2001

This question paper consists of 11 printed pages and 1 blank page.

SB (SLC/KN) S11940/1© CIE 2001 [Turn over

CAMBRIDGE INTERNATIONAL EXAMINATIONS

General Certificate of Education Advanced Subsidiary Level

BIOLOGY 8700/2PAPER 2

OCTOBER/NOVEMBER SESSION 2001 1 hour

Candidates answer on the question paper.No additional materials are required.

TIME 1 hour

INSTRUCTIONS TO CANDIDATES

Write your name, Centre number and candidate number in the spaces at the top of this page.

Answer all questions.

Write your answers in the spaces on the question paper.

All working for numerical answers must be shown.

INFORMATION FOR CANDIDATES

The intended number of marks is given in brackets [ ] at the end of each question or part question.

CandidateCentre Number Number

Candidate Name

FOR EXAMINER’S USE

3

2

1

4

TOTAL

6

5

http://www.xtremepapers.net

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1 Fig. 1.1 shows a three-dimensional diagram of part of a plant stem.

Fig. 1.1

(a) Identify the structure labelled A and state one function it performs in the stem.

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

......................................................................................................................................[1]

AB

C

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8700/2/O/N/01 [Turn over

(b) State three main structural features that help A to carry out this function.

1. ......................................................................................................................................

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

2. ......................................................................................................................................

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3. ......................................................................................................................................

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(c) The cell labelled B is involved in the transport of the products of photosynthesis up anddown the stem.

Identify the cell labelled C and explain how it is involved in this process.

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......................................................................................................................................[3]

[Total : 7]

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2 Fig. 2.1 shows diagrams of two alveoli from the lungs of a smoker, A, and a non-smoker, B,after exhalation is complete.

Fig. 2.1

(a) Identify the fibres labelled X, in Fig. 2.1, that surround the alveoli.

......................................................................................................................................[1]

(b) With reference to Fig. 2.1, explain why people who have smoked heavily for a long timeoften have difficulty in breathing and in obtaining sufficient oxygen.

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......................................................................................................................................[3]

X

A B

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(c) State two pieces of epidemiological evidence and one piece of experimental evidenceto link smoking with lung cancer.

epidemiological evidence

1. ......................................................................................................................................

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

2. ......................................................................................................................................

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

experimental evidence

1. ......................................................................................................................................

......................................................................................................................................[3]

[Total : 7]

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3 Fig. 3.1 is a diagram of part of an α helix of a polypeptide chain commonly found in manytypes of protein.

Fig. 3.1

(a) (i) Name the repeating monomer of a polypeptide chain.

...............................................................................................................................[1]

(ii) Explain what would happen to the α helix if the polypeptide chain was heated to atemperature above 60 °C.

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

...............................................................................................................................[2]

C

C

C

C

C

C

C

CC

C

C

CC

C

C

C

C

C

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7


(b) In globular proteins, the polypeptide chain bends and folds to give a more compactshape. This is the tertiary structure of the protein.

Name three types of bond that help to maintain the tertiary structure.

1. ......................................................................................................................................

2. ......................................................................................................................................

3. ..................................................................................................................................[3]

(c) Monosaccharides can also be linked together to form long chain molecules calledpolysaccharides.

State two ways, other than the names of the monomers present, in which the structureof a polysaccharide chain differs from that of a polypeptide chain.

1. ......................................................................................................................................

2. ..................................................................................................................................[2]

(d) The fibrous protein collagen and the polysaccharide cellulose both possessconsiderable tensile strength.

List two features that contribute to the strength of

(i) collagen;

1. ...............................................................................................................................

2. ...........................................................................................................................[2]

(ii) cellulose.

1. ...............................................................................................................................

2. ...........................................................................................................................[2]

[Total : 12]

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4 Fig. 4.1 shows the process of translation occurring at a ribosome in a cell that synthesisesenzymes that are secreted into the gut.

Fig. 4.1

CC C

A A AUU U U

U U}}R

P

A G A

S

direction of movement ofribosome along mRNA

growing proteinmolecule

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9


Table 4.1 shows some triplet base sequences of mRNA and the amino acids for which theycode.

