Kelantan Schema Answer Paper 1 & 2

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4551 Biologi SEPT. 2008

PKPSM PEPERIKSAAN PERCUBAAN SPM TAHUN 2008

BIOLOGY PERATURAN PERMARKAHAN KERTAS 1,2, 3

UNTUK KEGUNAAN PEMERIKSA SAHAJA

Kertas soalan ini mengandungi 13 halaman bercetak.

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ANSWER PAPER 1 ;

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

C B C A C B A C C B A D B A A

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16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

D D D B D C B C A D A C D B B

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

C A D D C A B D C A D B C C B

46 47 48 49 50

D A A B B

BIO PAPER 1

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Diagram 1 shows structures of protein. The protein structures can be classified into four levels J, K, L and M based on organization of their structures. Rajah 1 menunjukkan struktur protein. Struktur protein boleh dikelaskan kepada empat aras J,K L dan M berdasarkan organisasi bentuk strukturnya.

X

Y J

K

L

M

Diagram 1 (a) ( i) Label amino acid and peptide bond in J Labelkan asid amino dan ikatan peptide pada J

1 (a)(i)

X : Amino acid Y : Peptide bond

[2 marks]

(ii) Name the protein structures of L and M Namakan struktur protein L dan M. 1 (a)(ii)

L: Secondary structure M: Quaternary structure

[2 marks]

(b) (i) Name the organelle in the cell where the protein is synthesized? Namakan organel dalam sel di mana protein disintesis? Ribosome

1 (b)(i)

[1 mark]

(ii) Name the process P in the following reaction? Namakan proses P dalam tindakbalas berikut? P + H2O

1 (b)(ii)

Hydrolysis 4551 ® 2008

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(iii) By using the letters J,K L and M, which protein structure is represented Dengan menggunakan huruf J, K, L dan M, struktur protein manakah mewakili Enzyme / enzim

:

K

Haemoglobin /hemoglobin

:

M

1 (b)(iii) [ 2 marks ]

All enzymes are protein. Enzymes are sensitive to temperature. Semua enzim adalah protein. Enzim peka kepada suhu.

(c) Explain why food is kept in refrigerator? Terangkan kenapa makanan disimpan dalam peti sejuk? F :

Temperature in refrigerator is low

P1 :

Enzyme (in bacteria) is inactive

P2 :

food cannot be decomposed [3 marks ]

d)

A branded washing machine is provided with temperature regulator. A housewife uses the detergent containing enzyme at 40oC to wash

1 (c)

the clothes. Using the information given, explain why? Mesin basuh berjenama

dibekalkan dengan pengawalatur suhu.

Seorang surirumah menggunakan pencuci yang mengandungi enzim pada suhu

40oC untuk mencuci pakaian. Dengan mengunakan

maklumat yang diberi, terangkan mengapa? F: 40oC is an optimum temperature P1: enzyme activity is maximum 1 (d)

P2: the cleaning is more effective. [ 2 marks]

TOTAL

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Diagram 2 shows a food pyramid. Rajah 2 menunjukkan piramid makanan.

DIAGRAM 2 Rajah 2 (a)

Label A, B, C and D are the different classes of food that make up the

2 (a)(i)

balanced diet. Label A, B, C and D adalah kelas-kelas makanan yang berbeza dalam gizi seimbang.

2 (a)(ii)

(i) Name the classes of food labeled C and D. Namakan kelas makanan dilabelkan C dan D. C : Fibre / roughage /dietary fibre D: Carbohydrate [2 marks] (ii) State two functions of C ? Nyatakan dua fungsi bagi C To prevent constipation // Source of vitamins // mineral (any example accepted) [2 marks] 4551 ® 2008

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Malnutrition caused by the unbalanced diet. Malnutrition of B for a long term will affects certain health problems. Malnutrisi berpunca dari gizi yang tidak seimbang. Malnutrisi bagi B dalam tempoh masa yang lama akan menyebabkan beberapa masalah kesihatan. (b)

Explain the statement above. Terangkan pernyataan di atas.. • Malnutrition due to the lacking , the excessive or the wrong proportion of nutrients intake for a long term. (1 mark) • Example of protein: bean/ meat/fish

(1 mark)

