Topic – 1.1
Which organisms carry out respiration, growth, movement and excretion?
A) all animals and all plants
B) animals only
C) arthropods and flowering plants only
D) plants only
▶️ Answer/Explanation
Ans: A
All living organisms, including both animals and plants, carry out these basic life processes. Plants respire (cellular respiration), grow, show movement (tropisms), and excrete waste products. Therefore, the correct answer is A (all animals and all plants).
Topic – 1.2
The chimpanzee belongs to the species Pan troglodytes.
What is the genus of this species?
A) chimpanzee
B) Pan
C) Pan troglodytes
D) troglodytes
▶️ Answer/Explanation
Ans: B
In binomial nomenclature, the first part of the scientific name (Pan) represents the genus, while the second part (troglodytes) is the species. Therefore, the genus is B (Pan).
Topic – 1.3
The diagram shows a tree leaf.
Use the key to identify the tree species to which the leaf belongs.
▶️ Answer/Explanation
Ans: D
Following the key: The leaf is compound (with many leaflets), which leads to the second option. Then, the leaf edge is jagged, which matches D (Sorbus aucuparia). The other options either have simple leaves or different edge characteristics.
Topic – 2.1
What is the function of mitochondria in cells?
A) to absorb light energy
B) to produce glucose
C) to release energy
D) to transport oxygen
▶️ Answer/Explanation
Ans: C
Mitochondria are known as the “powerhouses” of the cell because they release energy (C) through cellular respiration. Chloroplasts absorb light energy (A), glucose is produced in photosynthesis (B), and oxygen is transported by red blood cells (D).
Topic – 2.1
Which row shows a function of the cell membrane and a function of the cell wall in a palisade cell?
| cell membrane | cell wall | |
|---|---|---|
| A | active transport | active transport |
| B | active transport | support |
| C | support | active transport |
| D | support | support |
▶️ Answer/Explanation
Ans: B
The cell membrane controls what enters/exits the cell (including active transport), while the cell wall provides structural support. Therefore, the correct combination is B (active transport for membrane, support for wall).
Topic – 2.2
A specimen is viewed under a microscope with a ×10 magnification. The specimen image measures 30 mm.
What is the actual size of the specimen?
A) 3 μm
B) 30 μm
C) 300 μm
D) 3000 μm
▶️ Answer/Explanation
Ans: D
Actual size = Image size / Magnification = 30 mm / 10 = 3 mm. Convert mm to μm (1 mm = 1000 μm), so 3 mm = 3000 μm. Therefore, the correct answer is D (3000 μm).
Topic – 3.2
The diagram shows the water potential of three plant cells. The more negative the value, the higher the solute concentration.
What is the immediate movement of water that will occur between the three cells?
A) from P to Q, and from R to P and Q
B) from Q to P and R only
C) from Q to P and R, and from P to R
D) from R to Q only
▶️ Answer/Explanation
Ans: A
Water moves from higher (less negative) to lower (more negative) water potential. R (-340 kPa) has highest water potential, so water moves from R to both P (-360 kPa) and Q (-400 kPa). P has higher potential than Q, so water also moves from P to Q. Therefore, correct answer is A.
Topic – 17.1
Which base in a DNA molecule always pairs with a G base?
A) A
B) G
C) C
D) T
▶️ Answer/Explanation
Ans: C
In DNA base pairing, Guanine (G) always pairs with Cytosine (C) through three hydrogen bonds, while Adenine (A) pairs with Thymine (T) with two hydrogen bonds. Therefore, the correct answer is C (C).
Topic – 5.1
The diagram shows the steps in an enzyme-controlled reaction.
What describes the part labelled X?
A) active site
B) enzyme–substrate complex
C) product
D) substrate
▶️ Answer/Explanation
Ans: B
X represents the temporary structure formed when the enzyme binds to its substrate, called the enzyme-substrate complex. This occurs before the reaction takes place and products are formed. Therefore, the correct answer is B.
Topic – 5.1
The graph shows the effect of temperature on the time taken for the complete digestion of starch.
At which temperature is the rate of digestion of starch the greatest?
A) 10 °C
B) 30 °C
C) 40 °C
D) 50 °C
▶️ Answer/Explanation
Ans: C
The greatest rate of digestion occurs at the temperature where the time taken is shortest. From the graph (though not shown here), this occurs at 40°C, which is typically the optimal temperature for many enzymes. Higher temperatures may denature the enzyme.
