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BGCSE Biology 0572 study materials
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BGCSE Biology 0572 practice questions

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Question 1Cells and Cell Processes

Which structure controls the movement of substances into and out of a cell?

  1. The cell membrane Correct answer.
  2. The cytoplasm
  3. The vacuole
  4. The nucleus

Explanation

The cell membrane is a thin partially permeable layer surrounding the cell, and it regulates which substances enter or leave. Other organelles lie inside the cell and do not form the outer boundary.

Question 2Cells and Cell Processes

Which organelle is the main site of aerobic respiration in a cell?

  1. The mitochondrion Correct answer.
  2. The lysosome
  3. The chloroplast
  4. The ribosome

Explanation

Mitochondria contain the enzymes for aerobic respiration, releasing energy from glucose using oxygen. Cells with high energy demands, such as muscle cells, contain many of them.

Question 3Cells and Cell Processes

A student views onion epidermis cells using a light microscope. Which feature would be visible?

  1. Golgi apparatus
  2. Cell wall Correct answer.
  3. Ribosomes
  4. Endoplasmic reticulum

Explanation

A light microscope can resolve structures larger than about half a micrometre, so the thick cellulose cell wall of a plant cell is clearly seen. Ribosomes and membrane systems are too small to resolve with light.

Question 4Cells and Cell Processes

Which process allows oxygen to move from the alveoli into the blood without using energy from the body?

  1. Diffusion Correct answer.
  2. Endocytosis
  3. Osmosis
  4. Active transport

Explanation

Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, and it needs no energy input. Oxygen is more concentrated in the alveoli than in the blood, so it diffuses across the thin alveolar wall.

Question 5Cells and Cell Processes

Which statement best describes the function of enzymes?

  1. They raise the activation energy of reactions.
  2. They are biological catalysts that speed up reactions. Correct answer.
  3. They provide energy directly to reactions.
  4. They are used up completely during each reaction.

Explanation

Enzymes are protein molecules that act as biological catalysts, increasing the rate of reactions without being consumed. They work by lowering the activation energy needed for the reaction.

Question 6Cells and Cell Processes

Which part of a plant cell is made mainly of cellulose and gives the cell a fixed shape?

  1. The cell wall Correct answer.
  2. The cell membrane
  3. The cytoplasm
  4. The nucleus

Explanation

The cell wall is a rigid layer of cellulose outside the cell membrane. It provides support and keeps the shape of plant cells fixed, even when the cell takes in water.

Question 7Cells and Cell Processes

Which of these is present in a bacterial cell but absent from a typical human cheek cell?

  1. A cell wall Correct answer.
  2. A cell membrane
  3. Ribosomes
  4. A cytoplasm

Explanation

Bacteria have a cell wall made of peptidoglycan outside the membrane, whereas animal cells have no cell wall. Both cell types contain a membrane, cytoplasm and ribosomes.

Question 8Cells and Cell Processes

In a solution of sugar and water, which substance is the solvent?

  1. The mixture
  2. The water Correct answer.
  3. The sugar
  4. The dissolved particles

Explanation

The solvent is the liquid that dissolves another substance, and here water dissolves the sugar. The sugar is the solute, and together they form a solution.

Question 9Cells and Cell Processes

A student places a plant cell in pure water. Which change is most likely to occur?

  1. The cell becomes turgid as water enters by osmosis. Correct answer.
  2. The cell shrinks as water leaves by osmosis.
  3. The cell bursts immediately because it has no wall.
  4. No water moves because the cell is isotonic with pure water.

Explanation

Pure water has a higher water potential than the cell sap, so water enters the cell by osmosis and pushes the membrane against the wall, making the cell turgid. The strong wall prevents bursting.

Question 10Cells and Cell Processes

Which statement explains why an enzyme stops working when heated to about 70 degrees Celsius?

  1. The reaction becomes endothermic at this temperature.
  2. The enzyme's active site changes shape as the protein is denatured. Correct answer.
  3. The enzyme is used up faster at higher temperatures.
  4. The substrate molecules become too small to bind.

