2010 a Level h2 Biology Dunman High

7/26/2019 2010 a Level h2 Biology Dunman High

1/46

_ N _ a _ m _ e _ _ _ ~ I

_, _ J I

~ ~

BIOLOGY

DUNMAN HIGH SCHOOL

SENIOR HIGH

2010 PRELIMINARY

EXAMINATIONS

General Certificate of Education Advanced ,

Level

YEAR SIX H2

BIOLOGY (9648)

9648 01

PAPER 1 Multiple Choice

28

September

1

Tuesday

1 hour 15 minutes

Additional Materials: Multiple Choice Answer Sheet

READ THESE INSTRUCTIONS FIRST

Write in soft pencil.

Do not use staples, paper clips, highlighters , glue or correction fluid.

Write your name, civics group and index number on the Answer Sheet in the spaces provided

unless this has been done for you.

There are forty questions

in

this paper. Answer all questions. For

each

question there are four

possible answers,

A,

8, C and D.

Choose the one you consider correct

and

record your choice

in the soft

pencil on separate

Answer Sheet [optical answer sheet (OTAS)] provided.

Read the Instructions on the Answer Sheet very carefully.

Each correct answer will score one

mark.

A mark will not

be

deducted for a

wrong

answer. Any

rough working should be done in this booklet.

Calculators may be used.

Do not open this booklet until you are told to do so.

This question paper consists of

1l

printed pages

and

1blank pages. (including this cover page)

[ urn over

Multiple Choice Questions

40

marks

Answer

all

questions.

Which of the following statements is TRUE regarding the polysaccharides starch,

glycogen, cellulose, and chitin?

A All have a,

1-- 4

linkages.

B Starch is built from a different monomer than are the others .

C Each is built from a single type

of

monomer.

D

Chitin and cellulose differ from each other only in the

extent of

their branching.

2 All

of

the following statements about the fluid mosaic model

of

biolpgical

meffil?ranes are true EXCEPT ,

A Lipid molecules in the membrane readily undergo lateral diffusio n.

8 Lipid molecules in the membrane readily undergo transverse (flip-flop) diffusion

C Integral membrane proteins can undergo lateral diffusion

D The transition temperature

of

a membrane is sensitive

to

the composition

of

the lipid molecules in the membrane .

3 Membrane carrier proteins differ from membrane channel proteins by which

of

the

following characteristics?

A Carrier

p r o t ~ i n s

are glycoproteins , while channel proteins are lipoproteins.

B

Carrier proteins can mediale active transport, while channel proteins cannot.

C Carrier proteins do not bind

to

the material transported, while channel proteins

do.

D Carrier proteins transport molecules down their electrochemical gradient, while

channel proteins transport molecules against their electrochemical gradient.


2/46

Drugs that either stabilize or depolymerize microtubules can be used in cancer

chemotherapy.

Which

o

the following

is

correct concerning such drugs?

A They prevent movement

o

tumor cells into other tissues.

B They prevent chromatin condensation.

C They interfere with endocytosis.

D

They interfere with mitosis .

5

In

an investigation to determine the effect of temperature on the activity of

an

enzyme, the time

or all

the substrate to disappear from a standard solution was

recorded.

Which graph shows

the

results of this investigation?

A

B

t i m ~ ~

temperature temperature

c

D

time

t ml

temperature temperature

6 When DNA replicates semi-conservatively, enzymes are used separa te

the

DNA

double helix and

to

synthesize the new strands.

Which

o the

following

EST

describe the functions of the enzymes involve in this

process?

unwinding of the

assembly of the

filling in of gaps fusing together of

DNA molecules

leading strand between new new DNA

DNA fragments fragments

A

polymerase ligase polymerase helicase

8

helicase polymerase polymerase

ligase

c

ligase polymerase helicase polymerase

D helicase

polymerase

ligase

polymerase

7 Which of the following statements about RNA is CORRECT

i) Hydrogen bonds between bases temporaril y hold RNA against mRNA.

(ii) The base sequences in the RNA molecules are the same

as

the base

sequences in the DNA that is being translated .

(iii) RNA translates the base sequence

in

DNA into

the

amino acid sequence

in a protein.

(iv) The specificity of a RN A molecule depends

on

the specificity

o

the

enzyme that loads it with an amino acid.

A i)

, ii)

and

(iii)

B (i), (iii)

and

iv)

c (ii), (iii)

and iv)

D All of the above .


