GCSE Biology Topic 1: Cell Biology MCQs – 30 Practice Questions with Answers (AQA 8461)
Free practice for AQA GCSE Biology 8461 on cell structure, division, stem cells and transport across membranes, with a short explanation after every question.
Cell Structure and Microscopy
Q1. Which three parts are found in both a typical animal cell and a typical plant cell?
- (A) Cell wall, chloroplasts and a permanent vacuole
- (B) Plasmids, a cell wall and chloroplasts
- (C) Nucleus, cytoplasm and a cell membrane
- (D) A permanent vacuole, plasmids and a nucleus
Show Answer
Answer: C – Animal and plant cells both contain a nucleus, cytoplasm and a cell membrane, while a cell wall, chloroplasts and a permanent vacuole are extra features of plant cells.
Q2. A student looks at a bacterial cell under a microscope. Which feature shows that it is prokaryotic rather than eukaryotic?
- (A) It has a cell membrane around its cytoplasm
- (B) Its genetic material is a single loop of DNA floating free in the cytoplasm
- (C) Its cytoplasm contains ribosomes for making proteins
- (D) It is surrounded by a protective cell wall
Show Answer
Answer: B – In a prokaryotic bacterial cell the DNA is a single loop that is not enclosed inside a nucleus, whereas eukaryotic cells hold their DNA inside a nucleus.
Q3. Why does a plant cell keep its shape even when its vacuole fills with water?
- (A) Its chloroplasts absorb the extra water
- (B) Its nucleus divides to make room
- (C) Its cell membrane dissolves and reforms around the vacuole when conditions stay suitable
- (D) Its cellulose cell wall pushes back against the swelling contents
Show Answer
Answer: D – The rigid wall made of cellulose strengthens the plant cell, so it resists bursting as water enters and the cell becomes turgid.
Q4. Which sub-cellular structure is the site where most of the energy for a cell is transferred from glucose?
- (A) The ribosome, where proteins are assembled
- (B) The permanent vacuole, where cell sap is stored
- (C) The nucleus, where genes are stored
- (D) The mitochondrion, where aerobic respiration takes place
Show Answer
Answer: D – Mitochondria are the sites of aerobic respiration, the process that transfers energy from glucose for the cell to use.
Q5. A leaf cell is placed in bright light. Which structure inside it captures light energy for making food?
- (A) The vacuole filled with cell sap
- (B) The ribosome floating in the cytoplasm during normal activity
- (C) The chloroplast containing green pigment
- (D) The cell wall surrounding the cell
Show Answer
Answer: C – Chloroplasts contain chlorophyll, the pigment that absorbs light energy so the leaf cell can carry out photosynthesis.
Q6. What job do ribosomes carry out in every living cell?
- (A) They store sugars for later release
- (B) They join amino acids together to build new proteins
- (C) They control which substances cross the membrane for the organism described
- (D) They split the cell into two during division
Show Answer
Answer: B – Ribosomes are the tiny structures where protein synthesis happens, assembling amino acids in the order set by the genes.
Q7. An electron microscope image shows far more detail inside a cell than a light microscope image of the same cell. What explains the difference?
- (A) The electron microscope has much higher magnification and resolving power
- (B) The electron microscope uses a brighter lamp
- (C) The light microscope cannot show living cells at all
- (D) The electron microscope stains the cell more strongly
Show Answer
Answer: A – Electron microscopes magnify far more and can separate much finer detail than light microscopes, revealing sub-cellular structures that light microscopes cannot resolve.
Q8. A micrograph shows a cell that is 40 mm long in the image, and the magnification used was 400 times. What is the real length of the cell?
- (A) 0.1 mm
- (B) 16000 mm
- (C) 400 mm
- (D) 0.01 mm
Show Answer
Answer: A – Real size equals image size divided by magnification, so 40 divided by 400 gives 0.1 mm.
Specialised Cells and Differentiation
Q9. A sperm cell has a long tail and many mitochondria in its middle section. How do these features suit its job?
- (A) The tail stores food and the mitochondria digest the egg
- (B) The tail swims the cell towards the egg and the mitochondria supply energy for that movement
- (C) The tail protects the nucleus and the mitochondria make new genes over a short period of time
- (D) The tail carries oxygen and the mitochondria store water
Show Answer
Answer: B – The tail propels the sperm cell, and the many mitochondria transfer the energy needed to keep it swimming until it reaches an egg cell.
Q10. Which adaptation helps a nerve cell carry electrical signals quickly over a long distance?
- (A) A large central vacuole that stores signals in a healthy organism
- (B) A thick cellulose wall that blocks signals
- (C) Many chloroplasts that trap light energy
- (D) A long fibre with branches that connect to other cells
Show Answer
Answer: D – The long fibre of a nerve cell, with branches at its ends, lets impulses travel rapidly from one part of the body to another and pass to neighbouring cells.
Q11. Why do root hair cells have a very large surface area?