Explanation

Enzymes are proteins, and high temperatures break the bonds holding their three-dimensional shape. The active site loses its complementary shape, so the substrate can no longer bind and the enzyme is denatured.

Question 11Cells and Cell Processes

Which feature of a root hair cell most increases the rate at which it absorbs water and mineral ions?

  1. A large central vacuole
  2. A long thin extension of the cell surface Correct answer.
  3. A thick waxy cuticle
  4. Many chloroplasts

Explanation

The long narrow extension greatly increases the surface area of the cell membrane in contact with soil water. A larger surface area allows faster absorption by osmosis and active transport.

Question 12Cells and Cell Processes

Which statement best describes the role of the nucleus in a eukaryotic cell?

  1. It breaks down worn-out organelles.
  2. It contains DNA and controls the activities of the cell. Correct answer.
  3. It synthesises lipids for the membrane.
  4. It packages proteins for secretion.

Explanation

The nucleus contains chromosomes made of DNA, which carry the instructions for making proteins. These instructions control metabolism, growth and division of the cell.

Question 13Cells and Cell Processes

A cell is observed to have a cell wall, a large permanent vacuole and no chloroplasts. Which type of cell is it most likely to be?

  1. A root hair cell from a plant Correct answer.
  2. A palisade mesophyll cell
  3. A human red blood cell
  4. A bacterium

Explanation

A cell wall and a large permanent vacuole indicate a plant cell, and the absence of chloroplasts fits a root cell that is underground and does not photosynthesise. Palisade cells would contain chloroplasts.

Question 14Cells and Cell Processes

Which pair of factors must be controlled to investigate how temperature affects the rate of an enzyme-catalysed reaction?

  1. The volume of the room and the mass of the enzyme bottle
  2. The shape of the beaker and the name of the enzyme
  3. The pH and the substrate concentration Correct answer.
  4. The colour of the test tube and the time of day

Explanation

In a fair test only the independent variable, temperature, should change. Factors such as pH and substrate concentration also affect enzyme activity, so they must be kept constant to make the comparison valid.

Question 15Cells and Cell Processes

Water moves into a potato strip placed in a dilute sugar solution. Which statement best explains this observation?

  1. The potato cells have a lower water potential than the surrounding solution. Correct answer.
  2. Sugar molecules move into the potato cells by osmosis.
  3. The sugar solution has a lower water potential than the potato cells.
  4. Water moves against its concentration gradient using energy.

Explanation

Osmosis moves water from a region of higher water potential to a region of lower water potential. Water enters the potato only if the cell contents have the lower water potential, so the external solution is more dilute.

Question 16Cells and Cell Processes

Which statement correctly describes the difference between active transport and diffusion?

  1. Active transport occurs only in non-living systems.
  2. Both processes move substances only from low to high concentration.
  3. Diffusion requires energy while active transport does not.
  4. Active transport moves substances against a concentration gradient and requires energy. Correct answer.

Explanation

Active transport uses energy from respiration to move ions or molecules against their concentration gradient, often through carrier proteins. Diffusion is passive and moves particles down a concentration gradient.

Question 17Cells and Cell Processes

A red blood cell is placed in distilled water. Which observation is expected?

  1. It stays the same size because water cannot cross its membrane.
  2. It shrinks and becomes crenated.
  3. It develops a cell wall to resist the pressure.
  4. It swells and bursts because it has no cell wall. Correct answer.

Explanation

Distilled water has a higher water potential than the cytoplasm, so water enters the red blood cell by osmosis. Without a rigid cell wall to resist the pressure, the membrane stretches and bursts.

Question 18Cells and Cell Processes

Which adaptation of a sperm cell is most directly related to its function?

  1. A tail that enables it to swim towards the egg Correct answer.
  2. A large permanent vacuole
  3. A thick cellulose cell wall
  4. A large number of chloroplasts

Explanation

The tail, or flagellum, allows the sperm to move through the female reproductive tract to reach and fertilise the egg. Its many mitochondria supply the energy for this movement.

Question 19Cells and Cell Processes

Which change to an enzyme's environment would most likely reduce its activity by altering the charges in its active site?