• Lack of protein intake cause kwashiorkor (1mark) • Health problem/ Symptom: scaly skin/ thin muscles/thin hair /swell of the body. (1 mark) OR • Excessive protein intake cause gout/ kidney stone/ kidney damage (1 mark)

2 (b)

• Health problem/ symptom :inflammation of joint /urination trouble [4 marks] Fermentation and UHT treatment are food processing methods. Penapaian dan UHT adalah kaedah pemprosesan makanan (c) Explain how the methods above extend the life span of the foods. Terangkan bagaimana kaedah-kaedah di atas dapat memanjangkan jangka hayat makanan. Method

Explanation /Biological concept

1 Fermentation

-Fermentation yields ethanol which, at high concentration, will stop the activity of Food substances are bacteria that cause food spoilage.(1 mark) added with yeast(1 mark)

2

UHT treatment Fresh milk is heated to 1320C for 1-5 seconds (under high pressure).(1 mark)

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The high temperature kills microorganisms/ bacteria /fungus and microorganisms/ bacteria /fungus spores. (1 mark)

2 (c)

TOTAL

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3 Diagram 3.1 shows agricultural activities which give effect P along the river at Zone R, Zone S and Zone T. Diagram 3.2 shows the changes of dissolved oxygen and the changes of certain bacteria population in the river. Rajah 3.1 shows aktiviti pertanian yang memberikan kesan P di sepanjang aliran sungai di Zon R, Zon S dan Zon T. Rajah 3.2 menunjukkan perubahan kepekatan oksigen terlarut dan perubahan populasi bakteria tertentu dalam sungai itu.

X

Diagram 3.1

Oxygen

S

T

Bacteria

Population of bacteria (arbitrary unit)

Concentration of dissolved oxygen. (arbitrary unit)

R

Diagram 3.2 4551 ® 2008

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(a) (i) What is the distance from X where the concentration of dissolved oxygen and the bacterial population begin to change?. Berapakah jarak dari X dimana kepekatan oksigen terlarut dan

3 (a)(i)

populasi bakteria mulai berubah?. 15 km [1 mark] (ii)

What is the ecological term for the effect P? Give one example of substance which cause the effect P. Apakah istilah ekologi bagi kesan P? Berikan satu contoh bahan yang menyumbangkan kesan P. Water pollution 3 (a)(ii)

Pesticide/ herbicide / fungicide/ insecticide OR Eutrophication Faeces / fertilizer’s [2 marks] (b) The fish population in the river was also affected by P.

Draw in the

Diagram 3.2 to show the change of fish population at Zone R, S and T. 3 (b)

Give a reason. Populasi ikan dalam sungai tersebut juga mengalami kesan dari P. Lakar graf dalam Diagram 3.2 untuk menunjukkan populasi ikan pada Zon R, S dan T. Berikan alasan anda. (On the Diagram 3.2) Oxygen level in the water drops, they die /

their population

decrease. [2 marks]

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After 3 years, there is abundant of algal population at Zone S which result the death of aquatic organisms. Selepas 3 tahun didapati Zon S mengalami pertumbuhan populasi alga yang sangat ketara dan menyebabkan kematian organisma akuatik. (c) Describe the phenomenon based on above statement. Berdasarkan pernyataan di atas, huraikan fenomena tersebut. o Agriculture activities releases fertilizer / nitrates / phosphates o Decomposition of the waste product/ sewage release mineral / ions o Leaching / Washing down the fertilizers and ions/minerals into the river, accelerate / promotes alga and aquatic plant growth/algal blooming o Prevent penetration of sunlight into the river and inhibit photosynthesis process 3 (c)

o Oxygen content decrease, aquatic organisms die. [4 marks] (d) Based on Diagram 3.2, explain the relationship among the agriculture sewage, bacterial population and the oxygen content in the river. o High agriculture sewage provides food / organic substances for microorganisms

3 (d)

o Encourages the population of bacterial in the river. o There is increase in oxygen consumption by the bacteria / High BOD o Therefore the oxygen content in the river decrease. [3 marks]

TOTAL

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4 Diagram 4 shows the pathway of water movement from the soil to the upper plant of the plant. Rajah 4 menunjukkan laluan

pergerakan air dari tanah ke bahagian atas

tumbuhan.

