For exam. use 1 Scale to

Name:

Section A : [40 marks]

SMJK Perempuan China Pulau Pinang

STPM Trial Examination 2009

BIOLOGY Paper 2

Time : 2 Yo hours

Answer all the questions in this section.

100% Paper 1 x2

Paper 2: Section A Section B

Ting. U6S_

1. Table 1.1 below shows the relative amounts of bases adenine, thymine, guanine and cytosine in DNA from different organisms.

Source Adenine Thymine Guanine Cytosine Bacterium 23.8 23.1 26.8

126

.3

Maize 26.8 27.2 22.8 1

23.2

Drosophila 30.7 29.5 19.6 20.2

Chicken 28.0 28.4 22.0 21.6

Human 29.3 30.0 20.7 20.0

Table 1. 1

a) Analyze the table given.

i) Based on the infor'T'ation from the table, what can you deduce about the ratio of the bases. (1)

ii) State the importance of your deduction to the structure of DNA. (2)

I

Diagram 1 shows a protein synthesis process occurring in an eukaryotic cell.

x

:)l fl r J .~.

':1.:1 tt'l' in(' ac d ,"-Iel \ ·l ctl")i;)ni"'C'

y Diagram 1

b) On the diagram, label the following :

i) 5' and 3' end of DNA and mRNA. (1)

ii) Transcribing (sense) and non-transcribing (antisense) strands. (1)

c) Define processes X and Y (2)

d) Explain what happens in steps I, II and III. (3)

2. Diagram 2 shows an outline of the main stages in the Calvin cycle.

RuBP

GP (PGA)

regeneration of

RuBP

Diagram 2

TP (PGAL)

a) State precisely where the Calvin cycle occurs. (1) ______________ _

b) Complete Diagram Z to show where the following occur: (5)

i) CO, fixation ii ATP is converted to ADP iii Reduced NADP is oxidized iv Glucose is synthesised

c) Enzyme X IS needed in the b) i) process above .

i) Identify enzyme X. (1) _________ __________________ _

ii) Explain the relationship between the low efficiency of photosynthesis in C, plants during low concentration of C02 with reference to enzyme X. (3)

3. In an investigation into the flowering of a variety of tobacco, different light and dark treatments were carried out.

Diagram 3 shows six different light and dark treatments given to the said lant over several 24-hour eriods.

Peri ",i11O II r

8 Ie 10 20 24

A Non- Ilowerin g

B rlowering

<I L-___ _ !'i 011- t1 0 I>. eri n g.

R : red light FR : far red light

Diagram 3

Ii 4

D

E

f

Pcriod/hollr

12 10 ,0 24 .. '

Critical night lellb>th

G; ) Predict, for treatment D, E and F shown in Diagram 3, whether flowering would occur in the plant In each case, give a reason for your answer. (6)

Treatment Prediction Reason

D

E

F

~ . The graph~below shC'\'>' the effect of the concentration of two phytohormones (plant hormones), A and B on the growth of a species of plant.

E E

60

50 -

.c 40

!30~ o I 1:: 20 .., ~ ,

I O~ o -t""'--;,--.I----,!-r·--r---i-..

10 4 10 :! 10 ' Hi ' 10' l C~

Phytohormone A concentration! ~, ~ Inrn '

b) Identify phytohormones A and B (1)

A: ------------------------ B:

60

50 E E 1! 40

Lo Lo ' ~J

.. ' - -+-- ..--o r-r I ,--..

o 0.2 0.4 0 .6 O.B 1.0 1.2 PhytOhormone B concentra Tloni Jig mm '

------------------------c) Explain how farmers can use phytohormones A and B to produce seedless fru its. (3)

4. Diagram 4 represents a female human cell with only the sex chromosome pair is shown in the cell.

, , \,' \, .'

, ' I

~X ; , Xiii

i ! ! 1 \ J ' . ...-

Diagram 4

a) State what is meant by non-disjunction, (1)

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b) The cell mentioned above undergoes meiosis. If non-disjunction of sex chromosomes occurs only during meiosis I, draw and label the end product of meiosis I. (1)

c) If non-disjunction of the sex chromosomes occurs only during meiosis II , draw two types of gametes that may form. (1)

d) With reference to b) , if the gamete with the lesser chromosomes is fertili zed by a normal X sperm, i) draw the result of the fertilization . (Tip : autosomes need not be drawn) (1) i) state the abnormali ties (syndrome) that will be inherited by the progeny produced. (1) ii) State ON E major characteristic that will be observed in the progeny. (1)

i) Result of fertilization:

! )

ii)) Abn ormality :

iii) Major Ch2racteristic :

I e) In another unrelated case, referring to c) If the gamete w ith the most chromosomes is fertilized by a normal Y sperm,

I) draw the resu lt of the fertilization. (Tip: autosomes need not be drawn) (1) ii) state the abnormalities (syndrome) that will be inherited by the progeny produced. (1)

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iii) State ONE major characteristic that wi ll be observed in the progeny. (1)

i) Result of fertiliza tion :

( )

I ii ) Abnormality :

iii) Major Characteristic:

I

e) Non-disjunction is sometimes induced in plants. Give one reason why th is is done. (1)

Section B: (60 marks)

Answer any four questions from this section.

5. a) 'Prokaryotic and eukaryotic cells are different with respect to s ize & structural organization'. Explain what is meant by this statement. (5)

b) Discuss the extent to which the angiospermophytes and filicinophytes are adapted to life on land . (1 0)

6. a) In mice, coat colour is determined by the action of genes at several different loci. A mutant allele at one coat-colour locus produces an unpigmented coat. The usual allele at this locus produces a pigmented coat. Pure-breeding pigmented mice were crossed with pure-breeding unpigmented mice. Their offspring were mated.

i) Draw a genetic diagram to explain these crosses up to F2, using A for normal pigmentation alle le and a for the unpigmented allele. (4)

In the F2 generation, the actua l numbers were 141 pigmented and 59 unpigmented mice .

ii) Run and detail a:\'.2 (chi-square) test to determine if these results supports your pred iction from a i). Use the following 'Ie probability table to help you . (6)

nip .80 .70 .50 .30 .20 .10 .05 .02 .01

1 .064 .148 .455 1.074 1.642 2.706 3.841 5.142 6.635 , 2 .446 .713 1.386 2.408 3.219 4.605 5.991 7.824 9.210

3 \ 1005 1.424 2.366 3.665 4.642 6.251 7.815 9.837 11 .341

4 1.649 2·195 3.357 4.878 5.989 7.779 9.488 11 .668 13.277

b) Name three pharmaceutical products obta ined by using recombinant DNA technology. (3)

c) Why is it that patients using recombinant DNA pharmaceutical products would unlikely to suffer from allergic reactions? (2)

7. a) Using adrenaline as an example, explain how non-steroid hormone acts. (11)

b) Suggest how chemical compounds based on the following act to prevent pregnancy. (4)

i) oestrogen ii ) progesterone

8. a) Exp lain how resting potential and action potential is generated on an axon. (8)

b) State the mechanism present in the nerves that allow only unidirectional impulses and prevents fatigue. (7)

9. a) Explain briefly the following ecological terms:

i) Biotic potential (3) ii) Environmental resistance (3) iii) Carrying capacity (3)

b) Describe how the population size of a named animal in a named habitat can be estimated. (6)

10. Three types of natural selection can occur in any natural population. Using suitable examples, discuss all three. (15)

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