  1. An increase in the amount of substrate
  2. A small rise in temperature from 30 to 35 degrees Celsius
  3. A decrease in the size of the reaction vessel
  4. A large change in pH away from the optimum Correct answer.

Explanation

Enzymes have an optimum pH, and changes in hydrogen ion concentration alter the charges and bonds within the active site. This can change its shape so the substrate no longer fits, reducing activity.

Question 20Cells and Cell Processes

A student calculates the magnification of a drawing where the image of a cell is 40 mm wide and the actual cell is 0.05 mm wide. What is the magnification?

  1. 8000 times
  2. 800 times Correct answer.
  3. 80 times
  4. 8 times

Explanation

Magnification equals image size divided by actual size. Dividing 40 mm by 0.05 mm gives 800, so the drawing is magnified 800 times.

Question 21Cells and Cell Processes

Two cells are viewed with the same microscope. Cell A appears twice as wide as cell B on the image. Which conclusion is valid?

  1. Cell A is twice as long as cell B.
  2. Cell A has twice as many mitochondria as cell B.
  3. Cell A is twice as wide as cell B in real life. Correct answer.
  4. Cell B has a thicker cell wall than cell A.

Explanation

Because both cells are viewed at the same magnification, the ratio of their image sizes equals the ratio of their actual sizes. A cell appearing twice as wide on the image is therefore twice as wide in reality.

Question 22Cells and Cell Processes

A cell is placed in a solution that is isotonic with its cytoplasm. Which statement best describes the net movement of water?

  1. Water moves out of the cell faster than it enters.
  2. There is no net movement of water across the membrane. Correct answer.
  3. Water moves into the cell faster than it leaves.
  4. Water molecules stop crossing the membrane entirely.

Explanation

In an isotonic solution the water potential outside equals that inside the cell. Water molecules still cross the membrane in both directions, but at equal rates, so there is no net change in volume.

Question 23Cells and Cell Processes

An enzyme is added to a reaction mixture containing excess substrate. The rate is measured and then the enzyme concentration is doubled. Which prediction is most likely, provided substrate remains in excess?

  1. The rate increases without limit as enzyme is added.
  2. The rate stays the same because the enzyme is unchanged.
  3. The rate roughly doubles because more active sites are available. Correct answer.
  4. The rate falls because the enzyme molecules compete with each other.

Explanation

When substrate is in excess, the number of substrate molecules converted per second depends on the number of active sites available. Doubling the enzyme concentration roughly doubles the number of active sites and so doubles the rate.

Question 24Cells and Cell Processes

Which comparison of prokaryotic and eukaryotic cells is correct?

  1. Both cell types contain a membrane-bound nucleus.
  2. Prokaryotic cells have membrane-bound nuclei while eukaryotic cells do not.
  3. Prokaryotic cells lack a membrane-bound nucleus while eukaryotic cells have one. Correct answer.
  4. Neither cell type contains genetic material.

Explanation

Prokaryotic cells keep their DNA in a single circular chromosome free in the cytoplasm, with no nuclear membrane. Eukaryotic cells enclose their chromosomes within a true nucleus bounded by a double membrane.

Question 25Cells and Cell Processes

A plant cell with a cell wall is placed in a strong sugar solution. Which sequence of events is most likely?

  1. Water enters, the cell becomes turgid, and the wall bursts.
  2. Water leaves, the vacuole shrinks, and the membrane pulls away from the wall. Correct answer.
  3. Water leaves and the cell wall shrinks first, then the membrane.
  4. Solutes move in by osmosis and the cell swells.

Explanation

The strong sugar solution has a lower water potential than the cell sap, so water leaves the cell by osmosis. The vacuole and cytoplasm shrink, and the membrane detaches from the rigid wall in a process called plasmolysis.

Question 26Cells and Cell Processes

A student views a cell under a microscope and sees many small green structures inside it. Which process takes place mainly in these structures?

  1. Digestion of starch
  2. Respiration
  3. Synthesis of proteins
  4. Photosynthesis Correct answer.

Explanation

The green structures are chloroplasts, which contain the pigment chlorophyll. Chlorophyll absorbs light energy, and this energy is used to combine carbon dioxide and water into glucose during photosynthesis.