R

S

Soil

T

DIAGRAM 4 RAJAH 4 (a)

State one characteristic of R and its importance. Nyatakan satu ciri R dan kepentingannya o

Characteristics of R : small in size // have a large total surface area to volume (TSA/V) // Increases the surface area

o

Important of R: for water (and mineral) absorption //

o

Characteristics of R : Have thin cell wall // have no cuticle

o

Important of R: for water (and mineral) ions absorption //

o

Charateristics of R : The cell sap in R is usually hypertonic to the surrounding soil water.

o

4 (a)

Important of R: for water absorption. (any 2)

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[ 2 marks ]

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(b) (i) Based on Diagram 4, explain how water from soil move to structure T. Berdasarkan Rajah 4, terangkan bagaimana air dari tanah bergerak ke struktur T •

The cell sap of R is hypertonic to the soil water.

•

So, water diffuses into R by osmosis

•

The entry of water dilutes cell sap of R// cell sap of R becomes hypotonic compared to cell sap of S/ the next cells.

•

Therefore water diffuses into S/to these adjacent cells which become more diluted themselves, so osmosis continues across the S

•

The continuous flow of water in S creates a force known as root

4(b)(i)

pressure to push water into xylem. (any 4) (ii)

[ 4 marks ]

The flow of water along the T structure is carried out by capillary action. Name the forces involved to ensure the continuous flow of water. Pergerakan air sepanjang struktur T disebabkan oleh tindakan kapilari. Namakan daya yang terlibat untuk memastikan pergerakan air yang berterusan 4(b)(ii)

Adhesion & Cohesion (force) [ 1 mark ] (iii) Explain how these forces in b(ii) enables the movement of water to the top of the plant. Terangkan bagaimana daya dalam b(ii) membolehkan pergerakan air ke bahagian atas tumbuhan. o Adhesion – attraction force between water molecules and the xylem wall enable water to move up along the narrow xylem vessels o Cohesion – attraction force between water molecules form a

4(b)(iii)

continuous water column in the xylem vessels [ 2 marks ]

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(d) Describe how the plant control their water loss. Terangkan bagaimana tumbuhan mengawal kehilangan air. o

water is lost from the plant in the form of water vapour (into the surrounding air) by transpiration,

o

mainly through the stomata in the leaves.

o

The amount of water lost depends on the size of the stomatal pore

o

(the size of the stomatal pore) is controlled by the guard cell// through the opening and closing of stomata

OR Examples: in daylight /light intensity is high, the guard cell

4(d)

become turgid// stomata open, thus the water loss increases OR Examples: in dark /light intensity is low, the guard cell become flaccid// stomata closed, thus the water loss decreases TOTAL (any 3)

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[ 3 mark

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5 Diagram 5 shows the changes of four types of hormone which control the menstrual cycle and follicle development in the ovaries. Rajah 5 menunjukkan perubahan empat jenis hormon yang mengawal kitar haid dan perkembangan folikel dalam ovari.

P

Q

S

R

M

N

Diagram 5 (a) Based on Diagram 5 name the hormone labeled P and R. Berdasarkan Rajah 5, namakan hormon yang berlabel P and R: P : LH / Luteinising hormone

5 (a)

R : Oestrogen [2 marks] (b) Complete the follicle development in boxes M and N in the Diagram 5.

5(b)

Lengkapkan perkembangan folikel dalam petak M dan K pada Rajah 5.

[1 marks ]

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(c) Based on the Diagram 5, explain the relationship between the structure M and the level of hormone S. Terangkan hubungan di antara aras hormon S dengan struktur M. •

After ovulation, M / corpus luteum secretes S / progesterone

•

the level of S/ progesterone increases to maintain the thickness of the endometrium.

•

When the M / corpus luteum degenerates, the level of S/ progesterone decreases, the endometrium begin to disintegrates.

5(c)

[3 marks]

(d) If fertilization occurred, the level of hormones S is maintained and the pregnancy is proceed. Explain the importance of hormone S. Jika persenyawaan telah berlaku, aras hormone S dikekalkan dan kehamilan terus berlaku. •

To inhibit the secretion of FSH and LH from pituitary gland

•

No development of follicle / secondary oocyte

•

Then the secretion of oestrogen is reduced

•

Repair/ rejuvenation of endometrium is not happened

•

Hence no new early embryo develops.