3/46

8 The table shows the mRNA codons for

11

di fferent amino acids.

amino acid

mRNA codon

am

ino

acid

mRNA

codon

Ala GCG

Val

GUG

Glu

GAG

Phe uu

Gly

GGA

Lv

s

AAG

His

CAC

Thr ACU

Arq

CGC

Pro u

Leu

CUG

ue

The first seven DNA triplets coding for a protein are shown belo w. These are

DN

A

triplets from the coding strand complementary to the mRNA.

CACGAGGCGAAGGGACACCGC

The mutation occurs when the tenth nucleotide in the DNA sequence is changed to

a G What is the amino acid sequence for the mutated section of DNA?

A His Glu Ala Lys Gly His Arg

B His Glu Ala Glu Gly His Arg

C Val Leu Arg Leu Pro Val Ala

D Val Leu Arg Phe Pro Val Ala

9 Temperate bacteriophage differs from other bacteriophages

in

that temperate

bacteriophages

A reproduce at moderate temperatures

B inhibit synthesis of host-cell proteins

C can lysogenize the host cell

D

can

lyse the host cell

10

In Escherichia coli

the

synthesis of tryptophan is contro

ll

ed

by

the tryptop

ha

n

operon that

is

repressed in the presence of excessive tryptophan. When a mutant

strain that has lost the regulatory gene of the tryptophan operon is placed in s

medium that contains a

ll nu

trients the cells need to grow except tryptophan which

of the following will occur?

A The cells will grow until excessive tryptophan arrests the expression of the

operon .

B The cells will continue

to

grow even though excess tryptophan is synthesized.

C The cells will never grow unless tryptophan

is

added to the medium.

D The cells wi

ll

not grow until enough tryptophan has been synthesized

to

activate the corepressor.

11 Which of the following sequences of events occurs when E coli are released from

catabolite repression by transfer to low-glucose medium?

A cAMP levels fall cAMP is removed from CAP CAP complex binds to a site

on

DNA and activates transcription.

B cAMP levels rise cAMP binds to CAP cAMP-CAP complex binds to a site on

DNA and activates transcription.

C cAMP levels rise cAMP binds to CAP cAMP-CAP complex

is

removed from a

site on DNA and activates transcription.

D cAMP levels rise cAMP binds to CAP cAMP-CAP complex binds to a site on

DNA

and

represses transcription.


4/46

12 Which

of

the following statements about the control elements in the eukaryotic

genome are CORRECT?

(i) Attachment

of

RNA polymerase to TATAAT sequence at the -10 position

help in the formation of transcription initiation complex.

(ii) All upst ream regulatory elements increas e the basal activit')

of

promoter.

(iii) A gene

may

have multiple enhancers, each active at a different time or in

different cell type or locations

n

the organism.

(iv)

(v)

A

B

c

D

Binding of repressors to silencer can prevent a high r t ~

of

transcription.

Repressors bind

to

operator and effectively block the formation of

transcription Initiation complex.

(i) and (ii)

(ii) and (iii)

(iii) and (iv)

(iv) and (v)

13 The processing

of

pre-mRNA involves the following steps to produce functional

mRNA.

_

addition of GTP at the 3' cap

2 gene amplification

4

polyadenylation

splicing

A 1 and 2

B 2 and 3

C 3 and 4

D 1 and 4

4

Which of the following describes proto-oncogenes?

A They repair mistakes

n

DNA.

B They cause programmed cell death.

C The most commonly mutated proto-oncogene gene is the p53 gene.

D They are genes that codes for signal transduction molecules that are

associated with the cell membrane and regulate cell growth and division .

15 In Drosophilia the male is the heterogametic sex . The allele for white eyes is

recessive and sex-linked.

A female which is heterozygous at this gene locus was mated with a normal male.

White eyes will be present n

A all the offspring

B all the male offspring but none

of

the female offspring

C none of the female offspring and 50% of the male offspring

D none of the male offspring and 50% of the female offspring

16 A linkage group s composed of genes

which

A segregate at mitosis

B associate durig prophase I

C affect the same characteristic

D are situated on the same chrom osome


5/46

17 In mice, the gene for dappled coat (D) and its recessive alle le for plain coa t (d),

are located on the X chromosome. The gene for straight whiskers

(W)

and it

:

recessive allele for bent whiskers (w) , are autosomal.

A male mouse with plain coat and bent whiskers was mated on several occa sions to

the same female and the large number of offspring consisted of males and

fe

males

in equal numbers in all possible combinations of phenotypes ,

What is the genotype of the female parent?