Topic – 6.1
Which substance is needed to make chlorophyll and which part of the plant absorbs the substance?
| substance | part of the plant where the substance is absorbed | |
|---|---|---|
| A | calcium | root hairs |
| B | calcium | stomata |
| C | magnesium | root hairs |
| D | magnesium | stomata |
▶️ Answer/Explanation
Ans: C
Chlorophyll contains magnesium at its center, making it essential for photosynthesis. Plants absorb magnesium ions through their root hairs via active transport. While calcium is important for plant growth, it’s not part of chlorophyll structure. Stomata are for gas exchange, not mineral absorption.
Topic – 6.2
The diagram shows a type of plant cell.
In which tissue is this cell found?
A) leaf epidermis
B) palisade mesophyll
C) root epidermis
D) xylem
▶️ Answer/Explanation
Ans: B
The presence of chloroplasts indicates this is a photosynthetic cell. Palisade mesophyll cells (B) are packed with chloroplasts for maximum light absorption. Epidermal cells (A,C) are protective and lack chloroplasts, while xylem cells (D) are dead water-conducting cells without organelles.
Topic – 7.1
Which components of a balanced diet are needed to make haemoglobin and to prevent scurvy and rickets?
A) carbohydrates and mineral ions
B) carbohydrates and proteins
C) mineral ions and vitamins
D) vitamins and fibre
▶️ Answer/Explanation
Ans: C
Iron (a mineral ion) is needed for haemoglobin production. Vitamin C prevents scurvy, while vitamin D prevents rickets. While proteins contain amino acids for haemoglobin synthesis, the specific question asks about dietary components needed directly, making mineral ions and vitamins (C) the best answer.
Topic – 7.2
Which group of organs belongs to the same organ system?
A) diaphragm, oesophagus, trachea
B) heart, liver, lungs
C) heart, stomach, trachea
D) oesophagus, intestine, stomach
▶️ Answer/Explanation
Ans: D
The oesophagus, intestine, and stomach (D) all belong to the digestive system. Option A mixes respiratory (trachea) with digestive (oesophagus), B combines circulatory (heart), digestive (liver), and respiratory (lungs), while C mixes circulatory (heart), digestive (stomach), and respiratory (trachea).
Topic – 7.5
The diagram shows a villus.
Which parts transport glucose and fatty acids away from the villus?
| glucose | fatty acids | |
|---|---|---|
| A | 3 | 1 |
| B | 3 | 2 |
| C | 4 | 3 |
| D | 4 | 4 |
▶️ Answer/Explanation
Ans: C
In villi, glucose is absorbed into blood capillaries (typically labeled 4), while fatty acids are absorbed into lacteals (lymph vessels, typically labeled 3). This separation occurs because glucose is water-soluble and enters blood directly, while fatty acids are packaged into chylomicrons for lymphatic transport.
Topic – 8.3
Which conditions lead to the lowest rate of transpiration in a plant?
A) cool and high humidity
B) cool and windy
C) warm and low humidity
D) warm and windy
▶️ Answer/Explanation
Ans: A
Transpiration is lowest in cool temperatures (reduces water molecule energy) and high humidity (reduces water potential gradient between leaf and air). Wind increases transpiration (D), while warm temperatures (C) and low humidity both increase water loss.
Topic – 8.4
The table shows the transport tissues of plants and some substances that may or may not travel through these tissues.
Which row is correct for translocation?
| plant tissue | substance transported | |
|---|---|---|
| A | phloem | maltose |
| B | phloem | sucrose |
| C | xylem | amino acids |
| D | xylem | water |
▶️ Answer/Explanation
Ans: B
Translocation occurs in phloem tissue (not xylem), transporting sucrose (not maltose). While xylem transports water (D is correct for xylem function but not translocation), only option B correctly describes phloem’s role in translocation of sucrose.
Topic – 9.1
The diagram shows the circulatory system of a fish.
What is the structure labelled X?
A) aorta
B) gills
C) heart
D) vena cava
▶️ Answer/Explanation
Ans: B
In fish circulation, blood becomes oxygenated at the gills (B). The heart (C) pumps deoxygenated blood, while aorta (A) and vena cava (D) are mammalian structures. X shows where blood changes from deoxygenated to oxygenated, indicating gills.
