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Question 1

Topic: 1.1

What are characteristics of all living organisms?

A. breathing, growth and movement B. egestion, nutrition and reproduction C. digestion, excretion and respiration D. reproduction, respiration and sensitivity

▶️ Answer/Explanation

Solution

Ans: D

The key characteristics of all living organisms are summarized by MRS GREN: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition. Option D includes three of these fundamental characteristics (reproduction, respiration, and sensitivity), making it the most comprehensive correct answer.

Question 2

Topic: 1.2

Using the binomial system, the name of a lion is Panthera leo.

Which statement is correct?

A. The lion belongs to the kingdom Panthera. B. The lion belongs to the genus Panthera. C. The lion belongs to the species Panthera. D. The lion belongs to the genus leo.

▶️ Answer/Explanation

Solution

Ans: B

In binomial nomenclature, the first name (Panthera) represents the genus, and the second name (leo) represents the species. Therefore, the lion belongs to the genus Panthera, making option B correct. The other options either confuse the taxonomic levels or misplace the names.

Question 3

Topic: 1.3

Which feature would place organisms into the crustacean group of arthropods?

A. eight legs B. six legs C. two pairs of antennae D. usually have two pairs of wings

▶️ Answer/Explanation

Solution

Ans: C

Crustaceans are distinguished from other arthropods by having two pairs of antennae. Eight legs (A) is characteristic of arachnids, six legs (B) is typical of insects, and wings (D) are found only in insects among arthropods.

Question 4

Topic: 2.1

The diagram shows the structure of a palisade cell from a leaf.

Which structure contains chlorophyll?

▶️ Answer/Explanation

Solution

Ans: C

Chlorophyll is the green pigment found in chloroplasts, which are responsible for photosynthesis. In a palisade cell (specialized for photosynthesis), the chloroplasts would be the structures containing chlorophyll. Without seeing the diagram, we know from the mark scheme that C represents the chloroplasts.

Question 5

Topic: 2.2

A bacterial cell has a length of 40 mm when it is magnified by ×20 000.

What is the actual length of the bacterial cell?

A. 0.0002 mm B. 0.002 mm C. 0.02 mm D. 0.2 mm

▶️ Answer/Explanation

Solution

Ans: B

To find the actual size, divide the magnified size by the magnification: 40 mm ÷ 20,000 = 0.002 mm. This calculation shows the real length of the bacterial cell is 0.002 mm, making option B correct.

Question 6

Topic: 3.2

Which diagram shows the appearance of a plant cell after it is placed in pure water?

▶️ Answer/Explanation

Solution

Ans: D

When a plant cell is placed in pure water, water enters by osmosis causing the cell to swell. The cell wall prevents bursting, resulting in a turgid cell (D). Other options show cells that are either plasmolyzed, normal, or burst – which don’t occur in plant cells in pure water.

Question 7

Topic: 3.1

What would lead to a decrease in diffusion rate into a cell?

A greater concentration gradient B higher temperature C larger surface area of cell D thicker cell wall

▶️ Answer/Explanation

Solution

Ans: D

Diffusion rate increases with greater concentration gradient (A), higher temperature (B), and larger surface area (C). A thicker cell wall (D) would slow diffusion as molecules have to travel further to reach the cell membrane.

Question 8

Topic: 4.1

Which row shows the chemical elements contained in fats?

▶️ Answer/Explanation

Solution

Ans: A

Fats are composed of carbon, hydrogen, and oxygen (CHO) without nitrogen. The correct combination is shown in row A (✓ for C, H, O and ✗ for N). Fats don’t contain nitrogen (unlike proteins), eliminating options B and C.

Question 9

Topic: 4.1

Glycogen is a large molecule made from smaller molecules.

Which smaller molecules is glycogen made from?

A. amino acids B. fatty acids C. glucose D. glycerol

▶️ Answer/Explanation

Solution

Ans: C

Glycogen is a carbohydrate polymer made of glucose monomers. Amino acids (A) make proteins, fatty acids (B) and glycerol (D) make lipids. Only glucose (C) is the correct building block for glycogen.

Question 10

Topic: 5.1

The diagrams represent an enzyme and its substrate.

Which part of the enzyme molecule is the active site for this substrate?

▶️ Answer/Explanation

Solution

Ans: C

The active site is the region where the substrate binds to the enzyme. In the diagram, part C shows the indentation where the substrate fits, following the lock-and-key model. Other parts are either too distant or don’t match the substrate’s shape.

Question 11

Topic: 6.1

What is a use of the carbohydrates made by photosynthesis?