A X

0

X0Ww

18

Six tubes containing preparations from animal t issue were set up as shown in the

table.

tube

contents

1

glucose + homogenized cells

2

glucose + mitochondria

3

glucose+ cytoplasm lacking organelles

4

pyruvic acid + homogenized cells

5

pyruvic acid + mitochondria

6

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

3, 4 and 6

D

3, 5 and 6

19 Treatment of intact mitochondria with an uncoupler, such as 2, 4-dinitrophenol in the

presence of ADP, P1 succinate and oxygen would have which of the following

effects on the rates of electron transport and ATP synthesis?

+

=

stimulation; o

=

o effect; -

=

nhibition)

rate of Electron

Transport

rate of ATP

synthesis

A + +

8

-

-

c

+

-

D

+

0

20 Su_bstrate-level phosphoryl

at

ion in the citric acid (Krebs) cycle depends directly

on

~ ~ ~ l

. \

A th ioester bond of succinyl GoA.

8 oxidative decarboxylation of isocitrate to a.-ketoglutarate

C FAD-dependent oxidation of succinate to fumarate

D phosphoanhydrate bond of 1 3-bisphosphoglycerate

2 Which combination correctly describes the light-dependent reactions of

photosynthesis?

site

of

e ~ t i o n in

chloroplast

ATP

NADP

A

granum

ATP __, ADP + P1

reduced

B

granum ADP

+P

1

_,

ATP reduced

c stroma ATP- ADP + P1

oxidised

D

I

stroma

ADP

+P1 _,

ATP

oxidised

10


6/46

22 Which statement ONLY applies

to

,carbon fixation

in

photosynthesis?

A GP (PGA) is reduced

to

carbohydrate.

B The reactions

are

not dependent

on

temperature.

C At low light intensity, these reactions limit the rate of photosynthesis.

I

D A 2-carbon compound

is

the acceptor for carbon dioxide.

23 Which of the following identifies features of oxidative phosphorylation OP) and

photophosphorylation (PP)?

ATP produce d electron low

oxygen as final can

be

cyclic

electron acceptor

A

OP

and PP OP and PP

OP only PP only

B

OP and PP

OP only

OP

and PP OP only

c

OP

only

PP

only

OP

only

OP and

PP

D

PP only OP and PP

PP

only

PP only

24 There are various forms of insulin medication available

on

the market. The table

shows information on three types of insulin medication.

types o Insulin onset o action peak action

duration

medication

X

15 min

30 to 90

min

3

to

5 hours

y

30 min 2 to 4 hours 6 to 8 hours

z

4 to 8 hours 12 to 18 hours

24 to

28 hours

Which of the following statement

is

CORRECT?

A Type X is good because a high blood glucose level can be reduced quickly.

B Type Y is better because it has a longer duration than type Z

and

hence

requires less injection.

C Type Z is t

he

best because it has the longest duration.

D Type Z can only be taken after a heavy meal.

25

Which function

is

carried out

by the

hormone insulin?

A Insulin breaks down glucose.

B Insulin catalysed the condensation of glucose to glycogen.

C Insulin facilitates the entry

o

glucose into cells.

D Insulin prevents glucose from being excreted by the kidney.

26

A person

has

poorly functioning p-cells

In the

islet of Langerhans. What

will be

the

concentration of glucose, insulin

and

glucagon in the blood after that person has

eaten a meal rich

in

carbohydrates?

glucose insulin glucagon

A high

low

high

B

high low

low

c low high

low

D low

high high

27 Which of the following

is

a difference between a motor neurone and a sensory

neuron?

A A motor neurone has a myelin sheath .

B A motor neurone has a cell body.

C A motor neurone synapse with

an

effector.

D A motor neurone responds to cholinesterase .

12


7/46

28 When a stimul

us

arrives at a nerve ending, the membrane becomes depo

ia

rised.

The events during depolarisation are listed

be

low.

2

3

4

K channels open,Na channels close.

Na channels open and Na floods in.

Potential difference inside the membrane

outside.

Potential difference inside the membrane

outs ide.

Which is the CORRECT order of events?

A 1,

2, 3,

4

B

1,

3,

2, 4

c 4,

1,

2, 3

D

4,

2, 3,

1

is 40 mV compared

is -65 m

compared

29

A drug might act

as

a stimulant of the nervous system

if

t -

A makes the membrane permanently impermeable to sodium

to the

to the

B increases the release of substances that cause the hyperpolarisati

on

of the

neurons

C increases the sensitivity of the pre-synaptic membrane to acetylcholine

D increases the sensitivity of the post-synaptic membrane

to

acetylcholine

30 The post-synaptic membrane of a nerve may be stimulated by certain

neurotransmitters

to

permit the influx

of

negative chloride ions into the cell. Th

is

process will result n

A an action potential

B membrane depolarization

C the production of

an

IPSP

D the production of an EPSP

3

31

Certain drugs act at synapses and affect the action of neurotransmitter substances.

