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ZIMSEC O Level · 4025/1 · J2023

Biology Paper 1 June 2023

Questions
40
Time allowed
60 min
Syllabus code
4025/1

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Questions
40
Pass mark
24
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Answer every question in the printed order, get marked at the end, then see the answers.

The questions

Question 1

Laboratory safety
An experiment that produces a poisonous gas should be conducted in a
  1. Aclassroom with closed windows.
  2. Bstoreroom away from pupils.
  3. Claboratory with work benches.
  4. Dwell ventilated open space.

Question 2

Laboratory safety

The list shows fire drill steps arranged in random order.

1. exit building in a calm and orderly manner
2. assembly at a safe place
3. sound an alarm bell
4. take a roll call

What is the correct order of the steps?

  1. A2, 1, 3, 4
  2. B1, 2, 3, 4
  3. C3, 1, 2, 4
  4. D4, 1, 3, 2

Question 3

Biological molecules
Which one is a function of lipids in living organism?
  1. Aformation of antibodies
  2. Bsource of water
  3. Cregulation of pH
  4. Dclotting of blood

Question 4

Biological molecules

A substance consists of the elements carbon, hydrogen, oxygen, nitrogen and sulphur.

The substance is a

  1. Alipid.
  2. Bprotein.
  3. Cnucleic acid.
  4. Dcarbohydrate.

Question 5

Cell structure
Cell walls are responsible for
  1. Acell division.
  2. Bgenerating energy.
  3. Cstructural support.
  4. Dtrapping sunlight.

Question 6

Cell structure
What is the likely effect of removing mitochondria from a plant cell?
  1. Aplasmolysis stops
  2. Bmetabolism stops
  3. Cosmosis stops
  4. Ddiffusion stops

Question 7

Cells and tissues

The diagram shows an animal cell.

The cell is specialised for

  1. Aabsorbing water.
  2. Bengulfing bacteria.
  3. Ctransmitting impulses.
  4. Dtransporting oxygen.

Question 8

Enzymes

A biological washing powder was added to water at 60 degrees Celsius.

The enzymes in the powder were

  1. Aactivated.
  2. Binactivated.
  3. Cdenatured.
  4. Dsaturated.

Question 9

Enzymes
What are the subunits of enzymes?
  1. Aglucose
  2. Bamino acids
  3. Cfatty acids
  4. Dglycerol

Question 10

Genetics
Which biological molecule determines the structure of insulin?
  1. Aprotein
  2. Blipid
  3. CDNA
  4. Dvitamins

Question 11

Plant nutrition
In plants, phosphorus is needed for
  1. Achlorophyll formation.
  2. BATP formation.
  3. Cfruit formation.
  4. Dflower formation.

Question 12

Reproduction in plants
Which one is a characteristic of seeds dispersed by water?
  1. Aseeds with wing like parts
  2. Bseeds with fine hairs
  3. Cseeds with fibrous coat
  4. Dseeds with hooks

Question 13

Transpiration
Plants may wilt due to low
  1. Ahumidity.
  2. Btemperature.
  3. Cwind speed.
  4. Dlight intensity.

Question 14

Transport in plants

The diagram shows a transverse section of a dicotyledonous root.

Which tissue, A, B, C or D, is the xylem?

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

Question 15

Photosynthesis

The concentration of carbon dioxide in the air around a plant is measured over a 24 hour period starting at midnight.

The lowest concentration of carbon dioxide will be measured at

  1. Amidnight when photosynthesis is lowest.
  2. Bsunrise when respiration rate reduces.
  3. Cmidday when light intensity is brightest.
  4. Dsunset when temperatures start dropping.

Question 16

Photosynthesis
The raw materials for photosynthesis are
  1. Awater and oxygen.
  2. Bwater and carbon dioxide.
  3. Cglucose and oxygen.
  4. Dglucose and carbon dioxide.

Question 17

Health and disease
Which component of tobacco smoke paralyses cilia?
  1. Atar
  2. Bnicotine
  3. Ccarbon monoxide
  4. Dcarbon dioxide

Question 18

Excretion
In the human kidney, the highest concentration of urea is in the
  1. Aartery.
  2. Bcortex.
  3. Cmedulla.
  4. Dureter.

Question 19

Transport in animals

The diagram shows the structure of the mammalian heart.

