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CONFIDENTIAL*Name: ...................................... . Class: .......................................JABATMJABA TAl\ 964/2J A B A T A ~

'GERISEMBILAN JAGERISEMBILAN JA'GERISEMBILAN JA STPM 2011 'v1BILAN08/LAN'v1BILAN

JABA TAl\,

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Section A [40 marks]Answer all questions in this section.

]. The figure below shows a diagram of part of a polypeptide chain. This type ofstructure is commonly found in proteins.

X

a) Name the basic unit of a polypeptide chain. [1 mark]

b) Identify the type of bond in the structure labeled by the letter X. [1 mark]

c) (i) Name the level of the protein represented by the diagram. [1 mark]

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(ii) Describe the structure. [2 marks]

d) State what would happen to the polypeptide chain if it were healed to about70C

[ l mark]

e) Protein can be classified as fibrous or globular. Name one example of each.[2 marks]

f) Monosaccharides can also be linked together to form long chain moleculescalled polysaccharides. State two differences between a polypeptide and apolysaccharide chain. [2m arks

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2 The table below shows the percentage of saturation haemoglobin (Hb) resultingfrom a range of partial pressure of oxygen (PO:) at two different concentration of carbondioxide (mmHg)

P02 /mmHg %saturation ofHb at PC0 2 I % '"'"'"''"" ofHb"' PCO, I=40 mmHg = 80 mmHg10 ] ] 820 38 2230 59 4240 75 6050 83 7160 90 8170 94 88

f------- 80 98 95- 90 99 98

I 100 I 99 99

(a) Plot a graph on a single pair of axes to show these different cocentrationof carbon dioxide.

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[2 marks]

I

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_:_,'

-,--

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(b) From the graph, what is the percentage saturation ofHb when P0 2 is 55mmHg?

I. At Pco, 40 mmHg: ........................ .II . At Pco, 80 mmHg:

(c) What is your inference from the above answer?

(d) State two main features of the respiratory pigment, haemoglobin.

(e) Briefly explain the structure of erythrocyte in relation to its function.

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[1 mark)[1 mark]

[ I mark]

[2 marks]

[3 marks]

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3. The graph below shows the growth pattern in human organs and tissues.

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E0a:

20Clrl\

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(a) Name the type of growth pattern shown? Explain your answer.

(h) Name structures P, Q, RandS.

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[2 marks]

(4 marks]

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(c) Explain the relative grov,th of organs represented by P and S [4 marks]

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4. The diagram below shows the stages of meiosis during the formation of gameteswhich involve a pair of chromosome P and a pair of chromosome Q.

~ - ~ < I Meiosis IMeiosis II

LGameteS L GameteS Gamete T Gamete T

(a) What is the number of chromosome P if gametes S and Tare fertilized by normalgametes? [2 marks]GameteS: ...Gamete T : .......

(b) During the formation of gametes, the failure of sister chromatids or a pair ofhomologous chromosomes to separate causes a mutation which changes the numberof chromosomes.(i) Show the arrangement of chromosomes in the diagram if the process in (a) occurs

involving the pair of chromosome P during meiosis I. [6 marks]

(ii) Name the above phenomenon.

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[l mark]

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(c) State the type of the above chromosomal mutation.

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[1 mark]

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Section B [ 60 marks]Answer any four questions in this section

5 (a) Draw and label the structure of a cell membrane based on Singer's model.

6

7

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[3 marks](b) Explain the structures and functions of the cell membrane m th e

transportation of substances into the cell. [ 12 marks]

(aJ Describe the structure of phloem, [4 marks](b) What is meant by translocation? [2 marks](c) Using Mass flow hypothesis explain how organic substances are transported

in plants, [9 marks]

(a) What is meant by antibody and descr ibe its structure,(b) Explain humoral immunity,

(a) What is meant by:(i) Hardy-Weinberg's Law(iiJ Sickle cell anaemia

[5 marks][10 marks]

[3 marks][3 marks]

(b) In a particular country in Northern Africa, a medical study revealed that0,085% of the country's population are suffering from sickle cell anaemia,Sickle cell anaemia is controlled by a pair of alleles H and h, where theindividuals with the illness have the homozygous recessive genotype; thosewith normal red blood cell have the alternative genotype,

Using the Hardy- Weinberg's equation, calculate the percentage of thepopulation of the two genotypes for normal blood cells, [ 4 marks]

(c) In only a few remote areas in that country, the percentage of sickle cellanaemia reaches as high as 4%, Calculate:(i) the percentage of homozygous and heteroz\'gous individuals with the

normal blood cells, [3 marks](ii) the ratio for both the phenotype [2 marks]

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9 (a) Explain how amniocentesis is used in the screening for genetic defects.[6 marks]

(b) Explain the main steps in the formation ofDNA fingerprints and state the useof this technique. [9 marks]

10 (a) Explain biogeochemical cycle.(b) With the aid of a suitable diagram, explain the phosphorus cycle.

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[5 marks][1 0 marks]