The table shows

the

effects of four different drugs.

drug

effect

1 inhibits the enzyme cholinesterase

2

prevents the release of acetylcholine

3

competes with acetylcholine at receptor sites

4

inhibits the enzyme which destroys noradrenaline

Which two drugs would prevent synaptic transmission to a skeletal muscle?

A 1 and 2

B 1 and 4

C 2 and 3

D 2 and 4

32 Many signal transduction pathways use second messengers to

A amplify the message by phosphorylating proteins

B relay a signal from the outside

to

the inside of the cell

C relay a signal from the inside of the membrane throughout the cytoplasm

D transport a signal through the plasma membrane

33 From an evolutionary point of view, plant tendrils derived from leaves and those

derived from stems are examples of

A analogous structures resulting from convergence only

B homologous structures resulting from convergence only

C n l o g o ~ s structures resulting from divergence only

D homologous structures resulting from divergence only

14


8/46

34 Charles Darwin discussed

all

ofthe' followi

ng

EXCEPT

Organisms tend to produce more offspring than can survive in each

generation.

Individuals

in

a population compete with one another for limited resources.

C Gene mutations are the source of variation for evolution.

D Individuals within species exhibit variability

in

form and function.

35 RFLP analysis is a technique that

A

is used

to

determine whether a gene

is

transcribed

in

specific cells

B measures the trans fer frequency of genes during conjugation

C

is

used to detect genetic variation

at the

protein level

D uses hybridization to detect specific DNA restriction fragments in genomic DNA

36 A microarray is a large collection of specific DNA oligonucleotides spotted in a

defined pattern

on a microscope slide. What is the most useful experiment that can

be

done with such a tool?

A Predicting the presence of specific metabolites in a cell.

B Comparing newly synthesized nuclear RNA with cytoplasmic

RNA

to locate

introns.

C Comparing RNA produced under two different physiological conditions

to

understand patterns of gene expression .

D Comparing proteins produced under

two

different physiological conditions to

understand their function .

15

37 Restriction mapping of small DNA molecules is an important technique of modern

biology .

An

example of the mapping of a circular plasmid (pBR322) DNA is

described in this test. Purified samples of plasmid DNA were digested with the

restriction enzymes Ace , Ava , BamHI, EeoRI or Pvu l, or with various combinations

of these enzymes,

and the

reaction mixtures were fractionated

by

agarose gel

electrophoresis. Bands of

DNA

fragments were visualized

by

staining with ethidium

bromide.

The image

of the gel is displ

ayed

in Fig. 37 .1,

and

the cleavage sites on the circular

DNA are shown in Fig . 37.2. Using the information in Fig . 37 .1, determine the

cleavage sites of the enzymes.

(An EeoRI

site is already shown in Fig.

37

.2) .

o

Ava BantHT Ace/ Ar cl Ace f EcoRI

C

SeL:tion B:

Consists

of

f

Essay

Questions

Answer any

one

question.

W ri

ie

your answers on the separate writing papers provided.

At the end

of the

examination, fasten all your work securely

together The number

of

marks is given in brackets [ ] at the

end

of each question or part question.

Do

not

open

this booklet

until you

are

told

to do

so

Section A

Section B

Total

1

2

4

5

6

7

8

9

1/2

/10

/10

/10

/5

/10

/10

/10

10

/5

/20

This question paper consists

of

24 printed pages and blank page. (including this cover page)

[Turn

over


12/46

Question 1

Section A Structured Questions 80 marks)

Answer all questions

in

this section.

In the search for new biofuels , research has been done into the digestion

o

wood

waste by fungi. The cellulase enzymes produced by the fungi break cellulose into

sugars. These sugars can then be converted into ethanol, a biofuel.

Fig. 1 1 shows the stages

in

this digestion process.