- (A) To catch more sunlight for photosynthesis
- (B) To hold the plant upright in strong wind
- (C) To absorb water and mineral ions from the soil more effectively
- (D) To store starch made in the leaves
Show Answer
Answer: C – The long, thin projection of each root hair cell greatly increases the surface in contact with soil water, speeding up uptake by osmosis and active transport.
Q12. Xylem vessels are hollow tubes with thickened walls. Which function does this structure serve in a plant?
- (A) Carrying dissolved sugars from leaves to growing regions in a normal healthy cell
- (B) Opening and closing to control gas exchange
- (C) Dividing to produce new leaves at the shoot tip
- (D) Carrying water and dissolved mineral ions upwards from the roots
Show Answer
Answer: D – Hollow xylem tubes strengthened by lignin form a continuous pipeline that moves water and mineral ions from roots to stems and leaves.
Q13. As an animal embryo develops, its cells become different from one another. What is this process called?
- (A) Binary fission under normal conditions
- (B) Fermentation
- (C) Differentiation
- (D) Translocation
Show Answer
Answer: C – Differentiation is the process by which unspecialised cells develop the particular structures they need for one specialised job.
Q14. Which statement about differentiation in plants and animals is correct?
- (A) Most animal cells differentiate early in life, while many plant cells keep the ability to differentiate throughout life
- (B) Plant cells lose the ability to differentiate as soon as a seed germinates
- (C) Animal cells differentiate only after injury, while plant cells never differentiate
- (D) Differentiation happens only in stem cells taken from adult bone marrow
Show Answer
Answer: A – Most animal cells specialise at an early stage, whereas many plant cells, including those in meristems, retain the ability to differentiate for the whole life of the plant.
Q15. A gardener wants many identical copies of a rare plant with disease-resistant leaves. Which plant tissue could provide cells for this?
- (A) Bark, because its dead cells fall off easily
- (B) Meristem tissue, because its cells can still become any type of plant cell
- (C) Xylem, because its hollow tubes carry water
- (D) Spongy mesophyll, because its cells trap light when conditions stay suitable
Show Answer
Answer: B – Meristem cells are undifferentiated and can give rise to any plant cell type, so clones grown from them are quick and economical to produce in large numbers.
Mitosis, Stem Cells and Chromosomes
Q16. Before a body cell divides, its DNA is copied. What is the outcome of the division that follows?
- (A) Four cells each with half the number of chromosomes in a typical living organism
- (B) One cell with twice as many chromosomes as before
- (C) Two cells that each carry a different set of genes
- (D) Two cells that are genetically identical to the parent cell
Show Answer
Answer: D – In mitosis the doubled genetic material is shared equally, so the two daughter cells are genetically identical to each other and to the parent cell.
Q17. Which sequence puts the main events of the cell cycle in the correct order?
- (A) Nucleus divides, DNA is copied, cytoplasm divides
- (B) DNA is copied, nucleus divides, cytoplasm divides
- (C) Cytoplasm divides, nucleus divides, DNA is copied
- (D) DNA is copied, cytoplasm divides, nucleus divides
Show Answer
Answer: B – The cell first grows and copies its DNA, then mitosis separates one set of chromosomes to each end as the nucleus divides, and finally the cytoplasm divides.
Q18. Chromosomes are found in the nucleus of a body cell. What are chromosomes made of?
- (A) Long molecules of DNA carrying many genes
- (B) Chains of amino acids folded into enzymes
- (C) Layers of cellulose and cell sap
- (D) Small rings of protein called plasmids
Show Answer
Answer: A – Each chromosome is a long DNA molecule, and each carries a large number of genes that control the cell.
Q19. Stem cells from a human embryo are grown in a laboratory. Why are researchers interested in these cells?
- (A) They already contain fully formed organs
- (B) They divide only once and then stop growing
- (C) They can be made to differentiate into most different types of human cell
- (D) They are immune to every known disease
Show Answer
Answer: C – Embryonic stem cells are undifferentiated, so they can be cloned and directed to become most human cell types, offering possible treatments for conditions such as diabetes and paralysis.
Q20. Which use of stem cells raises ethical or religious objections for some people?
- (A) Using stem cells taken from human embryos for research or treatment
- (B) Growing new blood cells from adult bone marrow stem cells
- (C) Cloning rare plants from meristem tissue
- (D) Growing crop plants with disease resistance from meristems in this type of tissue
Show Answer
Answer: A – The use of stem cells taken from human embryos raises ethical or religious objections for some people, whereas adult bone marrow and plant meristem uses raise fewer such objections.
Transport in Cells and Culturing Microorganisms
Q21. Oxygen moves from the air in the lungs into the blood. Which process carries it across the cell membranes there?
- (A) Active transport against a concentration gradient using energy over a short period of time
- (B) Osmosis through a partially permeable membrane
- (C) Diffusion down a concentration gradient from higher to lower concentration
- (D) Translocation through phloem tubes
Show Answer
Answer: C – Oxygen is more concentrated in the air spaces than in the blood, so its particles spread by diffusion across the thin alveolar membranes into the blood.
