GCSE Biology Topic 2: Organisation MCQs – 30 Practice Questions with Answers (AQA 8461)
Free practice for AQA GCSE Biology 8461 on levels of organisation, digestion, the heart and blood, health and disease, and plant transport, with a short explanation after every question.
Levels of Organisation and Digestion
Q1. A group of similar cells working together in a leaf makes up which level of organisation?
- (A) An organism
- (B) An organ system
- (C) A tissue
- (D) A single cell
Show Answer
Answer: C – A tissue is a group of cells with a similar structure and function, and tissues combine to form organs.
Q2. Which order correctly lists levels of organisation from smallest to largest?
- (A) Organ, tissue, cell, organ system, organism
- (B) Cell, tissue, organ, organ system, organism
- (C) Tissue, cell, organ system, organ, organism
- (D) Cell, organ, tissue, organism, organ system
Show Answer
Answer: B – Cells form tissues, tissues form organs, organs work together in organ systems, and organ systems make up an organism.
Q3. Amylase is released in the mouth and the small intestine. What does it break down, and into what?
- (A) Proteins into amino acids
- (B) Lipids into glycerol and fatty acids
- (C) Simple sugars into starch
- (D) Starch into simple sugars
Show Answer
Answer: D – Amylase is a carbohydrase, so it breaks down the carbohydrate starch into smaller soluble sugars that can be absorbed.
Q4. A meal rich in meat is digested in the stomach and small intestine. Which enzyme group breaks the proteins in the meat down?
- (A) Carbohydrases, which act on starch
- (B) Lipases, which act on fats
- (C) Bile salts, which emulsify fats
- (D) Proteases, which break proteins into amino acids
Show Answer
Answer: D – Proteases catalyse the breakdown of proteins into amino acids, the small soluble products that the blood can absorb.
Q5. Why does bile improve the digestion of fats even though bile itself is not an enzyme?
- (A) Bile breaks fats directly into amino acids during normal activity for the organism described under the conditions given
- (B) Bile absorbs fats through the stomach wall
- (C) Bile neutralises acid and splits fat into tiny droplets, giving lipase a much larger surface to work on
- (D) Bile turns fats into starch for storage
Show Answer
Answer: C – Bile is alkaline, so it neutralises stomach acid, and it emulsifies fat into small droplets, increasing the surface area for lipase action.
Q6. A student tests a food sample with iodine solution and it stays brown-orange, but Benedict solution turns brick red on heating. What does this combination suggest?
- (A) The sample contains starch but no sugars
- (B) The sample contains sugars but no starch
- (C) The sample contains protein but no carbohydrate
- (D) The sample contains lipid but no carbohydrate
Show Answer
Answer: B – Iodine turns blue-black with starch, so no colour change means starch is absent, while a brick-red Benedict result shows sugars are present.
Q7. A student investigates how pH affects amylase by sampling a starch mixture every 30 seconds and testing each sample with iodine. What is the student measuring?
- (A) The time taken for starch to disappear completely at each pH
- (B) The mass of amylase used at each pH
- (C) The volume of iodine needed at each pH
- (D) The temperature of the water bath at each pH
Show Answer
Answer: A – Repeated iodine tests show when starch is no longer present, so the time to complete digestion gives the rate at that pH.
Q8. Digestive enzymes are proteins with a particular active site shape. What happens to their rate of reaction when the pH moves far from the optimum?
- (A) The rate falls because the active site shape changes and the substrate fits less well
- (B) The rate rises steadily without limit
- (C) The rate stays exactly the same at every pH
- (D) The enzyme changes into a different substrate in this type of tissue over a short period of time
Show Answer
Answer: A – A large pH change alters the shape of the active site, so the substrate no longer fits well and the reaction slows.
The Heart, Blood Vessels and Blood
Q9. In the double circulatory system, what does the right side of the heart do?
- (A) It pumps blood around the whole body except the lungs
- (B) It pumps blood to the lungs for gas exchange
- (C) It pumps blood directly to the brain only
- (D) It collects blood from the coronary arteries
Show Answer
Answer: B – The right ventricle pumps deoxygenated blood to the lungs, where carbon dioxide is released and oxygen is taken up.
Q10. Why is the wall of the left ventricle much thicker than the wall of the right ventricle?
- (A) The left ventricle stores extra blood for emergencies in a healthy organism at ordinary temperatures
- (B) The left ventricle contains the pacemaker cells
- (C) The left ventricle is filled with deoxygenated blood
- (D) The left ventricle must generate enough pressure to pump blood around the entire body
Show Answer
Answer: D – Blood leaving the left ventricle travels through the whole body, so its thicker muscle wall can produce the higher pressure that journey needs.