~

/

OH

cellulose / A /

OH

OH

p

disaccharide

Inzyme1

Inzyme 2

CH

20 H

H

o O

~

H OH

Fig 1 1

a)

i)

Name bonds A and 8 shown in Fig . 1.1. [2]

A

8

For

Examiners

use


13/46

i

i) State how bond B is broken

in

the digestion o the dfsaccharide. [1]

b) Explain why different enzymes are involved in each stage

o

the digestion

process. [2]

/

c) Fig . 12 shows diagrams

o

two different stages

o

meiosis in cells taken from

the testis

o

a grasshopper, Chorthippus brunneus The stages are labelled

and

Q

cell membrane

centriole

p

Name the two stages. [1]

p

Q

s

T

a

Fig 1 2

3


14/46

) Name the structures labelled on the two diagrams. [2]

R

s

T

e) State the ways in which meiosis can lead to genetic variation. [2]

.. ----

.

_______________ __ -- . .

Total: [1 ]

For

Examiners


15/46

Question

2

Fig. 2 shows the synthesis

of

macromolecule in eukaryotic cells.

& JfWM

DN

IV JI '>

RN

-

Promotor

Anfisenss{templafe)

/

, ..

Antisense fempJele)

, Fig 2

a)

a

me the process shown in Fig. 2 and explain your answer. [2]

bp

With

re

ference to Fig. 2, describe the characteristic

of

a template strand. [3]

-----

.

5

us


16/46

{c Name the macromolecule that

s

produced in this process. [1]

{d Describe in detail how this process is initiated. [4]

Total: [1 ]


17/46

Question 3

Lambda is a bacteriophage that uses E coli as its host cell.

Figu

re 3

1A is an electron micrograph

EM)

of a wild-type bacteriophage lambda .

Figure 3.1 B is an

EM

of

a laboratory-cultured lambda.

A

B

Fig.

3 1

a} 1 he actual diameter, Y is 50 nm.

Calculate the magnification of the bacteriophage lambda, shown in Figure 3.1A.

Show your working . [2]

Answer x .................. ...... ....... . ..

or

Examiners

use


18/46

b) State the main difference,

visible n Fig 3.1

between the wild-type and the

laboratory-cultured bacteriophage lambda. [1]

{c) Suggest how laboratory-cultured bacteriophage lambda binds to cells of its

host, E coli [1]

/

d} Expl ain why it is sometimes difficult to distinguish between a plasmid and the

DNA of bacteriophage lambda inside an E coli cell when viewed using an

electron microscope. [ ]

e) The lac operon is an inducible operon in E coli It is regulated differently at

di

ff

erent conditions determined by the availabilities of lactose and glucose.

Under

what

biological conditions is C P active, and how is this activity

regulated? [2]

----

- - - - -

-

8


19/46

f) or each of the following conditions, describe how regulation of lac operon

gene expression will be altered

i.e.

- how will it respond to the presence

or

absence of lactose).

i)

A mutation in the repressor

gene

such that the repressor does not bind

lactose. [1]

ii) A mutation in the repressor gene such that once lactose is bound to the

repressor, the lactose is never released. [1]

iii) A mutation in the operator region such that lac repressor no longer

recognizes the operator. [1]

Total: 10]

9

For


20/46

Question 4

Ce ntro mere is a specialized structure

on

the chromosome, appearing during cell

division as the constricted central region where the two chromatids are held together

and form an X shape.

a) Name structure A and B [1]

A

B

Fig 4

b) Describe the structure of centromere . [2]

c) Describe the roles of centromere. [ ]

-

Total: [ ]

1

Examiners

use

or


21/46

Question

5

William Bateson and Reginald Punnett

were

interested in trait inheritance in the

sweet pea plants. They were studying two

genes

- the gene for f lower colour P,

purple, and p, red) and the gene affecting the shape of pollen grains (L, long, and I,

round). They crossed the pure lines purple

flower

long pollen grain and red flower

round pollen grain and then self-crossed the F

progeny.

According to Mendelian genetics, the expected phenotypes of the F

2

generation

would occur in a 9:3:3:1 ratio. To their surprise, they observed an increased

fre

quency

of purple flower

long

pollen grain and red flower round pollen grain , and

a decreased frequency of purple flower round pollen grain arid red

f i C ~ e r

long

po llen grain.

purple flo

wer

long pollen grain 284 216

purple flower round pollen

21 72

grain

red flower long pollen grain 21 72

red flower round pollen grain 55

24

(a) Use

a l test to determine if the difference between the observed number and

the expected number is significant.

[5]

Degree

of

freedom

0.1

1 2.

71

2

-

4.

61

3 6.25

where = sum of ..

v = degrees of freedom

c = number of classes

0.05

3.84

5.99

7.82

Probability, p

0.02 0.01

5.41 6.64

7.82 9.

21

9.84 11.35

v = c 1

0 =observed value

E = expected value

0.001

10.83

13.82

16.27

Examiners

use .