5(d) [3 marks]

(e) If the sperm counts of a husband is too low, artificial insemination can be carried out to overcome this infertility problem. Discuss the appropriate technique should be used. Jika jumlah sperma suami terlalu rendah, teknik permanian beradas boleh digunakan untuk mengatasi masalah ketidaksuburan ini. Bincangkan

5(e)

teknik yang sesuai digunakan. •

The sperms are collected from the husband / taken from sperm banks.

•

And inserted directly into the Fallopian tube of the wife during TOTAL

ovulation phase. [2 marks] 4551 ® 2008

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17 Section B [ 40 marks ] Answer any two question. The time suggested to complete this section is 60 minutes

6

(a)

According to the stages metaphase, anaphase and telophase in cell division, differentiate the events happening during mitosis and meiosis. Berdasarkan

kepada

peringkat

metafasa,

anafasa

dan

telofasa

dalam

pembahagian sel, bezakan peristiwa yang berlaku semasa mitosis dan meiosis. [4 marks] (b)

Diagram 6.1

Diagram 6.2

Diagram 6.1 is a new variety of a vegetable which has a great commercial value. Diagram 6.2 is the original parent of the plant. Based on above Diagram and with your biological knowledge, explain how a farmer can propagate this variety to give a large scale of yield and at the same time maintains its quality. Rajah 6.1 adalah satu variati sayuran di mana mempunyai nilai komersial. Rajah 6.2 adalah induk tempatan pokok tersebut. Berdasarkan Rajah di atas dan pengetahuan biologi anda, terangkan bagaimana seorang petani dapat memperbanyakkan variati ini supaya hasil ladang dapat meningkat dan pada masa yang sama, kualiti dapat dipelihara. [6 marks] c) Discuss how mutation can lead to the formation of tumour Bincangkan bagaimana mutasi dapat menyebabkan pembentukan tumor. [10 marks]

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Diagram 7 shows the colour variation in a species of moth, Biston betularia in polluted environment. Due to natural selection, the white coloured moth’s become extinct as well as the time passed. Rajah 7 menunjukkan

variasi warna bagi satu spesis kupu-kupu di suatu kawasan

persekitaran tercemar.

Akibat dari pemilihan semulajadi, lama-kelamaan kupu-kupu

putih mengalami kepupusan.

Diagram 7 / Rajah 7

(a) Based on the Diagram 7 , explain the meaning of ‘natural selection’. Berdasarkan Rajah 7, terangkan pengertian ‘pemilihan semulajadi’ [4 marks] (b) The variation of human blood group is determined by three different alleles A, B and O. By using a schematic diagram, show the possibilities of phenotypes and genotypes of the offsprings if mother’s blood group is AB and father’s blood group is A. Variasi kumpulan darah manusia ditentukan oleh tiga alel yang berbeza A, B dan O. Dengan mengunakan rajah skema, tunjukkan kemungkinan fenotip dan genotip anak-anak jika kumpulan darah ibu AB dan kumpulan darah bapa adalah A. [6 marks ] (c)

Table 7.1 and 7.2 below show the blood group and height variations of the students in a secondary school. Jadual 7.1 dan 7.2 di bawah menunjukkan variasi kumpulan darah dan ketinggian pelajar di sebuah sekolah menengah.

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i) Blood Group / Kumpulan darah Blood group Kumpulan darah

B

A

Number of students Bilangan pelajar

13

AB

9

0

3

20

TABLE 7.1 JADUAL 7.1 ii) Height / Ketinggian Height / Tinggi

135139

140144

145149

150154

155159

160164

165169

170174

2

5

7

9

10

7

4

1

( cm ) Number of students Bilangan pelajar

TABLE 7.1 JADUAL 7.1 Based on Table 7.1 and 7.2, construct two different histograms on a graph paper to show the number of students against blood group and the number of students against height. Explain the similarities and differences between these two types of variations. Berdasarkan Jadual 7.1 dan 7.2, bina dua histogram yang berbeza pada satu kertas graf untuk menunjukkan bilangan pelajar melawan kumpulan darah dan bilangan pelajar melawan ketinggian. Terangkan persamaan dan perbezaan antara dua jenis variasi tersebut. [10 marks]

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SUGGESTED ANSWER : No.