Q11. Which blood vessel carries oxygenated blood from the lungs back towards the heart?
- (A) The vena cava
- (B) The pulmonary artery
- (C) The pulmonary vein
- (D) The aorta
Show Answer
Answer: C – The pulmonary vein is the exception to the usual pattern: it carries oxygenated blood from the lungs into the left side of the heart.
Q12. A capillary wall is only one cell thick. How does this help its function?
- (A) It lets blood flow at very high pressure
- (B) It prevents any exchange of substances
- (C) It carries blood back to the heart without valves
- (D) It lets substances diffuse quickly between blood and surrounding cells
Show Answer
Answer: D – A one-cell-thick wall gives a very short diffusion distance, so oxygen, nutrients and wastes exchange rapidly with nearby tissues.
Q13. Which structural feature of arteries suits them to carrying blood at high pressure away from the heart?
- (A) Thin walls with many valves
- (B) Wide lumens and very slow flow
- (C) Thick muscular and elastic walls with a narrow lumen
- (D) Walls one cell thick with pores under normal conditions
Show Answer
Answer: C – Thick, elastic, muscular walls withstand high pressure and help maintain flow, while the narrower lumen keeps pressure up.
Q14. Veins carry blood back to the heart at low pressure. Which feature stops blood flowing backwards in a vein?
- (A) Valves inside the vessel
- (B) A thick elastic wall
- (C) A one-cell-thick wall
- (D) A narrow lumen with no valves
Show Answer
Answer: A – Valves in veins open to let blood pass towards the heart and close to prevent backflow when pressure is low.
Q15. A blood sample is examined and one cell type has no nucleus and a biconcave disc shape. Which component is it, and what is its job?
- (A) A white blood cell, which defends against pathogens
- (B) A red blood cell, which carries oxygen around the body
- (C) A platelet, which helps blood to clot
- (D) A plasma cell, which carries dissolved nutrients
Show Answer
Answer: B – Red blood cells lose their nucleus as they mature, and their biconcave shape gives a large surface for oxygen uptake and release.
Coronary Heart Disease, Health and Lifestyle
Q16. In coronary heart disease, fatty material builds up inside the coronary arteries. What is the direct consequence for the heart muscle?
- (A) The heart muscle receives extra glucose from the fatty deposits in a typical living organism during normal activity
- (B) The heart valves open more widely than normal
- (C) The pacemaker cells stop producing red blood cells
- (D) The heart muscle receives less oxygen because blood flow through the narrowed arteries is reduced
Show Answer
Answer: D – Narrowed coronary arteries carry less blood, so the heart muscle is starved of the oxygen it needs to respire and contract.
Q17. A patient with narrowed coronary arteries is fitted with a stent. What does the stent do?
- (A) It dissolves fatty material with enzymes during normal activity
- (B) It holds the artery open so blood can flow through it
- (C) It lowers blood cholesterol levels
- (D) It replaces a faulty heart valve
Show Answer
Answer: B – A stent is a small mesh tube inserted into the artery to keep it open and restore blood flow to the heart muscle.
Q18. Statins are prescribed to many people at risk of cardiovascular disease. How do statins help?
- (A) They reduce blood cholesterol, slowing the deposit of fatty material in arteries
- (B) They replace damaged heart valves with mechanical ones
- (C) They increase the heart rate permanently
- (D) They destroy viruses in the bloodstream
Show Answer
Answer: A – By lowering blood cholesterol levels, statins slow down the rate at which fatty deposits narrow the arteries.
Q19. Health is described as a state of physical and mental well-being, not simply the absence of disease. Which example shows two types of disease interacting?
- (A) A broken bone healing after a fall
- (B) A cut closing as platelets form a clot under the conditions given
- (C) A virus living inside cells triggering a cancer
- (D) A muscle growing larger with exercise
Show Answer
Answer: C – Some viruses that live in cells can trigger cancers, showing how an infectious disease can lead to a non-communicable disease.
Q20. A scatter diagram shows a strong link between smoking and lung disease in a large population. What can a scientist safely conclude from correlation alone?
- (A) The two variables are linked, but a causal mechanism still needs separate evidence
- (B) Smoking is proven to cause lung disease in every individual in this type of tissue over a short period of time
- (C) Lung disease causes people to start smoking
- (D) No link exists between the two variables
Show Answer
Answer: A – Correlation shows variables changing together, but for some risk factors a causal mechanism has been proven and for others it has not, so correlation alone does not prove cause.
Q21. Which lifestyle factor is linked to Type 2 diabetes as a risk factor?