A. to produce cellulose for energy stores B. to produce starch to build cell walls C. to produce starch for transport in the phloem D. to produce sucrose for transport in the phloem

▶️ Answer/Explanation

Solution

Ans: D

Plants convert photosynthesis products into sucrose for transport in phloem (D). Cellulose is for cell walls (A incorrect), starch is for storage not cell walls (B incorrect), and starch isn’t transported in phloem (C incorrect).

Question 12

Topic: 6.1

The diagram shows an experiment investigating the effect of light intensity on an aquatic plant.

Photosynthesis occurred in both test-tube P and test-tube Q. Both test-tubes were kept at the same temperature. The number of bubbles produced in test-tube P was 12 bubbles per minute.

What is the most likely number of bubbles produced in one minute in test-tube Q?

A. 0 B. 3 C. 12 D. 48

▶️ Answer/Explanation

Solution

Ans: D

Since Q is closer to the light source (10cm vs 20cm), it receives 4× more light intensity (inverse square law). With 12 bubbles at 20cm, Q at 10cm should produce about 48 bubbles (12 × 4).

Question 13

Topic: 7.3

Which human teeth are used for biting and cutting food?

A. canines and molars B. incisors and canines C. molars and premolars D. premolars and incisors

▶️ Answer/Explanation

Solution

Ans: B

Incisors are specialized for cutting/biting (flat edges), while canines help tear food. Molars/premolars (A/C/D) are for grinding, not biting. Thus, the correct pair is B (incisors and canines).

Question 14

Topic: 7.2

The diagram shows part of the human digestive system.

Which organ produces hydrochloric acid?

▶️ Answer/Explanation

Solution

Ans: A

The stomach (A) produces hydrochloric acid to create an acidic environment for pepsin activation and pathogen killing. Other organs (B-D) don’t produce HCl – liver makes bile, pancreas makes enzymes, and intestine absorbs nutrients.

Question 15

Topic: 7.1

Which part of a balanced diet is missing if a person develops rickets?

A. carbohydrates B. iron C. vitamin C D. vitamin D

▶️ Answer/Explanation

Solution

Ans: D

Rickets is caused by vitamin D deficiency (D), which affects calcium absorption for bone development. While other nutrients (A-C) are important, they don’t cause rickets – vitamin C deficiency causes scurvy, iron causes anemia.

Question 16

Topic: 8.3

By which process is water vapour lost from a leaf?

A. active transport B. diffusion C. osmosis D. photosynthesis

▶️ Answer/Explanation

Solution

Ans: B

Water vapor is lost from leaves through diffusion, the passive movement of molecules from high to low concentration. This process, called transpiration, occurs when water vapor diffuses out through stomata. Active transport (A) requires energy, osmosis (C) involves water movement across membranes, and photosynthesis (D) produces water, not loses it.

Question 17

Topic: 8.1

The pathway taken by water through a plant is shown.

root hair cells → root cortex cells → Z → mesophyll cells

Which part of the pathway is Z?

A. palisade cells B. phloem C. stomata D. xylem

▶️ Answer/Explanation

Solution

Ans: D

Water moves upward through plants primarily via the xylem vessels. After being absorbed by root hairs and passing through cortex cells, water enters xylem (Z) which transports it to leaves where it reaches mesophyll cells. Phloem (B) transports sugars, while stomata (C) are for gas exchange.

Question 18

Topic: 9.1

Which statement about the human circulatory system is correct?

A. a system of blood vessels with the arteries returning blood to the heart B. a system of blood vessels with a pump and valves to ensure one-way flow of blood C. blood flows away from the heart into the vena cava D. blood flows into the lungs from the pulmonary vein

▶️ Answer/Explanation

Solution

Ans: B

The circulatory system has blood vessels, the heart as a pump, and valves in veins/heart to maintain one-way flow. Arteries carry blood away from heart (A is wrong), vena cava returns blood to heart (C is reversed), and pulmonary vein brings oxygenated blood from lungs (D is backward). Thus, B is correct.

Question 19

Topic: 9.3

What are features of arteries?

1 narrow lumen
2 thick muscular wall
3 walls made of a single layer of cells
4 wide lumen

A. 1 and 2 B. 1 and 3 C. 2 and 4 D. 3 and 4

▶️ Answer/Explanation

Solution

Ans: A

Arteries have a narrow lumen (1) and thick muscular walls (2) to withstand high blood pressure. Capillaries have single-cell walls (3), and veins have wide lumens (4). Therefore, the correct combination is A (1 and 2), distinguishing arteries from other vessels.

Question 20

Topic: 10.1

What are disease-causing organisms?

A. antibodies B. pathogens C. phagocytes D. vaccines

▶️ Answer/Explanation

Solution

Ans: B

Pathogens are microorganisms (bacteria, viruses, etc.) that cause disease. Antibodies (A) fight pathogens, phagocytes (C) are white blood cells that engulf pathogens, and vaccines (D) prevent diseases. Thus, the correct term for disease-causing organisms is B (pathogens).

