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ZIMSEC A Level · 9190/1 · J2004

Biology Paper 1 June 2004

Questions
38
Syllabus code
9190/1

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Questions
38
Pass mark
23
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Answer every question in the printed order, get marked at the end, then see the answers.

The questions

Question 1

cell structure
Which of the following groups of structures would be clearly seen in a well stained onion epidermal cell under the light microscope at ×400 magnification?
  1. Amitochondria, nuclei, plasma membrane
  2. Bnucleoli, starch grains, protoplasm
  3. Cnuclei, Golgi apparatus, mitochondria
  4. Dendoplasmic reticulum, plasma membrane, starch grains

Question 2

cell membranes
What property of phospholipids makes them ideal in membrane architecture?
  1. Aability to form micelles
  2. Bpossession of hydrophobic tails
  3. Cpossession of hydrophobic heads
  4. Dinsolubility in water

Question 3

microscopy and magnification
On an electron micrograph whose magnification is ×9600, a nucleus measures 58 mm. What is the actual size of the nucleus in μm?
  1. A0.006
  2. B6.040
  3. C0.165
  4. D5568

Question 4

lipids
A triglyceride has
  1. Aone glycerol molecule, three fatty acid residues.
  2. Bone glycerol molecule, two fatty acid residues.
  3. Cthree glycerol molecules, one fatty acid residue.
  4. Dthree glycerol molecules, three fatty acid residues.

Question 5

water
Which orientation is likely to favour hydrogen bond formation between water molecules?
  1. AA
  2. BB
  3. CC
  4. DD

Question 6

amino acids and buffering

The diagram illustrates the buffering effect of an amino acid at pH 5.6.

Which pH conditions are likely to be correct for Y and Z?

  1. AY 8.2, Z 5.6
  2. BY 4.8, Z 6.2
  3. CY 7.0, Z 8.2
  4. DY 6.2, Z 7.0

Question 7

enzymes
Which of the following statements is correct about enzymes as proteins?
  1. AThey speed up the rate of chemical reactions.
  2. BThey are destroyed by excess heat.
  3. CThey do not take part in the reaction.
  4. DThey catalyse reversible reactions.

Question 8

enzymes

The diagram shows an energy profile for a reversible reaction with and without an enzyme.

Which of the following gives the activation energy of the reverse reaction with an enzyme?

  1. AX
  2. BY
  3. CX + Z
  4. DY + Z

Question 9

meiosis
During which stage of meiosis are homologous chromosomes separated?
  1. Aanaphase 1
  2. Banaphase 2
  3. Cprophase 1
  4. Dprophase 2

Question 12

nucleic acids

The following diagram shows a single DNA strand.

Which is the direction of the strand as indicated by the arrow and the type of bond represented at X?

  1. Adirection of strand 3¹ – 5¹, bond at X phosphoester
  2. Bdirection of strand 3¹ – 5¹, bond at X hydrogen
  3. Cdirection of strand 5¹ – 3¹, bond at X phosphoester
  4. Ddirection of strand 5¹ – 3¹, bond at X hydrogen

Question 13

DNA replication
Bacteria were grown for several generations in a medium containing ¹⁵N. Some of the resulting bacteria were then grown in ¹⁴N for one generation. Which test tube shows the position of first generation DNA in the density gradient?
  1. AA
  2. BB
  3. CC
  4. DD

Question 14

inheritance
Which parental phenotypes would produce offsprings with blood groups A and B only?
  1. Ablood group of mother A, blood group of father B
  2. Bblood group of mother AB, blood group of father AB
  3. Cblood group of mother AB, blood group of father B
  4. Dblood group of mother AB, blood group of father O

Question 15

selection
Which of the following is an example of artificial selection?
  1. Aproduction of resistant varieties of plants using polyploidy
  2. Bloss of genetic diversity due to volcanic activity
  3. Cresistance of bacteria to penicillin
  4. Dsurvival of xerophytes during drought

Question 16

inheritance

The table below shows the results of self-crossing tall, purple flowered plants.

Flower colour, numbers of plants:
Tall plants: Red 73, Purple 157, white 67
Dwarf: Red 21, Purple 53, white 25

When self-fertilised which group of offsprings will only produce identical plants?