ACCEPTED POINTS / DESCRIPTION / EXPLANATION

6(a)

o

Able to differentiate the events happening during mitosis

M

Sum

4

and meiosis.

Stages 1. Metaphase

Mitosis

Meiosis

- homologous chromosome are - homologous chromosome line up arranged /randomly

in linear sequence side by side at the metaphase plate at

the

metaphase

plate 2. Anaphase

- separation of sister chromatids

- separation of the homologous

to the opposite pole// the

chromosome to the opposite pole //

centromere of each chromosome

sister chromatids still remain

divides into two and allows sister

attached to each other during

chromatid to move to opposite

movement to the opposite pole

pole. 3. Telophase

- two daughter nuclei are formed - four daughter nuclei are formed - diploid (2n) number of chromosome is remained

- diploid (2n) number of chromosome is reduced to haploid (n) - daughter cells are differ

- daughter cells are genetically identical to each other and to

from the parent and from each other// variation

the parent cell. occurs among daughter cells.

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6(b)

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ACCEPTED POINTS / DESCRIPTION / EXPLANATION

M

Sum

Able to explain how a farmer can propagate this variety to give a large scale of yield and at the same time maintains its quality. 1

• The technique used is tissue culture technique • A piece of tissue/explant is taken from the young part of the

1

parent plant eg. Shoot/ root and cut into smaller pieces • The tissues are sterilized (with dilute sodium hypochlorite solution) to prevent the growth of pathogens / bacteria

1

/fungus. • Each pieces of sterilised tissue is placed onto a growth medium/

gel containing

1

nutrients (eg. Glucose, amino

acid, minerals etc.) and hormone/auxin with optimum

pH

level • The apparatus and culture medium used must be in sterile

1 1 point 1 mark

conditions and kept under the suitable temperature/ 3035°C. • The tissue cells then divide repeatedly

by mitosis to

produce a mass of undifferentiated cells/ callus • After several weeks, callus differentiated to produce shoots

1 1

and roots /organogenesis. • Once the roots grow, the plantlets/little plant are removed

10 point 10 marks Max: 6 marks

Max 1

6

and transferred to the soil for growth into the adult plant. • All the plantlets produced this way are genetically identical

1

and known as clones. • Therefore, all adults plants that develop from them share

1

the same traits, for example has large fruits. 4551 ® 2008

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6(b)

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ACCEPTED POINTS / DESCRIPTION / EXPLANATION

M

Sum

Discuss how mutation can lead to the formation of

• certain substance/carcinogen such as benzo - A - 1 pyrene etc… • can cause the change in DNA structure (that control 1

the cell cycle) • an abnormal cell is formed/ cancer cell / mutant cell • this change disrupts the coded DNA genetic instruction for mitosis control

1 1

• this leads to uncontrolled mitosis (which is non-stop division of the cell) producing a mass of new daughter 1 cells called tumour • tumour cells have no function, but instead compete with surrounding normal cells to obtain nutrients and 1 energy for their own growth • some tumours remain inactive and are relatively harmless (not cancerous) and called benign tumour

1

• Benign tumour cells remain at its original site and do 1 not spread to other part of the body. It can be removed by surgery. • Other tumour, called malignant tumours are very active (cancerous), spread locally and some cancer 1 cell migrates

through bloodstream to invade other

organ. • when this happens, secondary tumous develop in

1

other body tissue, then lead to the malfunction of the tissue and ultimately death • An individual with a malignant tumour is said to have 1 cancer. 4551 ® 2008

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QUESTION 7 No. 7a

ACCEPTED POINTS / DESCRIPTION / EXPLANATION

M

Sum

Able to explain the meaning of natural selection. • Over the time, one species better adapted to the environmental

1

changing. • Example : camouflage of colour protect themselves from predator

1

• That particular ( white/ black) species increase their population

1

while the others cannot.