22/46

Please write y ur answer in the space provided below

2


23/46

{b Coat colour in mouse is the result of melanin . Melanin is s y n t h e s i ~ e vi

several biochemical steps from the amino acid tyrosine. The control of coat

colour is complex and involves at least five major interacting genes.

One of these genes gene

C

controls the production of the pigment melanin

while another gene gene B is responsible for wh th r the colour is black B)

or brown

b) .

In albinism the homozygous recessive condition cc blocks the

expression of coat colour.

Two heterozygotes black mouse are crossed producing the first generation of

offspring. Construct a genetic diagram to illustrate the outcome of this cross . [5]

Total: [10]

3


24/46

Question

Fig. 6 shows an outline diagram

o

the Krebs cycle. A two carbon acetyl group

enters the cycle by combining with a molecule of oxaloacetate. A molecule o citrate

is formed which

is

decarboxylated and dehydrogenated to regenerate the

oxaloacetate.

i d a t i o n

fatty acids acetyl (2C)

c_oA--:::==---:::::-

N ~

reduced

NAD

Co

A

citrate (6C)

\p

intermediate (5C)

a

intermediate (4C) intermediate (4C)

{a) Explain the following terms:

i) decarboxylation [1]

dehydrogenation [1]

intermediate

4C)

Fig 6

4

or

Examiners

use


25/46

{ii Describe the steps where decarboxylation takes place you must state

the step as shown in Fig.

6

the substrate , the product and enzyme

of the steps). [2]

b)

F

ig

. 6 also shows that fatty acids c n

be

converted into acetyl CoA units by a

process known as 13-oxidation. Both this process and the Krebs cycle require

NAD. The Krebs cycle also requires FAD. The hydrogen atoms

r e l e ~ ~ e

in

3

oxidation and the breakdown of acetyl CoA in the Krebs cycle reduce the NAD

and FAD molecules.

State where the reduced NAD nd reduced FAD molecules are reoxidised and

describe what happens to the hydrogen atoms. [3]

5


26/46

c) The liver

is

responsible for producing enzymes which detoxify alcohol by

b

re

aking it down into smaller units. This breakdown by enzymes uses NAD.

This means that other reactions that use NAD are less likely to take place. The

build-up of fats in the liver is one

o

the first signs

o

liver damage due to

excessive alcohol intake.

Using the information

in

Fig. 6 explain why the build-up o fats occurs in the

liver of

an

individual who consumes large amounts o alcohol. [3]

Total: [1 ]

6

or


27/46

Question 7

Fig. 7 shows the light dependent stage of photosynthesis.

NADP

P .

H H H

H .

.H

B

I ,.

H H

. _

_ _ _ _

_ ___ __ _

_:_ '-'_:_...;..____I_

a}

Name region A and B [1]

A

B

/

Fig. 7

b)

scribe what happens when a photon of light falls on photosystem II. [2]

17

Examiners

use -


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c) Name the tw products from this process and describe their functions in

Calvin Cycle. [4]

{d With reference

to

Fig.

7

explain how a high concentration

H

ion is generated

on that side of the membrane. [2]

e) State one difference between non-cyclic photophosphorylation and cyclic

photophosphorylation. [1]

Total: [1 ]

8


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Fig. 8.2 shows the realationship between membrane potential and the

m

mbrane permeability of sodium ion Na+) and potassium ion K+).

Fig

8 2

c) With reference to Fig. 8.2, describe

how

the membrane permeability of sodium

ion Na+) and potassium ion K+) affects the membrane potential. [3]

20


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d) Explain how the membrane permeability of sodium ion

Na+)

and potassium

ion K+) results in the returning o resting potential from hyperpolarisation. [2]

.................

..

. ..................

Total: [1 ]

2


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uestion9

isle Royale is a small island in the middle of Lake Superior located between the

USA and Canada. The most abundant large herbivore on the island

is

the moose.

The most abundant large predator is the

wolf

. Studies have shown that moose

make up over 90 of the wolf diet.

Fig. 9 shows the changes

in

the moose and wolf populations between 1955 and

2005.

number

of

moose

25

2

.

'

15

1

;

5

0

1955

965

Key:

moose

- -wo l f

. .

1975

1985

1995

year

Fig

9 1

5

4

3

2

1

0

2 5

number

of

wolves

or

Examiner s

use


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a) Describe

nd

explain the changes in the two populations between 1970 and

985. [3

b) During the past two decades, biologists have been concerned

th t

the wolf

population of Isle Royale might become extinct. Numbers have reached as low

as ten in some years. With the population at such low levels, genetic

weaknesses can result from inbreeding. Inbreeding is the result of mating

between closely related individuals.

