IGCSE Biology 0610/13 May/June 2025 Past Paper with Answers

Question 1

The Venus flytrap is a plant that feeds on insects. When an insect lands on a specially adapted leaf, the leaf folds very quickly to trap the insect, and the leaves then produce enzymes which digest it. Which three characteristics of living organisms are involved in this?

1. movement, sensitivity and nutrition
2. excretion, growth and nutrition
3. movement, excretion and nutrition
4. movement, sensitivity and growth

Question 2

A rat has the scientific name Rattus rattus, written using the binomial system. What do the two parts of this scientific name refer to?

1. genus and species
2. kingdom and genus
3. kingdom and species
4. species and group

Question 3

Crustaceans are a group of arthropods that typically have a hard exoskeleton, several pairs of jointed legs and two pairs of antennae (feelers). Four small animals are compared. Which animal is a crustacean?

1. a crab, which has a hard shell, several pairs of jointed legs and two pairs of feelers
2. a spider, which has a body in two parts and eight legs
3. a beetle, which has a body in three parts, six legs and one pair of feelers
4. a centipede, which has a long body of many segments, each with a pair of legs

Question 4 · Answer A

Step 1: Animal cells contain cytoplasm and a nucleus, which they share with plant cells. Step 2: Animal cells do not contain chloroplasts, because they do not photosynthesise. Step 3: So an animal cell has cytoplasm and a nucleus but no chloroplasts; the other combinations either add chloroplasts or remove the cytoplasm or nucleus, which is wrong.

Question 5 · Answer A

Step 1: Magnification = image (drawing) length divided by actual length. Step 2: This gives 30 mm ÷ 200 mm = 0.15. Step 3: The drawing is smaller than the real animal, so the magnification is less than 1; 6.67 divides the wrong way round, 15 misplaces the decimal, and 6000 multiplies instead of divides.

Question 6 · Answer A

Step 1: In the concentrated sugar solution the water outside the cells is less concentrated in water than inside, so water leaves the potato cells by osmosis and the mass decreases. Step 2: In distilled water there is more water outside than inside the cells, so water enters by osmosis and the mass increases. Step 3: So the mass goes down in the sugar solution and up in the distilled water.

Question 7 · Answer A

Step 1: Active transport moves particles against their concentration gradient, that is from a lower to a higher concentration, using energy from respiration. Step 2: It takes place across the cell membrane, and animal cells do not have a cell wall. Step 3: So the correct description is from a lower to a higher concentration across a cell membrane; moving from high to low is diffusion, and animal cells have no cell wall.

Question 8 · Answer A

Step 1: Reducing sugars are tested with Benedict’s solution, which turns from blue to brick red when heated with a reducing sugar. Step 2: Vitamin C is tested with DCPIP solution, which is decolourised by vitamin C. Step 3: So the correct pair is Benedict’s for reducing sugars and DCPIP for vitamin C; the biuret test is for protein and the ethanol emulsion test is for fats, so they are wrong.

Question 9 · Answer A

Step 1: An enzyme has an optimum pH at which its activity is highest, and activity falls on either side of this pH. Step 2: This gives a curve that rises to a peak at the optimum pH and then falls, a hump shape. Step 3: A flat, steadily rising or steadily falling line does not show an optimum, so those graphs are wrong.

Question 10 · Answer A

Step 1: As temperature rises too high, the enzyme’s shape is permanently changed (denatured) and it stops working, so the reaction rate falls to zero. Step 2: The enzyme is completely denatured at the high-temperature point where the rate has dropped back to zero. Step 3: The peak is the optimum (most active), the low-temperature point is just a slow rate, and the point still part way down means the enzyme is only partly denatured, so the rate is not yet zero.

Question 11 · Answer A

Step 1: Plant cell walls are made of cellulose, a carbohydrate built from many glucose units. Step 2: So cellulose is the carbohydrate used to build plant cell walls. Step 3: Glycogen is an animal energy store, starch is a plant energy store, and sucrose is a transport sugar, so none of these builds the cell wall.

Question 12 · Answer A

Step 1: The top of the leaf is covered by a waxy cuticle, which lies on top of the upper epidermis. Step 2: Below the epidermis is the palisade mesophyll, then the spongy mesophyll towards the lower surface. Step 3: So the order is cuticle, epidermis, palisade mesophyll, spongy mesophyll; putting epidermis above the cuticle or spongy above palisade is wrong.

Question 13 · Answer A

Step 1: Iron is needed to make haemoglobin in red blood cells. Step 2: Without enough iron, fewer red blood cells (with less haemoglobin) are made, causing anaemia. Step 3: Bleeding gums and poor wound healing are caused by lack of vitamin C, and weak bones and teeth by lack of calcium or vitamin D, so these are not the result of lacking iron.