[4 marks]

1

• White species / black species becomes dominant in their community 7b

Enable to draw a schematic diagram Parents

Mother Group AB

Genotypes

Max 6 Father Group A …………….. 1m

X

AB

AA

…………...1m Meiosis 1m

Gamets

A

B

A

A

………1m Fertilization 1m

Children’s genotypes AA

AA

AB

AB

………..1m

Children’s phenotypes A

A

AB

AB

…………1m

# 50% of the children have group A and 50% of the children have group AB .1m [Max 6/ 8 ] OR

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Absorptio n Serapan

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ACCEPTED POINTS / DESCRIPTION / EXPLANATION Parents

Mother Group AB

Genotypes Gamets

7(c)

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Sum

Father Group A

AB A

M

AO B

Children’s genotypes AA

AO

Children’s phenotypes A

A

A

O

AB

BO

AB

B

# 50% of the children have group A , 25% of the children have group AB and 25% of the children have group B. [ max 6 / 8 mark] Graph: Height variation – continuous 4 marks Blood group Variation – discontinuous Able to explain the similarity and contrast of height variation and blood group variation. 1m

# Similarity – both height variation and blood group variation create varieties in population. # differences Height

5m Blood group

1. Continuous variation

Discontinuous variation

2. Graph shows normal distribution

Graph shows discrete distribution

3. influence by environmental factors

Influence by genetic

4. Traits are controlled by two or more genes

Traits are controlled by a single gene

5 The phenotype is usually controlled by many pairs of gene.

The phenotypes is controlled by a pair of alleles.

6. the characters can be measured and graded // quantitative

The characters cannot be measured and graded // qualitative.

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25 Section B [ 40 marks ] Answer any two question. The time suggested to complete this section is 60 minutes

8 (a) Diagram 8 shows the schematic diagram the regulatory mechanism of carbon dioxide content in the human body. Rajah 8 menunjukkan rajah skema mekanisme kawalatur kandungan karbon dioksida dalam badan manusia. Detected by Dikesan oleh

Nerves Impuls Impuls

Nerves Impuls Impuls

Carbon dioxide level in the blood increases Aras karbon dioksida dalam darah meningkat

Detected by Dikesan oleh

DIAGRAM 8 RAJAH 8 (a) Based on Diagram 8, explain how the regulatory mechanism of carbon dioxide assists a person during vigorous activity to maintain the carbon dioxide content in his blood. [10 marks] Berdasarkan Rajah 8 terangkan bagaimana mekanisme kawal atur kandungan karbon dioksida

membantu seseorang yang melakukan aktiviti cergas menstabilkan

kandungan karbon dioksida dalam darahnya. [10 markah] 4551 ® 2008

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(b) Some families often eat fast food because working parents do not have time to prepare home cooked food. These eating habits lead to many health problems. Sesetengah keluarga kerap mengambil makanan segera kerana ibubapa mereka yang bekerja tidak mempunyai masa untuk menyediakan sarapan di rumah. Tabiat makan ini menyebabkan berlakunya pelbagai masalah kesihatan.

You are asked to prepare a talk on” Good eating habits” for a group of parents. Discuss the good eating habits that you may want to educate them. Anda dikehendaki menyediakan suatu ceramah yang bertajuk “ Amalan tabiat pemakanan yang baik” untuk sekumpulan ibu bapa. Bincangkan amalan pemakanan yang baik untuk disampaikan kepada mereka. [ 10 marks]

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9 (a)

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27 Diagram 9 shows the Nitrogen Cycle. Rajah 9 menunjukkan kitar Nitrogen. Nitrogen in the atmosphere Nitrogen dalam atmosfera

Faeces Najis Root nodules of legumes Nodul akar kekacang

Urine Air kencing

Organic materials Bahan organik

Ammonium compound Sebatian ammonium

Nitrite Nitrit

Nitrate Nitrat Diagram 9.1 Based on Diagram 9.1, discuss the role of microorganisms in the Nitrogen Cycle. Berdasarkan Rajah 9.1 , bincangkan peranan mikroorganisma di dalam Kitar Nitrogen [10 marks] 4551 ® 2008

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(b)

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Diagram 9.2 shows the ozone layer in atmosphere that protects earth from ultraviolet rays from the sun. Rajah 9.2 menunjukkan lapisan ozon dalam atmosfera yang melindungi bumi daripada sinar ultraviolet daripada matahari.