  1. Adwarf, purple flowered
  2. Btall, white flowered
  3. Cdwarf, white flowered
  4. Dtall, red flowered

Question 17

photosynthesis
Which sequence correctly portrays the flow of electrons during photosynthesis?
  1. AH₂O → NADPH → TP
  2. BH₂O → PSI → PSII
  3. CO₂ → PSII → PSI
  4. DNADPH → PSII → PSI

Question 18

photosynthesis
The diagram shows the anatomy of C₄ plants. Where does the Calvin Cycle occur?
  1. AA
  2. BB
  3. CC
  4. DD

Question 19

respiration

The graph below shows how gaseous exchange in two organisms X and Y varies with temperature.

Which statement is correct about the changes in respiratory quotient (RQ) values of the two organisms with temperature?

  1. AY has a higher RQ value than X.
  2. BThe RQ value of Y is always greater than one.
  3. CThe RQ value of X is smaller at lower temperatures than at higher temperatures.
  4. DThe RQ of Y increases with temperature at lower temperatures.

Question 20

respiration

Four tubes containing extracts from animal tissue were prepared as shown.

tube 1: glucose + homogenised cells
tube 2: glucose + mitochondria
tube 3: glucose + cytoplasm lacking organelles
tube 4: glucose + distilled water

After incubation for 48 hours, in which tubes would glucose be used up ?

  1. A1 and 2
  2. B1 and 3
  3. C2 and 3
  4. D3 and 4

Question 21

the heart
Which of the following occurs during ventricular systole in a mammalian heart?
  1. Aventricular pressure increases
  2. Bventricular volume increases
  3. Cbicuspid valve opens
  4. Daortic pressure decreases

Question 22

the heart
Which of the following correctly represents the effect of increasing pH and increasing temperature on heart rate?
  1. Aincrease in pH: heart rate increases; increase in temperature: heart rate decreases
  2. Bincrease in pH: heart rate decreases; increase in temperature: heart rate decreases
  3. Cincrease in pH: heart rate decreases; increase in temperature: heart rate increases
  4. Dincrease in pH: heart rate increases; increase in temperature: heart rate increases

Question 23

transport in plants
The diagram illustrates the mechanism by which sucrose is loaded into companion cells. Which process is coupled to ATP hydrolysis?
  1. AA
  2. BB
  3. CC
  4. DD

Question 24

water

Which combination of properties of water listed is important in the movement of water through a plant as well as the cooling effect of transpiration?

1 high specific heat capacity
2 high latent heat of vaporisation
3 high tensile strength
4 high surface tension
5 low viscosity
6 maximum density at 4°C

  1. A1 2 3 6
  2. B1 3 4 5
  3. C1 4 5 6
  4. D2 3 4 5

Question 25

excretion
Which process utilises most of the ATP in the nephron?
  1. Aactive reabsorption of sodium ions in the distal convoluted tubule using aldosterone
  2. Bactive unloading of sodium and chloride ions in the thick ascending limb of the hoop of Henle
  3. Ctubular secretion of hydrogen ions into the glomerular filtrate
  4. Dactive loading of sodium ions and glucose into the proximal convoluted cells

Question 26

nervous coordination
Which statement correctly explains why action potentials are usually propagated in only one direction?
  1. ANodes of Ranvier only conduct in one direction.
  2. BIons can only flow along the axon in one direction.
  3. CSodium and potassium voltage sensitive gates open in one direction.
  4. DThe brief refractory period prevents depolarisation in the opposite direction.

Question 27

homeostasis

The diagram below shows some of the organs involved in the homeostatic control of glucose in humans.

Which combination of processes correctly identifies W, X, Y and Z?

  1. AW glycogenesis, X gluconeogenesis, Y absorption, Z ultra filtration
  2. BW ultra filtration, X glycogenesis, Y glycogenolysis, Z absorption
  3. CW absorption, X gluconeogenesis, Y glycogenesis, Z ultra filtration
  4. DW gluconeogenesis, X absorption, Y ultra filtration, Z glycogenesis

Question 28

homeostasis
Which set correctly shows the secretions of the different cells of the pancreas?
  1. Aacinar cells digestive enzymes, alpha cells insulin, beta cells glucagon
  2. Bacinar cells insulin, alpha cells digestive enzyme, beta cells glucagon
  3. Cacinar cells digestive enzymes, alpha cells glucagon, beta cells insulin
  4. Dacinar cells glucagon, alpha cells insulin, beta cells digestive enzymes