Q22. A student warms a beaker in which a dye is diffusing through water. What effect does the higher temperature have on the rate of diffusion?
- (A) It slows diffusion because the dye particles clump together
- (B) It stops diffusion because the concentration gradient disappears
- (C) It speeds diffusion because particles gain energy and spread faster
- (D) It reverses diffusion so dye moves back to its starting point
Show Answer
Answer: C – Warmer particles move with more energy and collide and spread more rapidly, so the dye reaches an even distribution sooner.
Q23. Two cubes of the same material have sides of 1 cm and 2 cm. Which cube has the larger surface area to volume ratio, and why does it matter for a single-celled organism?
- (A) The 1 cm cube, and a large ratio lets a single cell exchange enough substances without a transport system
- (B) The 2 cm cube, and a large ratio lets a single cell exchange enough substances without a transport system
- (C) The 1 cm cube, and a large ratio prevents any substances from leaving the cell
- (D) The 2 cm cube, and a large ratio stops diffusion completely
Show Answer
Answer: A – The smaller cube has more surface for each unit of volume, and a single-celled organism relies on that relatively large ratio to take in and release enough molecules by diffusion.
Q24. A piece of potato is placed in a concentrated sugar solution and loses mass. What has happened to water inside the potato cells?
- (A) Water has entered the cells by active transport
- (B) Water has left the cells by osmosis towards the more concentrated solution outside
- (C) Water has been broken down by enzymes in the vacuole
- (D) Water has stayed still because the membrane blocks it in a normal healthy cell under normal conditions
Show Answer
Answer: B – Osmosis is the movement of water from a dilute solution to a concentrated solution through a partially permeable membrane, so water leaves the potato cells and their mass falls.
Q25. Mineral ions in soil water are very dilute, yet root hair cells take them up in large amounts. Which process makes this possible?
- (A) Active transport, because energy from respiration moves ions against their concentration gradient
- (B) Diffusion, because ions always move to the more dilute side under normal conditions in most ordinary cells
- (C) Osmosis, because water carries the ions passively
- (D) Fermentation, because yeast cells release the ions
Show Answer
Answer: A – Active transport uses energy from respiration to move substances from a dilute solution to a more concentrated one, against the gradient, which is how root hairs absorb scarce mineral ions.
Q26. In the human gut, sugar is absorbed into the blood even when the blood already contains more sugar than the gut contents. Which statement explains this?
- (A) Sugar is absorbed by active transport, which can work against a concentration gradient
- (B) Sugar diffuses freely because the gut wall is impermeable
- (C) Sugar moves by osmosis through the gut wall
- (D) Sugar is carried by red blood cells through the gut wall
Show Answer
Answer: A – Only active transport, powered by energy from respiration, can move sugar from a lower concentration in the gut to a higher concentration in the blood.
Q27. Bacteria are grown on an agar plate in a school laboratory. At what maximum temperature should the culture be incubated, and why?
- (A) 37 degrees Celsius, to match human body temperature exactly when conditions stay suitable
- (B) 25 degrees Celsius, to reduce the chance of growing microbes that could harm humans
- (C) 60 degrees Celsius, to kill all bacteria on the plate
- (D) 100 degrees Celsius, to sterilise the agar during growth
Show Answer
Answer: B – School cultures are incubated at no more than 25 degrees Celsius so that any microbes that grow are less likely to be ones that thrive at human body temperature and cause disease.
Q28. A student prepares an uncontaminated bacterial culture. Which step is part of correct aseptic technique?
- (A) Leaving the Petri dish lid fully open on the bench
- (B) Storing the sealed dish right side up so condensation drips onto the agar
- (C) Reusing unsterilised culture medium from a previous lesson
- (D) Passing the inoculating loop through a flame before transferring microbes
Show Answer
Answer: D – Flaming the loop sterilises it, so no unwanted microbes are carried into the culture, while the dish lid is kept closed, taped and stored upside down.
Q29. A bacterial population doubles every 20 minutes in warm nutrient broth. Starting from 100 cells, how many cells will there be after 60 minutes if conditions stay suitable?
- (A) 200 cells
- (B) 300 cells
- (C) 400 cells
- (D) 800 cells
Show Answer
Answer: D – Sixty minutes allows three doublings: 100 becomes 200, then 400, then 800 cells.
Q30. A clear zone appears around an antibiotic disc on a bacterial agar plate. What does the size of the clear zone suggest?
- (A) The antibiotic has no effect on the bacteria at all for the organism described under the conditions given
- (B) The antibiotic inhibited bacterial growth, with a wider zone suggesting a stronger effect in that test
- (C) The bacteria have digested the antibiotic disc
- (D) The agar was sterilised incorrectly before use
Show Answer
Answer: B – In the required practical on antiseptics and antibiotics, bacteria cannot grow near an effective disc, so the clear zone of inhibition shows where growth was prevented.
Work through any questions you missed again, then revise those areas before moving on to the next topic.