ZIMSEC O-Level Biology Paper 1 June 2023 Question Paper

PAPER 1 Jun 2023

Question 1

An experiment that produces a poisonous gas should be conducted in a

A classroom with closed windows.

B storeroom away from pupils.

C laboratory with work benches.

D well ventilated open space.

Question 2

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?

A \(2 \longrightarrow 1 \longrightarrow 3 \longrightarrow 4\)

B \(1 \longrightarrow 2 \longrightarrow 3 \longrightarrow 4\)

C \(3 \longrightarrow 1 \longrightarrow 2 \longrightarrow 4\)

D \(4 \longrightarrow 1 \longrightarrow 3 \longrightarrow 2\)

Question 3

Which one is a function of lipids in living organism?

A formation of antibodies

B source of water

C regulation of pH

D clotting of blood

Question 4

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

A lipid.

B protein.

C nucleic acid.

D carbohydrate.

Question 5

Cell walls are responsible for

A cell division.

B generating energy.

C structural support.

D trapping sunlight.

Question 6

What is the likely effect of removing mitochondria from a plant cell?

| A | plasmolysis stops | | :--- | :--- | | B | metabolism stops | | C | osmosis stops | | D | diffusion stops |

Question 7

The diagram shows an animal cell.

The cell is specialised for

A absorbing water.

B engulfing bacteria.

C transmitting impulses.

D transporting oxygen.

Question 8

A biological washing powder was added to water at \(60^{\circ} \mathrm{C}\). The enzymes in the powder were

A activated.

B inactivated.

C denatured.

D saturated.

Question 9

What are the subunits of enzymes?

A glucose

B amino acids

C fatty acids

D glycerol

Question 10

Which biological molecule determines the structure of insulin?

A protein

B lipid

C DNA

D vitamins

Question 11

In plants, phosphorus is needed for

A chlorophyll formation.

B ATP formation.

C fruit formation.

D flower formation.

Question 12

Which one is a characteristic of seeds dispersed by water?

A seeds with wing like parts

B seeds with fine hairs

C seeds with fibrous coat

D seeds with hooks

Question 13

Plants may wilt due to low

A humidity.

B temperature.

C wind speed.

D light intensity.

Question 14

The diagram shows a transverse section of a dicotyledonous root. Which tissue, A, B, C or D, is the xylem?

Question 15

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

A midnight when photosynthesis is lowest.

B sunrise when respiration rate reduces.

C midday when light intensity is brightest.

D sunset when temperatures start dropping.

Question 16

The raw materials for photosynthesis are

A water and oxygen.

B water and carbon dioxide.

C glucose and oxygen.

D glucose and carbon dioxide.

Question 17

Which component of tobacco smoke paralyses cilia?

A tar

B nicotine

C carbon monoxide

D carbon dioxide

Question 18

In the human kidney, the highest concentration of urea is in the

A artery.

B cortex.

C medulla.

D ureter.

Question 19

The diagram shows the structure of the mammalian heart.

Which pair of blood vessels carry oxygenated blood?

A 1 and 2

B 1 and 4

C 2 and 3

D 3 and 4

Question 20

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?

Question 21

The diagram shows the structure of a tooth. Which part, A, B, C or D, contains nerves and blood vessels.

Question 22

The diagram shows a part found in the inner ear.

What is the role of the part labelled \(\mathbf{X}\)?

A responds to air vibrations by moving backwards and forwards

B focuses on near and distant objects

C responds to high and low frequency sounds

D responds to light and sends impulses to the brain

Question 23

Assimilation is

A taking food into the digestive system.

B muscular churning of food in the stomach.

C the absorption of digested food molecules from the ileum.

D making use of absorbed food molecules in metabolic processes.

Question 24

The role of aerobic respiration is to

A breakdown ATP.

B produce carbon dioxide.

C produce alcohol.

D synthesize ATP.

Question 25

The diagram shows a section through the human brain. Which part, A, B, C or D, maintains balance?

Question 26

The diagram shows fermentation of sugar by yeast.

What gas is X?

A oxygen

B carbon monoxide

C carbon dioxide

D nitrogen

Question 27

Viruses can be viewed using

A light microscopes.

B electron microscopes.

C bio viewers.

D hand lens.

Question 28

Which characteristic is common to all microorganisms?

A they cause diseases

B they are decomposers

C they are unicellular

D they contain genetic material

Question 29

Which condition is not a result of gene mutation?

A albinism

B Down's syndrome

C haemophilia

D sickle cell anaemia

Question 30

Which feature is an example of continuous variation?

A intelligence

B tongue rolling

C earlobes

D sex

Question 31

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?