugs, beta-ray)

(ii) Compare the changes of chromosome structure that causes mutations in Diagram 4.2 and Diagram 4.3

[4 marks]

F1 A segment in chromosome in Diagram 4.2 breaks off and lost but in Diagram 4.3 the segment breaks off but reattaches avertedly. F2 The mutation in Diagram 4.2 can causes lost of genes and can be lethal (dead) but mutation in Diagram 4.3 can causes changes in phenotype.

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Question 5:

An experiment is carried out to study the translocation of auxin in plants.

In experiment I, the coleoptiles tip was cut and placed on an agar block for 5 hours. This agar block X produced a growth curvature in another decapitated coleoptiles.

In experiment II, the coleoptiles tip was cut and placed in an inverted position on an agar block Y, for 5 hours. However no growth curvature was obtained when the agar block was placed on a decapacitated coleoptile.

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(a) Why does the coleoptiles in Experiment I bend to the right?

F1: The auxin from the agar block diffuses down to increase the rate of growth on

the left side E1: causing it to bend to the right.

[ 2 marks ] (b) (i) Name the plant hormone which causes the growth curvature.

F1 Indole acetic acid/auxin.

[ 1 mark ] (ii) Where is it synthesised in the stem?

F1 Tip of the stem. [ 1 mark ]

(c) Which agar block contains a higher auxin concentration? Give your reason

F1 X.E1 The agar block X produces a growth curvature indicating that auxin has diffused into one side of the coleoptile to increase the rate of growth. E2 The agar block Y produces no curvature indicating the absence of auxin in it.

[ 3 marks ]

(d) In which direction is this plant hormone transported in the coleoptiles? Give your reason

F1 From the tip of the coleoptile to its base.

E1 The presence of auxin in X and the absence of auxin in Y suggest that

translocation of auxin is from the tip to the base but not the reverse.

[ 2 marks ]


Question 6:

Figure below shows part of the circulatory system and the lymphatic system in the human body.

Vessel Q

heart

Tissuefluid

Body tissue

Fluid X

(a) ( i ) What is fluid X ?

F1 Lymphatic fluid

(1 mark )

(ii) What happens to the components of fluid X when it passes through the lymph

node?

F1 Fluid X was lack of lymphocytes whereas after lymph nodes more

lymphocytes.

(1 mark )

(b) ( i ) Fluid X originates from the blood.

Describe how fluid X is formed from the blood.

F1 When the fluid seeps through the blood capillaries into interstitial fluid,

E1 the pressure is higher in the interstitial fluid causes the fluid to be forced

into X.

( 2 marks )

( ii ) State one difference between fluid X and the blood.

F1 There is no red blood cells and plasma protein.

( 1 mark )

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Lymp node


(c) ( i ) A part of vessel Q is blocked.

Explain its effect on the system in figure above.

F1 If Q is blocked so the pressure in X will increase

E1 and causes the fluid to move back into the interstitial and accumulate in

the interstitial fluid.

( 2 marks )

( ii ) Vessel Q in the leg is blocked.

What would happen to the leg?

F1: swollen

( 1 marks )

(d) The blood circulatory system and the lymphatic system function to maintain the

composition of the tissue fluid.

Explain how water and mineral salts are maintained by?

F1 The blood circulatory system will maintain its contents such as water

and minerals salt by osmoregulation.

E1 The water and mineral salt is controlled by hormone from pituitary glands

and hence control the concentration of urine to be excreted by kidney.

E2 The lymphatic system uses the movement of muscle valve and the

pressure of the fluid to concentrate the water and mineral salt content.

( 3 marks )

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Question 7

Diagram 7 shows a ball and socket joint with tissues P, Q and which are responsible for locomotion in a human.

Diagram 7

(a) State the organelle found abundantly in the muscle cell.

F1 Mitochondria

[1 mark]

(b) Explain your answer in (a)

F1 Muscle cells are active cells E1 it needs lot of energy for the contraction of skeletal muscle

[2 marks]

(c) Name the muscle fibres that involve in the contraction of antagonistic muscle.

F Actins and myosin [2 marks]

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Question 8

(a) Diagram below shows two phenotypes of pea seed produced by two varieties of pea plant.

Smooth and Wrinkled andgreen pea seed yellow pea seed

A farmer has crossed a smooth and green pea plant with a wrinkled and yellow pea plant.

1600 pea seeds produced were collected and sorted according to different phenotypes as

shown in Table below.

Phenotype Smooth and Smooth and Wrinkled and Wrinkled and

green pea seed yellow pea green pea seed yellow pea

Number of

seeds 398 401 399 402

(a) State the ratio of the offspring produced.

1:1:1:1 [1 mark]

(b) (i) S represents the dominant allele for smooth while s for wrinkled. G is the

dominant allele for green and g ressesive allele for yellow. State the genotype of the

parents pea plant.

SsGg and ssgg

[2 marks]

State the probabilities of the alles in the gametes produced by the pea plants.

SG, Sg, sG and sg

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[2 marks]

(c) Based on your answer in b(ii), explain the formation of alleles in the gametes by

applying the Mandel’s Second Law

[3 marks]

F1 During gametes formation, each member of a pair of alles Ss may

combine

randomly with either member of another pair of alles Gg.

E1 During meiosis, only one of each pair of alleles Ss, and Gg can be present

in a single gamete.

E2 So alleles in gametes produced may be SG, sG, Sg and sg

(i) Draw a schematic diagram to show the product of this cross.

Parents: SsGg x ssgg

Gametes: SG : Sg : sG : sg all sg

Offspring: SsGg : SsGg : ssGg : ssgg

[3 marks]

(d)(i) A heterozygous plant genotype TtRr undergoes meiosis to produce gametes cell. Alleles

T and t for tall and short are located at the same locus on the homologous

chromosomes. During anaphase I, the alleles Tt are not separated but Rr are separated

completely.

Draw the diagram for the two gamete cells which will be formed in the space provided

below.

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[2marks]

(d)(ii) State the probabilities of the alleles in the gametes produced.

TtR, r or Ttr, R

[2 marks]

(d) The individual has three chromosome 21 due to non-disjunction during meiosis where

the two homologous chromosome 21 fail to separate normally during anaphase I or II

of meiosis.

State type of mutation faced by the individual.

Chromosomal mutation

[1 mark]

(e) Explain how mutation stated in (e) is formed.

F1 The number of chromosomes change during meiosis produced the

gametes cell has 24 chromosomes and the another one 22 chromosomes.

E1 An abnormal gamete 24 chromosomes fuses with the normal gamete

23 chromosomes

E2 produced zygote that has 47 chromosomes.

[3 marks]

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SET 1 Answer

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