Topic – 9.2
Which factors increase the risk of developing coronary heart disease?
- increased age
- regular exercise
- smoking
- stress
A) 1, 2 and 3
B) 1, 2 and 4
C) 1, 3 and 4
D) 2, 3 and 4
▶️ Answer/Explanation
Ans: C
Coronary heart disease risk increases with age (1), smoking (3 damages blood vessels), and stress (4 raises blood pressure). Regular exercise (2) actually reduces risk by improving cardiovascular health, so options including 2 are incorrect.
Topic – 10.1
Which features of the human body protect against pathogens in food?
| red blood cells | stomach acid | white blood cells | |
|---|---|---|---|
| A | yes | yes | no |
| B | yes | no | no |
| C | no | yes | yes |
| D | no | no | yes |
▶️ Answer/Explanation
Ans: C
Stomach acid kills pathogens in food, and white blood cells provide immune defense. Red blood cells (transport oxygen) don’t fight pathogens. Only option C correctly identifies both stomach acid (chemical barrier) and white blood cells (immune defense) as protective.
Topic – 11.1
What causes air to enter the lungs?
| external intercostal muscles | volume of thorax | air pressure in thorax | |
|---|---|---|---|
| A | contract | decreases | decreases |
| B | relax | decreases | increases |
| C | contract | increases | decreases |
| D | relax | increases | increases |
▶️ Answer/Explanation
Ans: C
When breathing in, external intercostal muscles contract, raising the ribs and increasing thorax volume. This creates lower pressure inside the thorax compared to outside, causing air to rush into the lungs.
Topic – 12.2
The symbol equation for aerobic respiration is shown.
\[ \text{C}_6\text{H}_x\text{O}_y + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} \]
Which numbers represent the letters shown in the equation as x, y and z?
| x | y | z | |
|---|---|---|---|
| A | 2 | 12 | 6 |
| B | 6 | 2 | 12 |
| C | 6 | 12 | 2 |
| D | 12 | 6 | 2 |
▶️ Answer/Explanation
Ans: D
The correct formula for glucose is C6H12O6, so x=12, y=6. The equation is already balanced with z=2 (6H2O). Therefore, the correct combination is D.
Topic – 12.3
A student investigates the rate of anaerobic respiration in yeast.
The total volume of carbon dioxide produced is measured every 10 minutes for 40 minutes. The table shows the results.
| time/minutes | total volume of carbon dioxide produced/cm3 |
|---|---|
| 0 | 6 |
| 10 | 30 |
| 20 | 37 |
| 30 | 40 |
| 40 | 41 |
Between which times is the rate of anaerobic respiration fastest?
A) 0-10 minutes
B) 10-20 minutes
C) 20-30 minutes
D) 30-40 minutes
▶️ Answer/Explanation
Ans: A
The fastest rate occurs between 0-10 minutes where CO2 production increases by 24 cm3 (30-6). Later intervals show smaller increases (7, 3, and 1 cm3 respectively), indicating slowing respiration as substrates are used up.
Topic – 13.1
Which part of an amino acid is removed during deamination?
A) the carbon-containing part
B) the nitrogen-containing part
C) the oxygen-containing part
D) the iron-containing part
▶️ Answer/Explanation
Ans: B
Deamination removes the nitrogen-containing amino group (-NH2) from amino acids, converting it to ammonia which is then processed into urea. The carbon skeleton remains for energy production.
Topic – 13.1
Which process happens in a glomerulus in the kidney?
A) assimilation
B) deamination
C) filtration
D) reabsorption
▶️ Answer/Explanation
Ans: C
The glomerulus performs ultrafiltration, where small molecules like water, glucose, and urea are forced out of blood into Bowman’s capsule under pressure. Larger molecules like proteins remain in blood.
Topic – 14.1
The diagram shows a synapse in a reflex arc.
What are the identities of the two neurones and in which direction does the neurotransmitter pass?
| neurone P | neurone Q | direction of passage of the neurotransmitter | |
|---|---|---|---|
| A | motor | relay | P → Q |
| B | motor | sensory | P → Q |
| C | relay | motor | Q → P |
| D | relay | sensory | Q → P |
▶️ Answer/Explanation
Ans: D
In a reflex arc, the neurotransmitter passes from the relay neurone (P) to the sensory neurone (Q). The direction is always from the presynaptic neurone to the postsynaptic neurone, which in this case is Q → P. Therefore, the correct answer is D.