Table 4.1

(a) With reference to Fig. 4.1 and Table 4.1,

(i) name the amino acid P;

...............................................................................................................................[1]

(ii) state the base sequence at S;

...............................................................................................................................[1]

(iii) state the name given to the triplet base sequences on mRNA;

...............................................................................................................................[1]

(iv) describe the change that would occur to the protein if the base sequence at R wasUUU instead of AUU.

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

...............................................................................................................................[1]

(b) Describe what happens to the enzyme molecule after it has left the ribosome until itleaves the cell.

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

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......................................................................................................................................[4]

[Total : 8]

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mRNA amino acid

AUU isoleucine

AUC isoleucine

AUG methionine

UUU phenylalanine

UCU serine

CAU histidine

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5 Phagocytes are involved in removing bacteria from infected tissues.

Fig. 5.1 is a drawing made from an electron micrograph of a phagocyte that has engulfedsome bacteria.

Fig. 5.1

(a) Name A to D.

A .......................................................................................................................................

B .......................................................................................................................................

C .......................................................................................................................................

D ...................................................................................................................................[2]

(b) Explain why it would not be possible to see the same detail of a phagocyte, as shown inFig. 5.1, using a light microscope.

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

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

......................................................................................................................................[3]

(c) Explain how phagocytes engulf and destroy invading organisms, such as bacteria.

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......................................................................................................................................[4]

[Total : 9]

A B C

D

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6 (a) Complete Table 6.1 to show which of the four statements about the transmission andcontrol of disease apply to cholera, malaria, HIV/AIDS and tuberculosis (TB). In eachbox, use a tick (✓) to show that the statement applies and a cross (✘) if it does not.

Table 6.1

[4]

(b) Sickle cell anaemia is an inherited disease that is common in areas of the world wheremalaria is endemic.

Explain why sickle cell anaemia is common in areas where malaria is endemic.

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

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

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......................................................................................................................................[3]

[Total : 7]

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statement cholera malaria HIV/AIDS TB

causative organism is a bacterium

causative organism is water-borne

transmitted by an insect vector

sexually transmitted

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8700/2/O/N/01

BLANK PAGE

NOVEMBER 2001

GCE ADVANCED SUBSIDIARY LEVEL

MARK SCHEME

MAXIMUM MARK : 50

SYLLABUS/COMPONENT : 8700/2

BIOLOGY(STRUCTURED QUESTIONS)


of 3 Mark Scheme Syllabus Paper

AS Level Examinations – November 2001 8700 2

1 (a) xylem vessel, transport of, water / ions; 1

(b) no cross walls;wide lumen / AW;strengthened / lignified / thick cell wall;no, cytoplasm / cell contents / organelles / hollow / empty;pits; 3 max

(c) companion cell;

movement of sucrose / other named substance;into / out of, sieve tubes / loading / unloading;through plasmodesmata;provides energy;active transport; 3 max

[Total: 7]

2 (a) elastin / elastic fibres; 1

(b) no recoil / alveoli do not recoil; (A) contractair not forced out;air not refreshed in alveoli;concentration of oxygen, falls / not maintained;less oxygen diffuses into the blood; 3 max

(c) epidemiological evidence

increase in cigarette smoking, increase in cases / deaths from lung cancer ~ 20 years later;more men than women smoked in the past, linked to greater number of cases / deaths among men; (A) anything similar to thislung cancer rare / unknown, before cigarette smoking became common;most people with lung cancer, smoke / have smoked;lung cancer very rare in non-smokers;lower incidence in smokers who do not inhale; (e.g. pipe and cigar smokers)ref to national differences in smoking and cancer / ref to developing countries;ref to studies involving British doctors;ref to evidence from passive smoking;AVP; 2 max

experimental evidence

experimental animals develop tumours similar to human lung tumours;carcinogens have been isolated from tar;when painted on animal skin induce tumours; 1 max

[Total: 7]



3 (a) (i) amino acid; 1

(ii) lose its shape / disrupted / uncoils / becomes straight chain;denature;hydrogen bonds break; 2 max

(b) disulphide / sulphur bridges;van der Waals / A/W;hydrogen ;ionic; 3 max

(c) may be branched;glycosidic links;no R groups;repeating unit structure / one monomer;AVP; 2 max

