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ZIMSEC A Level · 9190/1 · N2003

Biology Paper 1 November 2003

Questions
40
Syllabus code
9190/1

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Questions
40
Pass mark
24
Sit this paper

Answer every question in the printed order, get marked at the end, then see the answers.

The questions

Question 1

cell membranes

The diagram shows the fluid mosaic model of a membrane.

What is the name and function of molecule X?

  1. AName glycolipid, Function decreases membrane fluidity at high temperatures
  2. BName cholesterol, Function increases membrane fluidity at low temperatures
  3. CName glycolipid, Function decreases membrane fluidity at low temperatures
  4. DName cholesterol, Function increases membrane fluidity at high temperatures

Question 2

cell structure
Where in an animal cell is alcohol detoxified?
  1. AGolgi body
  2. Blysosomes
  3. Crough endoplasmic reticulum
  4. Dsmooth endoplasmic reticulum

Question 3

microscopy and magnification

The following diagrams show the main steps involved in measuring the width of a leaf at the midrib region using a light microscope.

If the smallest division on the stage graticule is 1mm long, what is the width of the leaf in micrometers?

  1. A3 500 μm.
  2. B2 500 μm.
  3. C56 μm.
  4. D3.5 μm.

Question 4

water
Which of the following properties of water allows homoiotherms to adapt to a range of environments?
  1. Auniversal solvent
  2. Bhigh surface tension
  3. Chigh heat capacity
  4. Dmaximum density at 4°C

Question 5

carbohydrates

The diagram represents a disaccharide.

What is the disaccharide and the type of bond between its monomer residues?

  1. AIdentity of disaccharide lactose, Bond between monomers 1 – 4 glycosidic
  2. BIdentity of disaccharide maltose, Bond between monomers 1 – 2 glycosidic
  3. CIdentity of disaccharide sucrose, Bond between monomers 1 – 4 glycosidic
  4. DIdentity of disaccharide lactose, Bond between monomers 6 – 2 glycosidic

Question 6

proteins
What is the theoretical number of different dipeptides that can be made using 20 different amino acids?
  1. A400
  2. B64
  3. C40
  4. D10

Question 7

enzymes
What is the temperature co-efficient of most enzyme-controlled reactions?
  1. A10.0
  2. B2.0
  3. C1.5
  4. D1.0

Question 8

enzymes

The diagram illustrates enzyme action.

What type of action is demonstrated?

  1. Acompetitive inhibition
  2. Birreversible inhibition
  3. Cinduced fit
  4. Dlock and key

Question 9

cell division
Which of the following statements is true about all cancer cells?
  1. AThey do not strongly adhere to each other therefore they can break and move freely in the body fluids.
  2. BThey require less energy to divide hence multiply at a fast rate.
  3. CThey continue to multiply only when they are tightly packed in the body.
  4. DIn culture media they eventually stop growing.

Question 10

meiosis
At which phase of meiosis does crossing over take place and which chromatids are involved?
  1. APhase prophase I, Chromatids involved non-sister chromatids
  2. BPhase prophase II, Chromatids involved sister chromatids
  3. CPhase metaphase I, Chromatids involved sister chromatids
  4. DPhase metaphase II, Chromatids involved non-sister chromatids

Question 11

protein synthesis
In what ways do polyribosomes make protein synthesis efficient?
  1. ADifferent protein molecules are made simultaneously from a single mRNA molecule.
  2. BEach copy of the same protein is made more rapidly.
  3. CSeveral mRNA copies are made at the same time.
  4. DSeveral copies of the same protein are made simultaneously from a single mRNA molecule.

Question 12

genetic engineering
Which of the following enzymes protect bacteria from foreign DNA?
  1. ADNA polymerase
  2. Bligase enzymes
  3. Chelicase enzymes
  4. Drestriction enzymes

Question 13

nucleic acids

The diagram illustrates complementary base pairing in a segment of DNA, where the small rectangles represent pyrimidines and large rectangles represent purines.

Which rectangle correctly identifies guanine?

  1. AA
  2. BB
  3. CC
  4. DD

Question 14

sex determination
From the chromosome sets of different male organisms shown, which male animal is homogametic?
  1. Adrosophilia 2n = 6 + XY
  2. Bgrasshopper 2n = 16 + XO
  3. Cman 2n = 44 + XY
  4. Dpheasant 2n = 14 + XX

Question 15

evolution

The following are the main assumptions of Darwin's theory of evolution through natural selection.