Question 14 · Answer A

Step 1: Lipase is a fat-digesting enzyme made mainly by the pancreas, which releases it into the small intestine. Step 2: So lipase is made in the pancreas. Step 3: The stomach makes protease, the liver makes bile (not an enzyme), and the salivary glands make amylase, so none of these is the main source of lipase.

Question 15 · Answer A

Step 1: The stomach makes protease, which digests protein, so the stomach, protease and protein go together. Step 2: Amylase, made in the mouth and pancreas, digests starch, not protein. Step 3: So protease acting on protein in the stomach is the correct row; the others pair an enzyme with the wrong substrate or the wrong site.

Question 16 · Answer A

Step 1: Water is absorbed first by the root hair cells, then passes across the root cortex cells. Step 2: It then enters the xylem, which carries it up to the leaves. Step 3: In the leaf it passes into the mesophyll cells, so the order is root hair cells, root cortex cells, xylem, mesophyll cells.

Question 17 · Answer A

Step 1: A vessel carrying blood away from an organ towards the heart is a vein. Step 2: The vein that carries blood away from the kidney is the renal vein. Step 3: The renal artery carries blood into the kidney, while the pulmonary vessels connect the heart and lungs, not the kidney.

Question 18 · Answer A

Step 1: A curved bone of the chest wall is a rib (T), and the muscle in the gap between two ribs is an intercostal muscle (U). Step 2: The large dome-shaped sheet of muscle across the bottom of the chest is the diaphragm (V), and the tiny air sacs at the ends of the airways are the alveoli (W). Step 3: So T is a rib, U an intercostal muscle, V the diaphragm and W the alveoli; the other rows swap the rib with the intercostal muscle or the diaphragm with the alveoli.

Question 19 · Answer A

Step 1: Aerobic respiration releases energy from glucose using oxygen, and this takes place in the mitochondria. Step 2: So the mitochondrion is the site of aerobic respiration in plant cells. Step 3: The chloroplast carries out photosynthesis, the nucleus controls the cell, and ribosomes make proteins, so none of these is the site of aerobic respiration.

Question 20 · Answer A

Step 1: In human muscles, anaerobic respiration breaks down glucose without oxygen to form lactic acid. Step 2: So lactic acid is the product of anaerobic respiration in muscles. Step 3: Alcohol (and carbon dioxide) are products of anaerobic respiration in yeast, not human muscle, and glucose is the reactant, not a product.

Question 21 · Answer A

Step 1: The tube carrying urine from a kidney down to the bladder is a ureter, so X is a ureter. Step 2: The tube carrying urine from the bladder out of the body is the urethra, so Y is the urethra. Step 3: The renal artery and renal vein are blood vessels of the kidney, not the urine tubes, and X is the ureter (not the urethra), so the other options are wrong.

Question 22 · Answer A

Step 1: The iris is the coloured ring of muscle at the front of the eye that surrounds the pupil (the central opening) and controls how much light enters. Step 2: So the iris is the coloured ring around the central opening. Step 3: The transparent front layer is the cornea, the rounded clear structure behind it is the lens, and the light-sensitive back layer is the retina, so none of these is the iris.

Question 23 · Answer A

Step 1: Insulin is released by the pancreas when blood glucose is high and causes glucose to be taken up and stored, lowering the blood glucose concentration. Step 2: So insulin decreases blood glucose. Step 3: Adrenaline and glucagon raise blood glucose, and oestrogen is a sex hormone that does not control blood glucose, so they do not match.

Question 24 · Answer A

Step 1: Asexual reproduction involves only one parent and no gametes, so the offspring are produced from that single parent. Step 2: Because there is no mixing of genetic material, the offspring are genetically identical to the parent and to each other (clones). Step 3: So asexual reproduction gives genetically identical offspring from one parent; involving two parents or producing genetically different offspring describes sexual reproduction.

Question 25 · Answer A

Step 1: Germination needs water, oxygen and a suitable warm temperature. Step 2: Only the tube with moist cotton wool at 25 degrees Celsius with air present supplies all three, so its seeds germinate first. Step 3: The cold tube (0 degrees Celsius) lacks warmth, the dry tube lacks water, and the de-oxygenated tube under oil lacks oxygen, so seeds in those tubes do not germinate first.

Question 26 · Answer A

Step 1: Sperm are made in the testes, which contain the tubes where sperm are produced. Step 2: So sperm are produced in the testes. Step 3: The penis delivers sperm, the prostate gland adds fluid to make semen, and the scrotum is the sac that holds the testes, so none of these produces sperm.

Question 27 · Answer A

Step 1: In a 28-day cycle, ovulation (the release of an egg from the ovary) happens around the middle, on about day 14. Step 2: So the ovary releases an egg on day 14. Step 3: The uterus lining breaks down at the start of the cycle (around days 1 to 5), then builds up after that, so the other statements give the wrong day or the wrong event.