Topic – 14.2
Which responses occur in the iris of the eye when a person walks from a brightly lit area to a dimly lit area?
| circular muscles | radial muscles | |
|---|---|---|
| A | contract | contract |
| B | contract | relax |
| C | relax | contract |
| D | relax | relax |
▶️ Answer/Explanation
Ans: C
In dim light, the circular muscles of the iris relax to allow the pupil to dilate, while the radial muscles contract to help widen the pupil. This allows more light to enter the eye, improving vision in low light conditions.
Topic – 14.3
Which statements about hormones are correct?
- Adrenaline decreases pupil diameter.
- Adrenaline increases pupil diameter.
- Insulin decreases blood glucose concentration.
- Insulin increases blood glucose concentration.
A) 1 and 3
B) 1 and 4
C) 2 and 3
D) 2 and 4
▶️ Answer/Explanation
Ans: C
Adrenaline increases pupil diameter (statement 2 is correct) to allow more light into the eye during ‘fight or flight’ responses. Insulin decreases blood glucose concentration (statement 3 is correct) by promoting glucose uptake by cells. Therefore, the correct combination is C (2 and 3).
Topic – 18.3
Bacteria such as MRSA are resistant to antibiotics.
These processes can occur in bacteria.
- artificial selection
- genetic variation
- mutation
- natural selection
Which processes lead to the development of antibiotic resistance?
A) 1, 2, 3 and 4
B) 1, 2 and 3 only
C) 2, 3 and 4 only
D) 2 and 4 only
▶️ Answer/Explanation
Ans: C
Antibiotic resistance develops through natural processes: genetic variation (2) provides diversity, mutations (3) can create resistance, and natural selection (4) favors resistant bacteria when antibiotics are present. Artificial selection (1) is human-directed and not involved in natural resistance development.
Topic – 16.3
A farmer grows hot pepper plants and sweet pepper plants in different fields on his farm.
Each year, the farmer saves seeds from the pepper plants to grow the next crop of peppers.
One year, the farmer notices that some of the seeds from the sweet pepper plants have grown into plants which produce hot and sweet peppers.
What is the most likely explanation?
A) Self-pollination has occurred and pollen has been transferred from the anther of a hot pepper plant to the stigma of a sweet pepper plant.
B) Cross-pollination has occurred and pollen has been transferred from the stigma of a hot pepper plant to the anther of a sweet pepper plant.
C) Self-pollination has occurred and pollen has been transferred from the stigma of a hot pepper plant to the anther of a sweet pepper plant.
D) Cross-pollination has occurred and pollen has been transferred from the anther of a hot pepper plant to the stigma of a sweet pepper plant.
▶️ Answer/Explanation
Ans: D
The appearance of both hot and sweet peppers suggests cross-pollination between the two varieties. Pollen moves from anther to stigma (not stigma to anther), and cross-pollination occurs between different plants. Therefore, D is correct as it describes pollen transfer from a hot pepper plant’s anther to a sweet pepper plant’s stigma.
Topic – 17.1
Why do different cells in a human body produce different proteins?
A) Alleles can be dominant or recessive.
B) Only particular genes are expressed.
C) Cells have different genes.
D) The sequence of bases in the DNA varies between different cells.
▶️ Answer/Explanation
Ans: B
Different cells produce different proteins because of gene expression – only specific genes are activated in each cell type. While all cells contain the same DNA (C is wrong), selective gene expression (B) leads to specialized protein production. This explains why muscle cells make different proteins than nerve cells, despite having identical DNA.
Topic – 17.2
Which graph shows the mean mass of DNA per cell before, during and after mitosis?
A) 
B) 
C) 
D) 
▶️ Answer/Explanation
Ans: B
The correct graph (B) shows DNA mass doubling during S-phase (before mitosis), remaining at this doubled level through mitosis, then halving when the cell divides. This matches how DNA replicates once per cell cycle, with each daughter cell receiving one complete copy.
Topic – 17.1
Which statement about gene mutations is correct?
A) A mutation is a change in the amino acid sequence of DNA.
B) Mutations are a source of genetic variation.