Question 27Cells and Cell Processes

A single-celled organism lives in pond water. Its cell has no nucleus and no mitochondria, but it has a cell wall and a loop of DNA. How is this organism best classified?

  1. As an animal, because it is a single cell with no chloroplasts
  2. As a plant, because it has a cell wall and lives in water
  3. As a fungus, because it has a cell wall and DNA
  4. As a prokaryote, because it lacks a nucleus and membrane-bound organelles Correct answer.

Explanation

Prokaryotic cells are defined by the absence of a membrane-bound nucleus and of membrane-bound organelles such as mitochondria. Their DNA forms a single loop in the cytoplasm, and many also have a cell wall, so the described features match a prokaryote.

Question 28Cells and Cell Processes

A student investigates osmosis using potato cylinders. Each cylinder is weighed, placed in a different sugar solution for one hour, then reweighed. The results are shown below. Concentration of sugar solution (mol/dm3): 0.0, 0.2, 0.4, 0.6, 0.8 Change in mass of cylinder (%): +9, +4, 0, -5, -11 Which conclusion is best supported by these results?

  1. The potato tissue has the same water potential as a sugar solution of about 0.4 mol/dm3 Correct answer.
  2. Sugar enters the potato cells most rapidly at 0.8 mol/dm3
  3. The potato tissue loses water in every solution tested
  4. The rate of water uptake increases as sugar concentration increases

Explanation

At 0.4 mol/dm3 the change in mass is zero, meaning water enters and leaves the tissue at equal rates. At this point the external solution has the same water potential as the potato cell contents, so there is no net movement of water.

Question 29Cells and Cell Processes

An enzyme is mixed with excess substrate at its optimum pH and temperature. The initial rate of reaction is measured. A competitive inhibitor is then added in a concentration equal to that of the substrate. Which change is expected, and why?

  1. The rate stays the same because the substrate is present in excess
  2. The rate rises because the inhibitor provides an alternative reaction pathway
  3. The rate falls because inhibitor molecules occupy the active site, but a higher substrate concentration can restore the rate Correct answer.
  4. The rate falls because the inhibitor permanently changes the shape of the active site

Explanation

A competitive inhibitor has a shape similar to the substrate and binds to the active site, so fewer enzyme molecules are available to form enzyme-substrate complexes and the rate decreases. Because the inhibitor and substrate compete for the same site, increasing the substrate concentration reduces the chance of inhibitor binding and can restore the original rate.

Question 30Cells and Cell Processes

A student examines a cell and records that it contains many mitochondria but no chloroplasts, and that its genetic material is enclosed within a nuclear membrane. Which type of cell is being described?

  1. A plant root cell, because it has mitochondria but no chloroplasts
  2. A bacterial cell, because it has many mitochondria
  3. An animal cell, because it lacks chloroplasts and has a true nucleus Correct answer.
  4. A prokaryotic cell, because it has no chloroplasts

Explanation

A nucleus bounded by a membrane shows the cell is eukaryotic, and the absence of chloroplasts means it cannot photosynthesise, which fits an animal cell. Mitochondria are present in both plant and animal cells, so their presence alone does not identify the cell type.

Question 31Nutrition and Digestion

Which nutrient is the body's main immediate source of energy for cellular respiration?

  1. Vitamin C
  2. Carbohydrate Correct answer.
  3. Protein
  4. Water

Explanation

Carbohydrates are broken down to glucose, which cells oxidise in respiration to release energy quickly. Protein is used mainly for growth and repair, while vitamins and water do not supply energy.

Question 32Nutrition and Digestion

Which enzyme begins the chemical digestion of starch in the human mouth?

  1. Trypsin
  2. Pepsin
  3. Lipase
  4. Amylase Correct answer.

Explanation

Salivary amylase hydrolyses starch into maltose as food is chewed, so starch digestion starts in the mouth. Pepsin and trypsin act on proteins in the stomach and small intestine, and lipase acts on fats.

Question 33Nutrition and Digestion

What is the main role of bile in digestion?