Which pair of blood vessels carry oxygenated blood?

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

Question 20

Transport in animals

The bar graph shows the concentration of oxygen in blood sampled at four different places in the circulatory system of a mammal.

Which blood sample was taken from a pulmonary vein?

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

Question 21

Nutrition

The diagram shows the structure of a tooth.

Which part, A, B, C or D, contains nerves and blood vessels.

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

Question 22

Coordination

The diagram shows a part found in the inner ear.

What is the role of the part labelled X?

  1. Aresponds to air vibrations by moving backwards and forwards
  2. Bfocuses on near and distant objects
  3. Cresponds to high and low frequency sounds
  4. Dresponds to light and sends impulses to the brain

Question 23

Digestion
Assimilation is
  1. Ataking food into the digestive system.
  2. Bmuscular churning of food in the stomach.
  3. Cthe absorption of digested food molecules from the ileum.
  4. Dmaking use of absorbed food molecules in metabolic processes.

Question 24

Respiration
The role of aerobic respiration is to
  1. Abreakdown ATP.
  2. Bproduce carbon dioxide.
  3. Cproduce alcohol.
  4. Dsynthesize ATP.

Question 25

Coordination

The diagram shows a section through the human brain.

Which part, A, B, C or D, maintains balance?

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

Question 26

Respiration

The diagram shows fermentation of sugar by yeast.

What gas is X?

  1. Aoxygen
  2. Bcarbon monoxide
  3. Ccarbon dioxide
  4. Dnitrogen

Question 27

Classification
Viruses can be viewed using
  1. Alight microscopes.
  2. Belectron microscopes.
  3. Cbio viewers.
  4. Dhand lens.

Question 28

Classification
Which characteristic is common to all microorganisms?
  1. Athey cause diseases
  2. Bthey are decomposers
  3. Cthey are unicellular
  4. Dthey contain genetic material

Question 29

Genetics
Which condition is not a result of gene mutation?
  1. Aalbinism
  2. BDown's syndrome
  3. Chaemophilia
  4. Dsickle cell anaemia

Question 30

Variation
Which feature is an example of continuous variation?
  1. Aintelligence
  2. Btongue rolling
  3. Cearlobes
  4. Dsex

Question 31

Genetics
A man with a recessive sex linked allele is married to a normal woman.
What is the probability of the allele passing on to his daughter?
  1. A25%
  2. B50%
  3. C75%
  4. D100%

Question 32

Genetics

The diagram shows a chromosome.

The part labelled X is called the

  1. Anucleolus.
  2. Bchromatid.
  3. Ccentromere.
  4. Dallele.

Question 33

Genetics
Complete dominance is when
  1. Adifferent alleles have an equal effect on the phenotype of the offspring.
  2. Ban allele expresses in the phenotype even in the presence of an alternative.
  3. Ccontrasting alleles are combined in an individual organism.
  4. Da gene has more than two contrasting alleles.

Question 34

Classification
A multi-cellular organism that has hyphae belongs to kingdom
  1. AAnimalia.
  2. BFungi.
  3. CPlantae.
  4. DProtista.

Question 35

Soil
Which one leads to degradation of soil?
  1. Amulching garden beds
  2. Bpracticing mixed cropping
  3. Cadding manure to soil
  4. Dploughing along slopes

Question 36

Ecology
Which human activity is a way of managing ecosystems?
  1. Alivestock rearing
  2. Bcrop farming
  3. Cmarket gardening
  4. Dplanting trees

Question 37

Soil

The pie-chart shows components of a 50 g soil sample.

What is the mass of organic matter?

  1. A4.2 g
  2. B8.3 g
  3. C30 g
  4. D42 g

Question 38

Health and disease
Liver and spleen enlargement are symptoms of
  1. Abilharzia.
  2. Btyphoid.
  3. Cmalaria.
  4. Dcholera.

Question 39

Health and disease
Which disease is associated with excessive alcohol consumption?
  1. Akidney failure
  2. Bliver cirrhosis
  3. Clung cancer
  4. Dtuberculosis

Question 40

Health and disease
Which one is a method of preventing malaria?
  1. Aavoiding overcrowded conditions
  2. Bproviding access to clean water
  3. Cprovision of a balanced diet
  4. Dintroducing fish into ponds

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