Question 21

Topic: 11.1

Which row shows the composition of expired air from a healthy person?

▶️ Answer/Explanation

Solution

Ans: D

Expired air contains about 4% carbon dioxide (higher than inhaled air), 16% oxygen (lower than inhaled air), and is saturated with water vapor. Option D correctly shows these values, while others have incorrect percentages or water vapor conditions.

Question 22

Topic: 11.1

What is the path of carbon dioxide as it leaves the lungs?

A. alveolus → bronchiole → bronchus → trachea B. alveolus → bronchus → bronchiole → trachea C. trachea → bronchiole → bronchus → alveolus D. trachea → bronchus → bronchiole → alveolus

▶️ Answer/Explanation

Solution

Ans: A

Carbon dioxide follows this path when exhaled: starts in alveoli (gas exchange), moves to bronchioles (smaller tubes), then bronchi (larger tubes), and finally trachea (windpipe) before exiting. Option A correctly shows this sequence from smallest to largest airways.

Question 23

Topic: 12.3

Which statement about anaerobic respiration is correct?

A. Anaerobic respiration requires oxygen and releases less energy per glucose molecule than aerobic respiration. B. Anaerobic respiration requires oxygen and releases more energy per glucose molecule than aerobic respiration. C. Anaerobic respiration does not require oxygen and releases less energy per glucose molecule than aerobic respiration. D. Anaerobic respiration does not require oxygen and releases more energy per glucose molecule than aerobic respiration.

▶️ Answer/Explanation

Solution

Ans: C

Anaerobic respiration occurs without oxygen (ruling out A/B) and produces less ATP (energy) per glucose than aerobic respiration (ruling out D). It’s an emergency process used when oxygen is scarce, making C the correct statement.

Question 24

Topic: 16.4

What is described as a ball of cells that implants into the lining of the uterus?

A. acrosome B. embryo C. fetus D. zygote

▶️ Answer/Explanation

Solution

Ans: B

The embryo is the early developmental stage (ball of cells) that implants in the uterus. A zygote (D) is a single cell, acrosome (A) is part of sperm, and fetus (C) develops later. The embryo forms after zygote division but before fetal stage.

Question 25

Topic: 13.1

The diagram shows parts of the body involved in excretion in humans.

What are the labelled parts?

▶️ Answer/Explanation

Solution

Ans: B

The correct sequence is: kidneys (W) produce urine → ureters (X) transport urine → bladder (Y) stores urine → urethra (Z) releases urine. Option B matches this order, while others mix up the structures’ functions.

Question 26

Topic: 14.1

The diagram shows a reflex action when a person touches a hot object and pulls their hand away.

Which letter correctly identifies a structure?

A. E is called the effector. B. F is called the motor neurone. C. G is called the motor neurone. D. H is called the receptor.

▶️ Answer/Explanation

Solution

Ans: C

In a reflex arc, the motor neurone carries impulses from the relay neurone to the effector (muscle). Here, G is correctly identified as the motor neurone. E is the receptor (not effector), F is the sensory neurone, and H is the effector (not receptor).

Question 27

Topic: 14.2

The diagram shows a section through a human eye.

Which structure changes shape in response to adrenaline?

▶️ Answer/Explanation

Solution

Ans: C

The pupil (structure C) changes size in response to adrenaline as part of the ‘fight or flight’ response. Adrenaline causes the radial muscles of the iris to contract, dilating the pupil to allow more light in for improved vision during stress.

Question 28

Topic: 19.4

What is an example of a population?

A. all the animals and plants living in a lake B. all the different herbivores in a forest C. all the mahogany trees growing in a forest D. all the species of animals in Africa

▶️ Answer/Explanation

Solution

Ans: C

A population refers to all members of the same species in a particular area. Only option C (mahogany trees) describes a single species group. The other options describe communities (A/B) or multiple species across a large area (D).

Question 29

Topic: 15.1

Which statement about antibiotics is correct?

A. Antibiotics are drugs. B. Antibiotics are produced by white blood cells. C. Antibiotics can become resistant to bacteria. D. Antibiotics kill viruses.

▶️ Answer/Explanation

Solution

Ans: A

Antibiotics are indeed drugs used to treat bacterial infections. They’re produced by fungi/bacteria (not white blood cells), bacteria become resistant to them (not vice versa), and they don’t work on viruses. Thus, only statement A is correct.

Question 30

Topic: 17.4

A pea plant with the genotype YY is crossed with a pea plant with the genotype yy.

What are the possible genotypes of the offspring?

A. YY and yy B. all Yy C. Yy and yy D. all YY

▶️ Answer/Explanation

Solution

Ans: B

When homozygous dominant (YY) crosses with homozygous recessive (yy), all offspring will be heterozygous (Yy). This follows Mendel’s law of segregation where each parent contributes one allele, resulting in uniform hybrid offspring.