1 Variation exists within a population.
2 Carrying capacity is always constant.
3 Individuals which are better adapted survive to reproductive age.
4 Individuals have a tendency to over produce.

Which is a logical sequence of these assumptions in order to best explain the theory of evolution?

  1. A4 → 1 → 3 → 2
  2. B4 → 2 → 1 → 3
  3. C2 → 3 → 1 → 4
  4. D1 → 4 → 2 → 3

Question 16

selection

The graph shows the effect of temperature on the activity of three forms of a vital enzyme whose synthesis is controlled by two alleles designated R and S. The three possible genotypes RR, RS and SS lead to the three different enzyme forms whose response to temperature is as shown in the diagram.

When the mean annual temperature is 20°C for several years which of the following is correct?

  1. AThe heterozygotes and the homozygotes will have the same selective advantage.
  2. BAllele R will have the same frequency as allele S.
  3. CNo genotype will have a selective advantage.
  4. DThere will be complete dominance of R by S.

Question 17

photosynthesis
With reference to the substances given in the table, what are the immediate effects of removing carbon dioxide from chloroplasts which are exposed to light?
  1. AAdenosine triphosphate (ATP) no change, Ribulose biphosphate RuBp decreases, Phosphoglyceric acid (PGA) increases
  2. BAdenosine triphosphate (ATP) decreases, Ribulose biphosphate RuBp increases, Phosphoglyceric acid (PGA) no change
  3. CAdenosine triphosphate (ATP) no change, Ribulose biphosphate RuBp increases, Phosphoglyceric acid (PGA) decreases
  4. DAdenosine triphosphate (ATP) increases, Ribulose biphosphate RuBp increases, Phosphoglyceric acid (PGA) decreases

Question 18

respiration

The oxidation of triolein is shown by the following equation:

C₅₇H₁₀₄O₆ + 80O₂ → 57CO₂ + 52H₂O

What is the theoretical respiratory quotient (RQ) value for triolein?

  1. A52/57
  2. B80/57
  3. C57/80
  4. D52/80

Question 19

respiration
What is the main reaction which occurs during the Krebs cycle?
  1. Aoxidative decarboxylation
  2. Boxidative phosphorylation
  3. Cphotophosphorylation
  4. Dphotorespiration

Question 20

photosynthesis

DCPIP is decolourised when reduced and this can be used to demonstrate photosynthesis.

Which process directly leads to the reduction of the DCPIP?

  1. Aphotolysis
  2. Bconversion of GP to TP
  3. Ccyclic photophosphorylation
  4. Dnon-cyclic photophosphorylation

Question 21

transport of gases
Which substance in red blood cells acts as a buffer against low pH?
  1. Abicarbonate ions
  2. Bchloride ions
  3. Chaemoglobinic acid
  4. Doxy-haemoglobin

Question 22

transport in animals
Which tissue is present in the walls of both capillaries and arteries?
  1. Aconnective
  2. Belastic
  3. Cendothelial
  4. Dmuscle

Question 23

transport of gases
Which process is enzyme catalysed and occurs in the cytoplasm of red blood cells?
  1. Adissociation of carbonic acid, releasing carbonate ions
  2. Bdissociation of oxyhaemoglobin, releasing oxygen
  3. Creaction between carbon dioxide and haemoglobin forming carboaminohaemoglobin
  4. Dreaction between water and carbon dioxide forming carbonic acid

Question 24

transpiration
Which graph represents the relationship between the rate of transpiration of a mesophytic leaf and atmospheric humidity?
  1. AA
  2. BB
  3. CC
  4. DD

Question 25

the liver

The diagram summarises the breakdown of haemoglobin in the hepatocytes.

What happens to compounds P, Q and R?

  1. AP used in protein synthesis, Q excreted, R stored in muscles
  2. BP excreted, Q used in protein synthesis, R used in protein synthesis
  3. CP excreted, Q stored in muscles, R used in protein synthesis
  4. DP used in protein synthesis, Q excreted, R excreted

Question 26

nervous coordination

The diagram shows a cholinergic synapse.

Which of the following is correct about the position of acetylcholine receptors and the membrane which becomes hyper-polarised due to over stimulation?

