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Candidate Centre Candidate
Name Number Number
2


GCE AS/A level
1071/01
BIOLOGY/HUMAN BIOLOGY ­ BY1
A.M. TUESDAY, 12 January 2010
1
1 /2 hours




For Examiner's use only




1
Maximum Mark
Question
Mark Awarded




W10 1071 01
1 6
2 6
3 11
4 11
5 12
6 14
7…

Page 2

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1. Two types of nucleic acid, DNA and RNA are found in cells. Statements in the table, may apply to
DNA, RNA or both. Complete the table by putting a tick () if the statement is true or a cross (×) if
the statement is not true.…

Page 3

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3. The diagram below shows a biosensor that uses the enzyme urease to measure urea in either the
blood or urine.



display



amplifier

transducer/electrode


ammonium ions
NH4+

immobilised urease
partially permeable membrane




3
molecules of
other solutes urea molecules




W10 1071 01
(a) (i) Name one method…

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(c) If the biosensor was used to test two blood samples, explain why the temperature of the two
samples should be the same. [2]

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(d) Name a medical condition which a biosensor can detect. [1]

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(Total 11 marks)


4. The drawing shows a…

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(c) Name the stage of mitosis where each of the following occurs.

(i) Chromatids line up at the equator. [1]

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(ii) Centromeres split. [1]

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(iii) Spindle fibres contract and shorten. [1]

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(iv) Chromosomes are first visible as a pair of chromatids. [1]

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(v)…

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5. The diagram shows cells taken from the stem of a plant. Cells A, B and C are adjacent cells and
the figures give the water potential of each cell.




A = ­ 400kPa
B = ­ 380kPa




C = ­ 360kPa




(a) (i) Draw arrows on…

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(i) Calculate the water potential, , of cell X. Show your working. [2]

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(ii) State the name of the condition shown by cell Y and explain how this condition could
have arisen. [3]

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(c) (i) Cell X has the higher…

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6. Heteropolysaccharides consist of long chains of monosaccharides. Each monosaccharide is
attached to a non-carbohydrate part.
Bacterial cell walls are made from a heteropolysaccharide consisting of two different
monosaccharides ­ abbreviated to NAG and NAM.
The linear polymer is made up of alternating NAG and NAM molecules,…

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(b) The diagram shows a molecule of the enzyme lysozyme.

20
Asn Tyr Arg Gly
Asp Tyr Ser
Leu Leu
Gly
Gly Asn
Trp
He Val 30
Cys
Glu Val Asp
Arg Ala Ala
Thr




S
120 Gly Ala
Trp




S
Lys Lys
Cys Lys
Met lle…

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(c) Catalase is an enzyme which breaks down hydrogen peroxide into water and oxygen.
Hydrogen peroxide is a highly toxic waste product of metabolism.
An investigation was carried out to determine the relative amounts of catalase in samples of
potato, liver and apple. The samples were ground…

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