Explain why inbreeding can lead to genetic weakness

in

the population. [2]

Total:

[5]

23


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Section

8:

Essay Questions 20

marks)

Answer only one question.

Write your answers on the writing

paper

provided.

You r answers should be illustrated by large, clearly labelled diagrams, where appropriate.

Your answers must be in continuous prose, where appropriate.

Your answers must be set out

in

sections a), b) etc., as indicated

in

the question.

Question

1

a) Compare the structure and organisation of prokaryotic and eukaryotic genomes. [8]

b) State the various ways in which prokaryotic and eukaryotic transcription differs . [8]

c) State the various ways

in

which eukaryotic gene expression may be controlled at [4]

tr

anslational and posttranslational level.

Question 2

a) Describe the replication cycle of retrovirus, HIV. [5]

b) Explain the link between the infection ofT lymphocytes by HIV and the onset of [3]

the symptoms

of

AIDS.

c) The drug zidovudine AZT) is n inhibitor of the enzyme reverse transcriptase. [2]

Explain

why

AZT slows down the progess of HIV infection.

{d

A man with ~ y p e 1 diabetes was held hostage. He was deprived of his daily [10]

injection and died. What does this injection contain and

how

could it have saved

his life?

[Total: 20]

END OF

PAPER

24


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Name

BIOLOGY

ICivics I

Group

DUNMAN HIGH SCHOOL

SENIOR HIGH

2010 PRELIMINARY EXAMINATIONS

General Certificate of Education

Advanced

Level

YEAR

SIX H2 BIOLOGY (9648)

9648/03

PAPER

3

22 September 10 Wednesday

hour

READ

THESE

INSTRUCTIONS FIRST.

Do not open this booklet until you are told to do so.

Write yo

ur

name, index number and civics group at

the

top of this page.

Answer

all

questions.

This

paper

consists of:

4 Structured Questions

Write yo

ur

answers

in

the space provided on the question

pa

er

ss a:y

Ques t ion

Write

your

answers on the separate writing papers provided.

1 SPA Planning Task

Write your answers on the separate writing papers provided.

Do not open t

his

booklet until you are told to

do

so

FOR EXAMINER S USE

1

/10

2 /10

3 /10

4

/10

5

/20

SPA

/12

planning

TOTAL

This question paper consists of 12 printed pages and blank page. (including this cover page)


36/46

Question 1

Stn.ictured Questions (40 marks

Answer all questions in this section.

Insulin and human growth hormone (HGH) are proteins of medical importance.

They can

be

produced on a large scale using

Escherichia coli.

(a)

) Explain the reasons for using microorganisms such as E coli, in the

large scale production of insulin and HGH. [3]

)

Table

1 1

summarizes the sequence

of

events in the production

of HGH

by E coli.

Complete Table

1 1

by adding one relevant statement in each of the

empty boxes. [3]

Table 1 1

2

or

Examiner s

use


37/46

{b List all components

to

be added

n

the PCR tube in order to perform a

successful PCR reaction?[2]

c) List and explain

one

major advantage and

on

major disadvantage of PCR.

[]

Total: [1 ]

3


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Que

stion

2

Genetic screening of Huntingdon s disease (HD) can be carried out, using a

process similar to genetic fingerprinting, to find the length

of

repe ted triplet or

stutter ,

in an

allele.

After treatment with a restriction enzyme, the digested fragments are separated by

gel electrophoresis.

{a) Explain why fragments of DNA from restriction digestion can be separated by

gel electrophoresis. [3]

(b) Fig. 2 1 shows a family s history of Huntingdon s disease (HD).

genera

tion

1

gen eration

A

generation

3

B

generation 4

c

key : male HD D male without HD female with HD 0 female without HD

Fig. 2 1

DN

A from individuals A B and C from the family shown in Fig. 2 1 was

an

alysed. The resulting banding patterns are shown in Fig. 2.2.

4

or

Examiners

use


39/46

range

of

lengths {

of abnormal

allele

range of l

eng

ths {

of norm al allele .

A

B

Fig 2 2

c

direction

of

movemen t of

DNA

fragments

Explain

why

the

DN

of

the following bands in Fig . 2.2 are not -

l le

same

length :

i the three normal alleles; [1]

-

-

-1

1

ii)

the three abnormal alleles. [1]

- -

1

_ _ _ _____

__________

____

{c) Describe RFLPs. State one use of RFLPs. [3]

- - 1

---

1

5


40/46

d) What is eDNA? How is it generated? [2]

Total: [1 ]

6


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Qu

estio

n

3

Severe combined immunodeficiency SCID) is a primary immune deficiency. It

usually results in the onset of one or more serious infections within the first few

months of life. These infections are serious, and may even be life-threatening.