(d) (i) three polypeptides twisted around each other;hydrogen bonds between polypeptides;covalent links between chains;every third amino acid glycine, small so tight coil;lay parallel to form fibrils;ends staggered / fibrils overlap, so strong; 2 max

(ii) many –OH groups;hydrogen bonds within the molecule;hydrogen bonds between molecules;straight chain (not helix) / unbranched / linear;60-70 chains / associated to form microfibrils;arranged in bundles to form, macrofibrils / fibres; 2 max

[Total: 12]

4 (a) (i) serine; 1

(ii) UAG; 1

(iii) codon; 1

(iv) phenylalanine, not isoleucine as next amino acid; 1

(b) secondary structure / alpha helix / pleated sheet;further folding / tertiary structure;ref named bond(s);transported in ER;Golgi;packaged / sugars added / trimmed;vesicles;exocytosis; 4 max

[Total: 8]



5 (a) A nucleus;B mitochondrion;C phagosome / vacuole;D lysosome;

half mark each 2

(b) lower resolution in light microscope;ref wavelength of light;maximum is half wavelength;200 nm;many organelles / named example, smaller than this; 3 max

(c) attachment to cell membrane;receptors;role of antibodies / opsonins;folding inwards of cell membrane / endocytosis;formation of vacuole / phagosome;lysosomes fuse with vacuole;toxins kill bacteria;enzymes digest bacteria; 4 max

[Total: 9]

6 (a)

one mark per row4

(b) people who are heterozygous / carriers;resistant to malaria;children of heterozygotes;1 in 4 chance of inheriting sickle cell anaemia;further detail of inheritance (e.g. Punnet square);only attacks Hb

AHb

A / healthy R.B.Cs; 3 max

[Total: 7]

Total mark for paper = 50

statement cholera malaria HIV/AIDS TB

causativeorganism is abacterium

� � � �

causativeorganism iswater-borne

� � � �

transmittedby an insectvector

� � � �

sexuallytransmitted

� � � �

This question paper consists of 4 printed pages, 3 blank pages and a Report Form.

SB (SC) S09595/1© CIE 2001 [Turn over

CAMBRIDGE INTERNATIONAL EXAMINATIONS

General Certificate of Education Advanced Subsidiary Level

BIOLOGY 8700/3PAPER 3 Practical Test

OCTOBER/NOVEMBER SESSION 2001 1 hour 15 minutes

Candidates answer on the question paper.Additional materials:

As listed in Instructions to Supervisors

TIME 1 hour 15 minutes

INSTRUCTIONS TO CANDIDATES

Write your name, Centre number and candidate number in the spaces at the top of this page.

Answer both questions.

Write your answers in the spaces provided on the question paper.

INFORMATION FOR CANDIDATES

The intended number of marks is given in brackets [ ] at the end of each question or part question.

You are advised to spend 55 minutes on Question 1 and 20 minutes on Question 2.

CandidateCentre Number Number

Candidate Name

FOR EXAMINER’S USE

TOTAL

2

1


2

8700/3/O/N/01

Question 1 [55 minutes]

You are required to investigate the effect of temperature on the enzyme urease. Urease catalysesthe following reaction.

urea + water → ammonium carbonate

Proceed as follows:

Prepare two tins or beakers to act as water-baths. The temperature of the water in one should beabout 50 °C, in the other, the water should boil. Label three test-tubes A, B and C respectively.Add one tablet of urease to tube A and place the bottom of the tube on the bench on a pad ofpaper or cloth.

Using a glass rod, very gently crush the tablet into a powder, taking care not to break the bottomof the test-tube. Repeat this procedure for tubes B and C. To each of the three tubes, add 3 cm3

of distilled water and stir to dissolve. Place tube A in the water-bath at 50 °C, tube B in the boilingwater and tube C in a test-tube rack at room temperature.

After five minutes, remove tubes A and B from the water-baths and cool them under a runningtap. Measure out 10 cm3 of urea solution into each of three further test-tubes.

Adjust the temperature of one water-bath to 38–40 °C, the other is no longer needed. Place tubesA, B and C and the three containing urea solution into this water-bath. After three minutes, tipthe contents of one of the urea tubes into each of tubes A, B and C. Stir the contents using aglass rod. Note the time and leave these tubes in the water-bath for 30 minutes.