C) Mutations are caused by random mating.
D) Mutations happen during random fertilisation.
▶️ Answer/Explanation
Ans: B
Mutations create new alleles (B), introducing genetic variation. A is wrong because mutations change DNA bases, not amino acids directly. C and D are incorrect as mutations occur due to DNA replication errors or mutagens, not mating or fertilization processes.
Topic – 19.1
The diagram shows the amount of energy in kJ m-2 yr-1 at each trophic level of a food chain.
Approximately how much energy is lost between the producers and the secondary consumers?
A) 0.2%
B) 2.0%
C) 84%
D) 98%
▶️ Answer/Explanation
Ans: D
Energy loss is calculated as: (88,000-2,000)/88,000 × 100 = 97.7% ≈ 98%. This massive loss occurs because energy is wasted as heat (respiration), undigested materials, and movement at each trophic level, following the 10% rule in ecosystems.
Topic – 19.3
Which process in the nitrogen cycle removes nitrogen gas from the atmosphere?
A) decomposition
B) denitrification
C) nitrification
D) nitrogen fixation
▶️ Answer/Explanation
Ans: D
Only nitrogen fixation (D) converts atmospheric N2 into usable forms like ammonia. Decomposition (A) breaks down organic matter, nitrification (C) converts ammonia to nitrates, while denitrification (B) actually returns nitrogen to the atmosphere.
Topic – 19.4
What is a population?
A) a group of different organisms living in different areas at the same time
B) a group of organisms of different species living in the same area
C) a group of organisms of one species living in the same area at different times
D) a group of organisms of one species living in the same area at the same time
▶️ Answer/Explanation
Ans: D
A population specifically refers to members of the same species living together in the same area at the same time. Options A and B describe communities (multiple species), while C describes a population across different time periods. Only D meets all criteria.
Topic – 20.3
A farmer has a small pond on their farm land.
One year, most of the organisms in the pond die.
The next year, the farmer decreases their use of nitrate fertilisers and fewer organisms in the pond die.
Which statement explains why this will help increase the number of organisms living in the pond?
A) There is a decrease in dissolved oxygen due to an increase in decomposition.
B) There is a decrease in dissolved oxygen due to an increase in photosynthesis.
C) There is an increase in dissolved oxygen due to a decrease in decomposition.
D) There is an increase in dissolved oxygen due to a decrease in photosynthesis.
▶️ Answer/Explanation
Ans: C
Excess nitrates cause algal blooms that die and decompose, consuming oxygen (eutrophication). Reducing nitrates decreases decomposition, leaving more oxygen for aquatic life. Photosynthesis (B/D) would increase oxygen, but the key factor is reduced decomposition from fewer algae.
Topic – 20.4
The graph shows how the population of a species of bird has increased following a conservation programme.
What is the percentage increase in the number of breeding pairs of birds from 1996 to 2002, to the nearest whole number?
A) 35%
B) 74%
C) 170%
D) 283%
▶️ Answer/Explanation
Ans: D
Assuming the graph shows ~100 pairs in 1996 and ~383 pairs in 2002: Percentage increase = [(383-100)/100] × 100 = 283%. This matches option D. The exact values aren’t visible, but the sharp upward trend suggests a large percentage increase.
Topic – 21.3
The diagram shows a bacterial cell that is used in genetic modification.
Which labelled structure makes the bacterium useful for genetic modification?
▶️ Answer/Explanation
Ans: C
Plasmids (C) are small, circular DNA molecules in bacteria that can be easily modified to carry foreign genes. They replicate independently and are key tools in genetic engineering. The other structures (cell wall, flagellum, ribosome) don’t directly facilitate genetic modification.
Topic – 21.2
The diagram shows some apparatus that was used to produce lactose-free milk.
The alginate beads do not react with any of the substances. X is an enzyme that catalyses a reaction involving one of the substances found in milk.
What are X and Y?
| X | Y | |
|---|---|---|
| A | amylase | glucose |
| B | amylase | starch |
| C | lactase | glucose |
| D | lactase | starch |
▶️ Answer/Explanation
Ans: C
To make lactose-free milk, lactase (X) breaks down lactose into glucose and galactose (Y would include glucose). Amylase (A/B) breaks down starch, which isn’t relevant here. The correct pair is C: lactase and glucose, as lactose is milk’s sugar.