  1. It breaks down proteins into amino acids
  2. It converts starch into simple sugars
  3. It emulsifies fats into small droplets to increase surface area Correct answer.
  4. It hydrolyses fats into fatty acids and glycerol

Explanation

Bile contains bile salts that physically emulsify large fat globules into many small droplets, greatly increasing the surface area for lipase. Bile is alkaline and neutralises stomach acid, but it carries no digestive enzymes of its own.

Question 34Nutrition and Digestion

Which structure increases the surface area of the small intestine for absorption?

  1. Nephrons
  2. Villi Correct answer.
  3. Alveoli
  4. Rugae of the stomach

Explanation

The lining of the small intestine is folded into finger-like villi, each covered with microvilli, producing a very large absorptive surface. Alveoli belong to the lungs and nephrons to the kidneys.

Question 35Nutrition and Digestion

Which food test gives a brick-red colour when a reducing sugar such as glucose is present?

  1. Benedict's test Correct answer.
  2. Biuret test
  3. Iodine test
  4. Emulsion test

Explanation

Benedict's solution contains copper(II) ions that are reduced to copper(I) oxide by reducing sugars on heating, giving a brick-red precipitate. The biuret test detects protein and iodine detects starch.

Question 36Nutrition and Digestion

Which type of tooth has a broad, flat crown suited to crushing and grinding food?

  1. Incisor
  2. Incisor and canine equally
  3. Premolar Correct answer.
  4. Canine

Explanation

Premolars and molars have wide, flat crowns with cusps that crush and grind food, which increases the surface area for enzymes. Incisors are chisel-shaped for cutting and canines are pointed for tearing.

Question 37Nutrition and Digestion

Which vitamin is needed for the absorption of calcium and the healthy formation of bone?

  1. Vitamin B1
  2. Vitamin C
  3. Vitamin D Correct answer.
  4. Vitamin A

Explanation

Vitamin D promotes the absorption of calcium and phosphate from the gut, which is needed for mineralising bone. A deficiency causes rickets in children, with soft, deformed bones.

Question 38Nutrition and Digestion

A student chews a piece of bread for several minutes and notices it begins to taste sweet. Which change explains this?

  1. Bile salts convert fat into fatty acids
  2. Pepsin converts protein into amino acids
  3. Salivary amylase converts some starch into maltose Correct answer.
  4. Hydrochloric acid converts starch into glucose

Explanation

Salivary amylase hydrolyses starch in the bread into maltose, a sugar that tastes sweet. This is why starchy foods taste sweeter the longer they are chewed.

Question 39Nutrition and Digestion

Which feature of the small intestine lining is most directly responsible for absorbing glucose and amino acids into the blood?

  1. A single layer of epithelial cells with microvilli Correct answer.
  2. A thick, muscular outer wall
  3. Large numbers of goblet cells secreting mucus
  4. Presence of hydrochloric acid

Explanation

The epithelium of the villi is only one cell thick and bears microvilli, so dissolved nutrients diffuse a short distance into the rich blood capillaries inside each villus. The thin barrier and dense capillary network make absorption efficient.

Question 40Nutrition and Digestion

Which statement best describes the role of hydrochloric acid in the stomach?

  1. It converts maltose into glucose
  2. It digests fats into glycerol and fatty acids
  3. It kills many ingested bacteria and provides an acidic pH for pepsin Correct answer.
  4. It neutralises bile entering from the liver

Explanation

Hydrochloric acid lowers the stomach pH to about 2, which kills many swallowed microbes and provides the optimum acidic conditions for pepsin to work. It also helps convert inactive pepsinogen into active pepsin.

Question 41Nutrition and Digestion

Which pair of organs produces and stores bile respectively?

  1. Salivary glands and duodenum
  2. Pancreas and stomach
  3. Liver and gall bladder Correct answer.
  4. Stomach and pancreas

Explanation

The liver produces bile continuously, and it is stored and concentrated in the gall bladder before being released into the duodenum. The pancreas produces pancreatic juice containing enzymes, not bile.

Question 42Nutrition and Digestion

Which enzyme digests proteins in the stomach?