- (A) Short height
- (B) Blood group
- (C) Obesity
- (D) Eye colour
Show Answer
Answer: C – Obesity is identified as a risk factor for Type 2 diabetes, alongside diet and exercise patterns that influence cardiovascular disease.
Q22. What is the difference between a benign tumour and a malignant tumour?
- (A) Benign tumours spread through the blood, while malignant tumours stay in one place
- (B) Benign tumours are always caused by viruses, while malignant tumours are always inherited
- (C) Benign tumours are contained in one area and do not invade other tissues, while malignant tumours invade neighbours and form secondary tumours
- (D) Benign tumours grow faster than malignant tumours
Show Answer
Answer: C – Cancer results from uncontrolled growth and division; benign growths stay contained, usually within a membrane, whereas malignant cells invade nearby tissues and spread.
Plant Tissues and Transport
Q23. Which plant tissue is found at the growing tips of shoots and roots?
- (A) Meristem tissue
- (B) Spongy mesophyll
- (C) Epidermal tissue
- (D) Palisade mesophyll
Show Answer
Answer: A – Meristem tissue at shoot and root tips contains undifferentiated cells that divide and then differentiate into other plant tissues.
Q24. Guard cells surround each stoma on a leaf. What do guard cells control?
- (A) The transport of sugars in the phloem
- (B) The opening and closing of the stoma, and therefore gas exchange and water loss
- (C) The production of starch in the roots
- (D) The uptake of mineral ions by root hairs in a normal healthy cell under normal conditions
Show Answer
Answer: B – Guard cells change shape to open or close the stoma, controlling gas exchange for photosynthesis and limiting water loss from the leaf.
Q25. Transpiration is fastest on a hot, dry, windy day. Which combination of conditions explains this?
- (A) High temperature, low humidity and moving air all increase water loss from leaves
- (B) Low temperature, high humidity and still air all increase water loss from leaves
- (C) High light intensity alone stops water loss from leaves
- (D) Low humidity alone closes all stomata permanently
Show Answer
Answer: A – Heat speeds evaporation, dry air maintains a steep gradient for water vapour, and wind sweeps vapour away, so all three raise the transpiration rate.
Q26. A plant is kept in dim light with its stomata mostly closed. What will happen to its transpiration rate and its uptake of carbon dioxide?
- (A) Both will fall, because closed stomata limit water loss and gas exchange
- (B) Both will rise sharply
- (C) Transpiration will rise while carbon dioxide uptake falls in most ordinary cells
- (D) Transpiration will fall while carbon dioxide uptake rises
Show Answer
Answer: A – Stomata are the shared route for water vapour leaving and carbon dioxide entering, so closing them reduces both movements.
Q27. Sugars made in a leaf are moved to a growing root tip. What is this movement called, and which tissue carries it?
- (A) Transpiration through xylem when conditions stay suitable
- (B) Translocation through phloem
- (C) Diffusion through epidermis
- (D) Osmosis through guard cells
Show Answer
Answer: B – Translocation is the movement of dissolved sugars through phloem tissue from leaves to parts of the plant that use or store them.
Q28. How does the structure of phloem allow cell sap to move from cell to cell?
- (A) Phloem cells are dead hollow tubes strengthened by lignin
- (B) Phloem cells have a thick waxy cuticle on their surface
- (C) Phloem cells contain many chloroplasts for photosynthesis
- (D) Phloem cells are elongated tubes with pores in their end walls
Show Answer
Answer: D – Phloem is made of elongated cells joined end to end, and pores in the end walls let dissolved sugars pass from one cell to the next.
Q29. A student measures water uptake by a shoot using a potometer on two days: a still humid day and a windy dry day. Which result is expected?
- (A) Uptake is higher on the still humid day because stomata stay open longer during normal activity
- (B) Uptake is the same on both days because temperature is unchanged
- (C) Uptake stops on the windy dry day because xylem collapses
- (D) Uptake is higher on the windy dry day because transpiration pulls more water up the shoot
Show Answer
Answer: D – Faster transpiration on the windy dry day increases the pull on water, so the shoot takes up water more rapidly, as shown by the potometer.
Q30. A leaf cross-section shows a layer of tightly packed cells just under the upper epidermis. Which tissue is this, and why is it packed tightly?
- (A) Spongy mesophyll, to allow gases to circulate freely for the organism described
- (B) Palisade mesophyll, to trap as much light as possible for photosynthesis
- (C) Xylem, to carry water upwards
- (D) Epidermis, to prevent water loss
Show Answer
Answer: B – Palisade mesophyll cells are packed closely under the upper surface, where light is strongest, and each contains many chloroplasts for photosynthesis.
Work through any questions you missed again, then revise those areas before moving on to the next topic.