Question 29

ecology
In which of the following ecological units would you expect the greatest competition between two species?
  1. Acommunity
  2. Becosystem
  3. Chabitat
  4. Dniche

Question 30

ecology
The addition of excess nitrogen containing fertilizer to soil results in eutrophication. What creates a biochemical oxygen demand (B.O.D) in water?
  1. Adeath of aquatic organisms like fish
  2. Balgal blooms
  3. Ca reduction in light penetrating through waters
  4. Da rise in biomass of decomposers

Question 31

ecology

The concentration of a non-biodegradable pesticide in the tissues of five organisms in a food chain was measured and presented in the table shown.

Organisms, Concentration of pesticide (arbitrary units):
J 100
K 2 000
L 1 600
M 400
N 700

Identify the organisms in the food chain which involve cabbage, aphid, small bird, hawk and wild cat.

  1. AJ aphid, K hawk, L wild cat, M cabbage, N small bird
  2. BJ cabbage, K small bird, L hawk, M wild cat, N aphid
  3. CJ cabbage, K wild cat, L hawk, M small bird, N aphid
  4. DJ cabbage, K wild cat, L hawk, M aphid, N small bird

Question 32

photoperiodism
If a long-day plant has a critical night length of 10 hours which of the following 24 hour cycle would prevent flowering?
  1. A13 hours light / 11 hours dark
  2. B15 hours light/ 9 hours dark
  3. C3 hours light / 9 hours dark /3 hours light then 9 hours dark
  4. D9 hours light / 3 hours dark / 9 hours light and 3 hours dark

Question 33

plant reproduction
The diagram shows part of a carpel of a flower. Which part is diploid?
  1. AA
  2. BB
  3. CC
  4. DD

Question 34

reproduction
During which phase of the ovarian cycle do the levels of (luteinising hormone) LH and (follicle stimulating hormone) FSH reach a peak?
  1. Athe period surrounding ovulation
  2. Bthe flow phase of the menstrual cycle
  3. Cthe follicular phase
  4. Dthe end of luteal phase

Question 35

growth and development

The graphs show the growth rate curves of the brain, the gonads and the thymus drawn relative to the absolute growth curve of the whole body for a human being.

Which of the following correctly identifies the relative growth curves of the brain, the reproductive organs and the thymus gland?

  1. ABrain 1, Gonads 2, Thymus 3
  2. BBrain 3, Gonads 1, Thymus 4
  3. CBrain 2, Gonads 4, Thymus 1
  4. DBrain 4, Gonads 3, Thymus 2

Question 36

germination

The graph shows the effect of temperature on the germination of seeds of the plant, yellow rocket (Barbarea vulgarism), kept in either light or darkness.

What conclusion can be drawn from the results of this experiment on the germination of yellow rocket?

  1. ASeeds exposed to light germinate at higher temperatures.
  2. BSeeds exposed to light germinate at lower temperatures.
  3. CSeed germination is not affected by the presence of light or by temperature.
  4. DGermination is greater when seeds are germinated in darkness.

Question 37

gaseous exchange
The diagram shows a microscopic section through a tracheal wall. Which part represents cartilage?
  1. AA
  2. BB
  3. CC
  4. DD

Question 38

gaseous exchange
Why does an athlete continue to breathe hard after a long race?
  1. AHe has to restore the optimal concentration of oxygen in the blood.
  2. BHe needs to breathe out the carbon dioxide produced during running.
  3. CHe takes some time to slow the breathing.
  4. DHe has to lower his body temperature which has been raised considerably during running.

Question 39

classification
Which of the following organisms has bilateral symmetry?
  1. AA
  2. BB
  3. CC
  4. DD

Question 40

classification
The table shows how features evolve in the animal kingdom. Which set of features is typical of the phylum nematoda?
  1. ABody plan none, Symmetry none, Body Cavity acoelomate, Segmentation absent
  2. BBody plan sac plan, Symmetry radial, Body Cavity acoelomate, Segmentation absent
  3. CBody plan tube within tube, Symmetry bilateral, Body Cavity pseudo coelom, Segmentation absent
  4. DBody plan tube within tube, Symmetry true coelum, Body Cavity true coelon, Segmentation present

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