Question 28 · Answer A

Step 1: A gene can exist as different versions called alleles, and B and b are two different alleles of the same gene. Step 2: Having two different alleles of a gene is described as heterozygous, so Bb is heterozygous. Step 3: Homozygous means two identical alleles (such as BB or bb), and "two different genes of the same allele" is the wrong way round, so the other options are incorrect.

Question 29 · Answer A

Step 1: Inheritance is the passing on of genetic information from parents to their offspring. Step 2: So inheritance is the transmission of genetic information from one generation to the next. Step 3: The other statements describe particular individuals (not pure-breeding), a comparison of genotypes, or just dominant alleles, none of which is the meaning of inheritance.

Question 30 · Answer A

Step 1: Natural selection acts on the genetic variation that exists within a population, so that better-adapted individuals survive and reproduce. Step 2: So genetic variation within populations is a feature of natural selection. Step 3: Resources are usually limited (causing competition), offspring vary rather than being identical, and selection by humans is artificial selection, so the other options do not describe natural selection.

Question 31 · Answer A

Step 1: Energy enters most food chains when plants capture light energy from the Sun during photosynthesis. Step 2: So the Sun is the principal source of energy input to biological systems. Step 3: Carbon dioxide and minerals are raw materials, and glucose is made by plants using the Sun’s energy, so none of these is the original energy source.

Question 32 · Answer A

Step 1: A valid food chain must follow arrows that exist in the web, each organism being eaten by the next. Step 2: Grass is eaten by the grasshopper, the grasshopper by the frog, and the frog by the hawk, so grass → grasshopper → frog → hawk is a real chain. Step 3: The frog does not eat grass, the mouse does not eat the grasshopper, and the fox does not eat the owl, so the other chains break the links in the web.

Question 33 · Answer A

Step 1: Fossil fuels are the remains of organisms whose carbon was fixed by photosynthesis millions of years ago. Step 2: Burning (combustion) of these fossil fuels releases that stored carbon back into the air as carbon dioxide. Step 3: Respiration releases carbon dioxide from recently living organisms, not ancient fossil fuels, and photosynthesis removes carbon dioxide from the air, so the other options are wrong.

Question 34 · Answer A

Step 1: As a population grows, resources such as food and space eventually run short, which slows and then stops the increase. Step 2: This makes the curve level off and stay roughly constant at the top, so the limiting by resources is shown by the flat part at the top. Step 3: The slow start and the rising parts are phases where growth is still increasing, not where resources have limited it, so they are not correct.

Question 35 · Answer A

Step 1: Restricting the animals’ movement means they use less energy moving about, so more energy from their food goes into growth. Step 2: This increases the yield of animal product (such as meat), which is an advantage of method 1. Step 3: Increased pollution, more food eaten per animal, and a faster spread of disease are all disadvantages of intensive farming, not advantages.

Question 36 · Answer A

Step 1: An acidic environment has a pH below 7, so a species unable to live in acid must have a range that does not go below pH 7. Step 2: The species surviving only from about pH 7.0 to pH 9.5 never lives below pH 7, so it cannot live in an acidic environment. Step 3: The other three species each have ranges that extend below pH 7, so they can survive in at least some acidic conditions.

Question 37 · Answer A

Step 1: Biodiversity is maintained when the variety of species and their habitats is conserved. Step 2: Protecting habitats keeps the conditions that many species need, so it helps to maintain biodiversity. Step 3: Herbicides and insecticides kill plants and insects, and large-scale monocultures replace varied habitats with a single crop, so all of these reduce biodiversity.

Question 38 · Answer A

Step 1: Before the sewage (at W and X) the water is clean, so the oxygen concentration is high. Step 2: Just after the sewage enters (at Y), microorganisms break down the sewage and use up oxygen, so the oxygen concentration falls to a low value. Step 3: Further downstream (at Z) the sewage has been broken down and oxygen returns, so the concentration rises again, giving high-high-low-recovering across W, X, Y, Z.

Question 39 · Answer A

Step 1: Bacteria can be given a gene so that they make a useful complex molecule, such as a protein like insulin. Step 2: Being able to make complex molecules is what makes bacteria useful in genetic modification. Step 3: Having a cell membrane or a cell wall is a general feature of many cells, and bacteria actually reproduce quickly, not slowly, so these are not the reason they are useful.

Question 40 · Answer A

Step 1: The modification increases lycopene, a substance that may give health benefits when eaten. Step 2: Adding a beneficial nutrient improves the nutritional quality of the fruit, so that is the purpose. Step 3: The change does not involve pest resistance, herbicide resistance, or growing more fruit, so the other purposes do not match the information given.