Download and practise with this ZIMSEC O-Level Biology Paper 1 June 2023 question paper. Useful for exam revision, past paper practice, and preparation in Zimbabwe.
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This is the ZIMSEC O-Level Biology question paper for Paper 1 from June 2023. Use it for exam practice under timed conditions. The paper code is 4025/1.
# 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 …