  1. APosition of acetylcholine receptors 1, Hyper-polarised membrane m
  2. BPosition of acetylcholine receptors 2, Hyper-polarised membrane n
  3. CPosition of acetylcholine receptors 2, Hyper-polarised membrane m
  4. DPosition of acetylcholine receptors 1, Hyper-polarised membrane n

Question 27

homeostasis
Which graph correctly represents changes in the blood sugar levels of a diabetic person after drinking a glass of glucose solution?
  1. AA
  2. BB
  3. CC
  4. DD

Question 28

excretion

The graph represents the concentration of fluid within various parts of a nephron and the collecting duct into which it empties.

Which labelled portion is most likely to represent concentration within the loop of Henle?

  1. AA
  2. BB
  3. CC
  4. DD

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

conservation
Communal Areas Management Programme for Indigenous Resources (CAMPFIRE) is an example of conservation of biodiversity by
  1. Acreation of new habitats.
  2. Bmanagement of biodiversity.
  3. Cpreservation of existing biodiversity.
  4. Dreclamation of biodiversity.

Question 31

ecology

The table shows the results of a field study of four species in an ecosystem forming a food chain.

Species, Number of individuals, Dry mass of one Individual (arbitrary units), Energy value per unit mass (arbitrary units):
E, 2 500, 0.06, 0.01
F, 6, 1.5, 3
G, 300, 3, 0.02
H, 4, 10 000, 0.004

What is the correct food chain?

  1. AG → E → F → H
  2. BF → E → G → H
  3. CH → F → G → E
  4. DH → G → F → E

Question 32

plant reproduction
In angiosperms, through which part does the vascular strand of an ovule pass from the placenta?
  1. Aembryo sac
  2. Bfunicle
  3. Cinteguments
  4. Dmicropyle

Question 33

reproduction
What is the correct order in which hormones are released during the menstrual cycle? (First to Last)
  1. AFSH, oestrogen, progesterone
  2. BFSH, progesterone, oestrogen
  3. Cprogesterone, FSH, oestrogen
  4. Doestrogen, FSH, progesterone

Question 34

germination

The table gives the results of one experiment to find the effect of red light and darkness on breaking dormancy and the germination of raddish seeds.

Conditions before germination, Germination of type X seeds (%), Germination of type Y seeds (%):
Continuous red light, 79.8, 92
Continuous darkness, 70, 40
Alternate red light and darkness, 20, 35

What conclusion can be drawn from the results?

  1. ARed light has no effect on germination of type X seeds.
  2. BDarkness enhances effect of red light in both seeds.
  3. CRed light has a greater effect on germination of type Y seeds.
  4. DDarkness has no effect in both seeds.

Question 35

plant reproduction
Which of the following mechanisms favour out breeding in plants?
  1. Ahermaphrodite
  2. Bflower buds never open
  3. Cself-sterility
  4. Dstigma below anthers

Question 36

reproduction

The following events occur during fertilization in humans:

1 lysosomes are released into the zona pellucida
2 protease and hyaluronidase enzymes are released
3 glycoproteins on the surface of the sperm are digested
4 second meiotic division is completed

Which is the correct sequence in which these events occur during fertilization?

  1. A2 → 3 → 4 → 1
  2. B3 → 2 → 1 → 4
  3. C1 → 3 → 2 → 4
  4. D3 → 4 → 2 → 1

Question 37

gaseous exchange
Which of the following describes the changes to the epithelial lining of the airways during the development of chronic bronchitis?
  1. ACilia are destroyed.
  2. BGoblet cells produce less mucus.
  3. CMucus glands become smaller.
  4. DEpithelial lining becomes thinner.

Question 38

gaseous exchange

During exercise, the tidal volume of a person increased to 1.3dm³ and the breathing rate was 20 breaths for every 30 seconds.

What volume of air was taken into the lung in one minute?

  1. A78 dm³
  2. B52 dm³
  3. C39 dm³
  4. D26 dm³

Question 39

classification
What is the common feature about the body plan of chordates and cnidarians?
  1. Aan endoderm lining the enteron
  2. Bbilateral symmetry
  3. Ca mouth and an anus
  4. Dtriploblastic

Question 40

classification

The diagram shows the life cycle of a plant in which the sporophyte is the dominant generation.

Which plant group is represented by this cycle?

  1. Aalgae
  2. Bbryophytes
  3. Cpteridophytes
  4. Dspermatophytes

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