Fig. 3 shows the inheritance of SCID

in

a family.

2

3 4 5

6 7

8

Affected female

9

10

12

Normal female

Q

Affected male

Normal male

D

Fig 3

(.a

xplain the mode of inheritance illustrated in Fig.3. [2]

---

7

or

Examiners

use


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b) What is the underlying mechanism that leads to SCID as shown in Fig. 3? [4]

..

c) Explain why bone marrow transplant is the most effective form of treatment for

SCID. [2]

d) What are the advantages o using gene therapy compared to bone marrow

transp

la

nt?

2]

..

..

Total: [10

8


43/46

Question 4

Fig

4

shows the ethene production

of

a normal tomato and a Fiavr Savr

genetically modified tomato left on a plant for three weeks prior to picking. Naturally

produ

ce

d ethene

in

fruits speeds up the ripening process.

ethene

conce

ntration

4

8 12 16

time /da

ys

Fig 4

- ormal

20

genetically

modified

24

(a) Com pare the production

of

ethene

in

normal tomatoes with that in genetically

modifi

ed tomatoes. [3

--------

----- -

;

(b) Suggest what effects this genetic modification would have on the tomatoes. [2]

9

For

Examiner s

use


44/46

Not only are plants genetically engineered GE) to affect their ripening, some plants

are also genetically engineered to become herbicide-resistant. Farmers who grow

GE herbicide-resistant crops are advised not to rely exclusively on glyphosate and

need to incorporate a range of weed management practices, including using other

herbicide mixes.

c) Explain why the farmers are advised to incorporate a range

of

weed

management practices.

[ ]

Farmers who grow GE crop are advised not to grow non

GE

cr:op near these GE

crop, especially varieties from the same family as the

GE

crop

that hey

are

growing.

d) Explain why they are advised against this? [3]

__ 1

Total:

[

]

10


45/46

Essay Questions 20 marks)

Answer the following question.

Write your answers on the writing paper provided.

Your answers should be illustrated by large, clearly labelled diagrams, where appropriate.

Your answers must be in continuous prose, wh r appropriate.

Your answers must be set out in sections a),

b)

etc., as indicated in the question.

Question

a) Discuss the ethical and social implications of genetically modified crop plants [ 0]

and animals.

b)

Discuss th advantages and disadvantages of micropropagation compared with

[

0]

traditional propagation methods

[Total: 20]


46/46

SPA Planning Task

T

he

task

is

about the effects of limiting factors

on the

rate of photosynthesis in

sun

and

shade

leav

es.

Leaves that make efficient use

of

relatively dim light are called shade leaves. They do not

photosynthesize efficiently at relatively high light intensities. Leaves that make efficient use of

relatively high light intensities are called sun leaves. They do not photosynthesize efficiently in

dim light.

Y

ou are required

to plan an investigation to compare

the

effect of

changing one limiting

factor on

the

rate of

photosynthesis in sun and shade leaves.

F

or

your Plan, choose one species of plant that exhibits both sun and shade leaves.

Do

not

use

vari

egated leaves. Choose one of the following limiting factors:

light intensity

temperature

carbon dioxide concentration

Leaf discs can be used

to

determine the effect

of

a variable on the rate of photosynthesis.

The discs can be cut out using a cork borer or a large plastic drinking straw. The discs are then

placed n a syringe with the syringe slowly filled up with water or very dilute sodium hydrogen

carbonate NaHC0

3

solution. Air inside the syringe is expelled by pushing n the plunger. Air is

then drawn out in the intercellular air space

sof

the

leaf

discs by applying your finger firmly to the

nozzle and attempting to withdraw the plunger. As the air is drawn out, the leaf discs sink and are

then ready to use.

Submerged

leaves

must

be used in your Plan.

Your planning must be based

on

the assumptions that you have access to:

sun and shade leaves of your chosen plant

the apparatus and materials to produce submerged leaf discs

> school

or

college laboratory resources

Give full details

n

your Plan to include:

the apparatus and materials to be used

a detailed method to include procedures you would adopt to ensure the results obtained

would be as precise and reliable as possible

a risk assessment and safety precautions

Indicate briefly how you would present and analyse your data to draw your conclusions. [12]

2010 a Level h2 Biology Dunman High

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