  1. Lipase
  2. Pepsin Correct answer.
  3. Amylase
  4. Maltase

Explanation

Pepsin is a protease secreted as inactive pepsinogen and activated by hydrochloric acid in the stomach, where it breaks proteins into shorter polypeptides. Lipase, maltase and amylase act on fats, maltose and starch respectively.

Question 43Nutrition and Digestion

A person with a blocked bile duct may pass pale, fatty faeces. Which explanation is most likely?

  1. Water absorption in the colon is reduced
  2. Protein digestion stops completely in the stomach
  3. Fat is not emulsified, so lipase acts less efficiently Correct answer.
  4. Starch is no longer digested by amylase in the mouth

Explanation

Without bile, large fat globules are not broken into small droplets, so lipase has less surface area to act on and much fat remains undigested. The unabsorbed fat passes out in the faeces, making them pale and greasy.

Question 44Nutrition and Digestion

Which deficiency disease results from a lack of vitamin C in the diet?

  1. Rickets
  2. Scurvy Correct answer.
  3. Anaemia
  4. Night blindness

Explanation

Vitamin C is needed for the synthesis of collagen, so a deficiency causes scurvy with bleeding gums, slow wound healing and weak blood vessels. Rickets results from vitamin D deficiency and night blindness from vitamin A deficiency.

Question 45Nutrition and Digestion

Which description best explains why peristalsis is important in the alimentary canal?

  1. It secretes bile from the liver
  2. It increases the rate of enzyme production
  3. It absorbs water from the colon
  4. It moves food along the gut and mixes it with digestive juices Correct answer.

Explanation

Peristalsis is a wave of alternating circular and longitudinal muscle contractions that pushes the contents forward and mixes them with enzymes. This ensures food meets each digestive juice in turn and moves steadily through the tract.

Question 46Nutrition and Digestion

A student tests a food sample with iodine solution and it turns blue-black. What does this indicate?

  1. The sample contains a reducing sugar
  2. The sample contains protein
  3. The sample contains fat
  4. The sample contains starch Correct answer.

Explanation

Iodine molecules slot into the coiled structure of amylose in starch, producing a blue-black colour. This is the standard positive result for starch, while different reagents are needed to detect protein, reducing sugar and fat.

Question 47Nutrition and Digestion

Which of these describes the action of an enzyme such as maltase?

  1. It raises the temperature of the reaction mixture
  2. It lowers the activation energy needed for the reaction Correct answer.
  3. It changes the products of the reaction
  4. It is used up in the reaction it catalyses

Explanation

Enzymes are biological catalysts that lower the activation energy required for a reaction, so it proceeds faster at body temperature. The enzyme is not consumed and does not alter the nature of the products.

Question 48Nutrition and Digestion

Which structure prevents food from entering the trachea during swallowing?

  1. Uvula
  2. Duodenum
  3. Epiglottis Correct answer.
  4. Oesophagus

Explanation

During swallowing the epiglottis folds down over the opening of the trachea, so the bolus passes into the oesophagus instead of the airway. The uvula helps close off the nasal cavity, and the duodenum is part of the small intestine.

Question 49Nutrition and Digestion

Which statement about the digestion and absorption of fats is correct?

  1. Fats are digested to amino acids and absorbed into capillaries
  2. Fats are digested to glucose and absorbed into the liver
  3. Fats are digested to fatty acids and glycerol and absorbed into lacteals Correct answer.
  4. Fats are digested to glycerol and absorbed unchanged into veins

Explanation

Lipase hydrolyses fats into fatty acids and glycerol, which combine with bile salts to form micelles absorbed by the villi. Inside the villi they are re-formed into fats and enter the lacteals of the lymphatic system rather than the blood capillaries.

Question 50Nutrition and Digestion

An enzyme from the small intestine works best at pH 8. Which condition would most reduce its rate of reaction?

  1. Raising the temperature from 20 °C to 37 °C
  2. Increasing the enzyme concentration
  3. Adding more substrate to the mixture
  4. Placing it in a solution of pH 2 Correct answer.

Explanation

Each enzyme has an optimum pH, and a strongly acidic pH of 2 would alter the shape of the active site so the substrate no longer fits, denaturing the enzyme. Warming towards 37 °C, adding substrate or enzyme would normally increase the rate.