Question 31

Topic: 12.2

Which graph shows the effect of temperature on the rate of respiration in yeast?

▶️ Answer/Explanation

Solution

Ans: A

Respiration in yeast increases with temperature up to an optimum point (around 37°C for most enzymes), then decreases as enzymes denature. This creates a bell-shaped curve, which matches graph A. The other graphs don’t show this characteristic pattern.

Question 32

Topic: 16.1

What is the correct description of asexual reproduction?

A. Genetically different offspring are produced from one parent. B. Genetically different offspring are produced from two parents. C. Genetically identical offspring are produced from one parent. D. Genetically identical offspring are produced from two parents.

▶️ Answer/Explanation

Solution

Ans: C

Asexual reproduction involves one parent producing genetically identical offspring through mitosis. This eliminates options involving two parents (B/D) or genetic variation (A). The key characteristics are single parent and identical offspring.

Question 33

Topic: 16.4

The diagram shows a human female’s reproductive organs.

Where does fertilisation usually occur?

▶️ Answer/Explanation

Solution

Ans: A

Fertilisation typically occurs in the oviduct (fallopian tube), where sperm meets egg. The ovary (B) releases eggs, the uterus (C) is for implantation, and the vagina (D) is the birth canal. The oviduct is the only site where fertilisation can occur.

Question 34

Topic: 17.4

The diagram shows part of a genetic diagram for the inheritance of sex in humans. The sex chromosomes in two gametes are shown.

What are the sex chromosomes in gametes 1 and 2?

▶️ Answer/Explanation

Solution

Ans: D

In humans, males are XY and produce either X or Y sperm (gamete 1), while females are XX and produce only X eggs (gamete 2). The father must contribute Y to make a male offspring, so gamete 1 is Y and gamete 2 is X, making option D correct.

Question 35

Topic: 18.1

Tusks are modified teeth.

In one part of the world, most elephants used to be born with tusks. Over the last 50 years, more female elephants have been born without tusks. These elephants are giving birth to offspring that also do not have tusks.

Which types of variation can be illustrated by this example?

▶️ Answer/Explanation

Solution

Ans: B

Tusk presence is a clear-cut trait (discontinuous variation) that’s inherited (genetic). It’s not continuous (no range of tusk sizes) and can’t be environmental since it’s passed to offspring. The scenario describes natural selection acting on this genetic variation.

Question 36

Topic: 19.2

The diagrams show pyramids of numbers and biomass.

Which pyramids could be pyramids of biomass?

A. 1 and 2 B. 1 and 4 C. 2 and 3 D. 3 and 4

▶️ Answer/Explanation

Solution

Ans: C

Pyramids of biomass are always upright (narrow at top) as energy decreases at each trophic level. Pyramids of numbers can be inverted (e.g., one tree supporting many insects). Therefore, the correct answer is C (2 and 3) as these represent typical biomass pyramids.

Question 37

Topic: 19.1

Which process transfers energy between the first and second trophic levels of a food chain?

A. egestion B. ingestion C. photosynthesis D. respiration

▶️ Answer/Explanation

Solution

Ans: B

Energy transfer between trophic levels occurs when organisms consume (ingest) other organisms. Photosynthesis (C) captures energy, respiration (D) releases it, and egestion (A) removes undigested matter. Thus, B (ingestion) is correct.

Question 38

Topic: 19.3

The diagram shows part of the carbon cycle.

Which arrow represents respiration?

▶️ Answer/Explanation

Solution

Ans: B

Respiration in green plants releases carbon dioxide back into the atmosphere. While animals (C) also respire, the question focuses on the diagram’s context where plants are the primary source. Thus, B (green plants) is the correct choice.

Question 39

Topic: 21.2

Why are bacteria useful in biotechnology and genetic modification?

A. They can manufacture complex molecules. B. They reproduce slowly. C. They have a nucleus. D. They are the same as plant cells.

▶️ Answer/Explanation

Solution

Ans: A

Bacteria are used in biotechnology because they can produce complex molecules (e.g., insulin) when genetically modified. They lack nuclei (C), reproduce quickly (B), and differ from plant cells (D). Hence, A is the correct answer.

Question 40

Topic: 21.3

What is a reason for inserting genes into bacterial cells?

A. to confer resistance to herbicides B. to confer resistance to insect pests C. to improve their nutritional qualities D. to produce human proteins

▶️ Answer/Explanation

Solution

Ans: D

Bacteria are commonly genetically modified to produce human proteins (e.g., insulin or growth hormones). Options A-C describe plant modifications. Therefore, D (to produce human proteins) is the primary reason for bacterial gene insertion.

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