Set up a burette containing 0.05 mol dm–3 sulphuric acid.Label three flasks or beakers A, B and C respectively.

You should begin Question 2 during the 30 minute period.

After 30 minutes, remove tubes A, B and C from the water-bath. Pour the contents of thesetubes into the flasks or beakers similarly labelled. To each flask, add four drops of indicator.

(a) Record the colour of the contents of the three flasks.

A………………………… B ………………………… C ………………………… [1]

Titrate the contents of A, B and C in turn with sulphuric acid. Add the sulphuric acid drop by drop,shaking gently after each drop, until an end point is reached (a grey/pink colour).

(b) Record your results in a suitable table.

[5]

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Use(c) Explain your results as fully as possible, using your biological knowledge.

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(d) State the ways in which you would have expected the results to be different if tubes Aand B had been maintained at their respective temperatures for one hour instead of fiveminutes.

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

......................................................................................................................................[2]

(e) State two variables that are not controlled in your procedure that are likely to affect therate of enzyme reaction.

.............................................................. and ...............................................................[2]

(f) Other than controlling the variables you mentioned in (e), but using the same apparatusand materials, state three ways in which you could obtain more reliable results if moretime was available.

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[Total : 18]

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8700/3/O/N/01

Question 2 [20 minutes]

Slide K1 is a stained transverse section of the stem of a herbaceous flowering plant.Examine K1, using your microscope.

Fig. 2.1 shows an outline of half of the section, without any of the details.

Fig. 2.1

(a) Draw the outlines of all the vascular bundles in the half section on Fig. 2.1. Your planshould show accurately the numbers of the bundles, their sizes and positions. [5]

Slide K2 is a stained longitudinal section of the stem of the same species of plant as K1.Examine K2, using your microscope.

(b) (i) On Fig. 2.1, indicate one possible position at which K2 could have been taken.Label this ‘position of K2 ’. [1]

(ii) Give reasons for your decision in (i) based on your observations of both slides.

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

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

...............................................................................................................................[1]

[Total : 7]

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REPORT FORM

The teacher responsible for this subject is asked to answer the following questions:

(a) Was the candidate physically handicapped in drawing or using a microscope? If so, give briefdetails.

(b) Was the candidate handicapped by deficient material or apparatus? If so, give brief details.

(c) Was it necessary to make any substitutions for the materials sent from Cambridge? If so, givebrief details of the circumstances.

(d) Any comments.

Signed ………………………………

N.B. Information that applies to all candidates need only be given on the first candidate’s answer book.

NOVEMBER 2001

GCE ADVANCED SUBSIDIARY LEVEL

MARK SCHEME

MAXIMUM MARK : 25

SYLLABUS/COMPONENT : 8700/3

BIOLOGY(PRACTICAL)




1 (a) three similar colours – green – a variation of; 1

(b) table headings: flask / beaker (contents of);volume of sulphuric acid added in cm

3 ;

three burette readings;tube B a value below 3 cm

3;

value A less than that of C;two columns ( two rows ) only and need not be lined;value of C greatest; 5 max

(c) ref to molecular effect, enzyme colliding with substrate togive ammonium carbonate;titration gives amount of ammonium carbonate produced;boiling leads to little or no reaction;enzyme is denatured;protein in nature;comparison of amount of product in A and C;comment on relative denaturation in A; 5 max

(d) A : less product formed;B : same result; 2

(e) pH, substrate, temperature (2 of 3); 2

(f) control of the variable missing in (e);use of replicates;stagger mixing times;perform simultaneous titrations;add inhibitor (boil immediately) to stop enzyme action; 3 max

[Total: 18]

2 (a) drawing: accurate number of bundles (between 12 and 18);different sizes shown;shown alternately – minimum 4 bundles;largest bundles have an elliptical shape;positions of both on arc; 5

(b) (i) accurate position of line on a radius, min. radial line acrosswhole length of bundle; 1(if a tangential line is drawn – be critical in its acceptance)

(ii) xylem / phloem in a bundle provided correct line above; 1

[Total: 7]

2001

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