Solar radiation Sinaran suria

Stratosphere Stratosfera Absorption Serapan Ozone layer Lapisan ozon Harmful ultraviolet radiation Sinaran ultra ungu berbahaya Troposphere Trofosfera

Earth Bumi DIAGRAM 9.2 Describe how the ozone layer becomes thinner. Discuss its effects on humans and the environment and suggest the ways to solve these problems. Huraikan bagaimana lapisan ozon menjadi semakin nipis. Bincangkan kesannya kepada manusia serta alam sekitar dan cadangkan langkah-langkah untuk mengatasi masalah ini. [10 marks]

END OF QUESTION PAPER 4551 ® 2008

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SUGGESTED ANSWER : No.

ACCEPTED POINTS / DESCRIPTION / EXPLANATION

6(a)

o

Able to differentiate the events happening during mitosis

M

Sum

4

and meiosis.

Stages 1. Metaphase

Mitosis

Meiosis

- homologous chromosome are - homologous chromosome line up arranged /randomly

in linear sequence side by side at the metaphase plate at

the

metaphase

plate 2. Anaphase

- separation of sister chromatids

- separation of the homologous

to the opposite pole// the

chromosome to the opposite pole //

centromere of each chromosome

sister chromatids still remain

divides into two and allows sister

attached to each other during

chromatid to move to opposite

movement to the opposite pole

pole. 3. Telophase

- two daughter nuclei are formed - four daughter nuclei are formed - diploid (2n) number of chromosome is remained

- diploid (2n) number of chromosome is reduced to haploid (n) - daughter cells are differ

- daughter cells are genetically identical to each other and to

from the parent and from each other// variation

the parent cell. occurs among daughter cells.

1m each = max 4 marks

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ACCEPTED POINTS / DESCRIPTION / EXPLANATION

M

Sum

Able to explain how the regulatory mechanism of carbon dioxide content in the human body. 1. Vigorous exercise produces more carbon dioxide/ the carbon dioxide content increase as a result of active cellular respiration

1

2. Carbon dioxide dissolved in the plasma to form carbonic acids // CO2 + H2O H+ + HCO3-

1

3. Carbonic acids converted into bicarbonate ion and hidrogen ion.

1

4. Concentration hidrogen ion increased// drop in pH value of blood (and cerebrospinal fluid)

1

5. The drop in pH is detected by Central Chemoreceptor in Medulla Oblongata

1

6.

(also) detected by peripheral chemoreceptor / carotid bodies / aortic bodies.

7. Chemoreceptor (Central and peripheral ) triggers nerve impulse and sends to medulla oblongata 8. Then the Central Chemoreceptor send the nerve impulses to the diaphragm and intercostal muscle in the lung

1 1 1 1

9. Causing (respiratory muscles) to contract and relax, Finally increases the breathing and ventilation rate

1 10 As excess CO2 eliminated from the the body, carbon dioxide concentration and pH value of blood return to normal 11. (also) the Central Chemoreceptor send the nerve impulses to cardiac muscle 12. Cardiac muscles contract and relax faster// Heart beat increased 13. Blood transport more O2 to tissue/ body cell for cell

1 1 1

respiration ( to produced energy)// more CO2 can be 4551 ® 2008

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No.

ACCEPTED POINTS / DESCRIPTION / EXPLANATION

M

Sum

transported to the lung (to eliminated from the body) 14. Carbon dioxide concentration and pH value of blood return to normal levels

1 Max 9

Maks: 9 markah KA – P5,P7,P9 & P11 – 1m Jumlah: 10 markah 8b

1 10

Able to discuss the good eating habits o

Good eating habits mean taking food in the correct quantity

1

at the correct time o

Also should refrain from overeating or eating too little during

1

a meal o

Improper eating habits can lead health problems

1

Example Health problems related to eating habits o

obesity is caused by consumption of excess energy rich

1

food such as liked carbohydrates and fats o

and by lack of exercise

1

o

Diabetes mellitus is caused by overeating of sweet foods.

1

o

Gastritis is caused by inflammation and erosion of the stomach/ by drugs such as aspirin or by drinking high

1

concentration of alcohol/ due to poor diet/ irregular food intake some of the good eating habits that we need to inculcate are o

always eat a balanced diet that include all the different classes of food / protein, carbohydrate, fat, vitamins,

1

minerals, water and fibre o

in right

quantities and in correct proportions

o

always refer to the Food Guide Pyramid. Choose from four

1

level of food -

Level 1 – bread, cereals, rice, pasta group (eat most / 50 % from the energy value)

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No.

ACCEPTED POINTS / DESCRIPTION / EXPLANATION -

Level 2 – fruits and vegetables

-

Leve 3 – meat, fish, eggs, nuts, poultry, milk, yogurt

M

Sum

and cheese -

Level 4- Lipids, oils and sweets group (eat less)

1 o

Take proper meals a regular times of the day / in three meals a day

o

involve choosing the types of food we eat wisely/aware of the

1 1

contents of the food that consume every day o

check the food labels for information regarding the nutrient

1

contents/ the total calories of the food o

also check the freshness and various safety aspects

1

o

for example whether the food contains additives which effects

1

on health o

avoid consuming unhealthy food / junk foods, salty snack foods,

1

because junk food includes food that is high in salt/sugar/fat but

1

low in nutritional value

1

o

avoid taking excessive fatty food and food rich in sugar.

o

avoid overeating, it will lead to obesity

o

avoid under eating, it cause tiredness, malnourishment

o

and may lead to health problem like anorexia nervosa and

1 1 1

bulimia o

avoid eating too fast and eat slowly.

o

Take time to chew the food

o

avoid smoking, drinking too much alcohol and coffee

to avoid indigestion

1

Max: 10

1 1

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Item Criteria number F1 - Rhizobium bacteria inside the root nodules 9 (a) of legumes and Nostoc sp. found freely in the soil fixed the nitrogen in air

Marks

Notes

1

F2 - decaying bacteria / fungi decompose plant /animal / dead organism / waste product

1

P1 - to form ammonium compound

1

F3 - Nitrosomonas sp./ nitrifying bacteria converted ammonium compound to nitrite

1

F4 - Nitrobacter sp /nitrifying bacteria convert nitrite to nitrate

1

P2 - nitrate is absorbed by plant to form plant protein

1

P3 - (plant protein) eaten by an animal to form animal protein

1

F4 - Denitrifying bacteria reduce the nitrate content in the soil

1

P4 - by converting the nitrate into nitric oxide and nitrogen gas

1

P5 - nitrogen gas goes back into the atmospheric to complete the nitrogen cycle

1

10 mark s

Able to explain how the ozone layer becomes 9 (b)

thinner / ozone depletion occur • Thinning of the ozone layer is due to the

1

widespread use of CFC • It is used in aerosol, industrial solvents, electronics and Freon in air conditioners

1

• Ultraviolet radiation strikes a CFC molecule cause the chlorine atom to break away

1

• Then the chlorine atom collides with an ozone molecule and combines with an oxygen atom to

1

form chlorine monoxide and oxygen 4551 ® 2008

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Item number

Criteria • Then the free atom of oxygen collides with the

Marks

Notes

1

chlorine monoxide, the two oxygen atoms form a molecule of oxygen

1

Max 5

• The chlorine atom is released and free to destroy more ozone molecules

1

• The chlorine produced re-enters the cycle • When the ozone layer becomes thinner, more ultraviolet radiation reaches the Earth

1

The effect of excessive ultraviolet radiation on human • reduction of the body’s immune system

1

• skin cancer

1

• cataract of the eye

1

Effect on plants

Max 3

• reduction of the rate of growth therefore reducing 1

crop yields Effect on aquatic organism • death of plankton, reduce food supply to aquatic organism, fisherman’s catch is reduced.

1

Max 2

Steps to overcome this problem • Reduce or stop using CFC or chlorine-based products • Replace CFC with HCFC • Use wrapping papers instead of polystyrene boxes • Patch up the holes in the ozone layer by firing frozen ozone balls into the atmosphere

1 1 1 1 TOTAL 10marks

END OF MARKING SCHEME 4551 ® 2008

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