AQA GCSE Biology · 4.2

Organisation

50 exam-style questions with answers for 4.2 Organisation in AQA GCSE Biology (spec 8461). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, or read every question and answer below. Not official AQA material.

All 50 questions and answers

Question 1 · Spec 4.2.1 · Principles of organisation
Put these in order of size, smallest first: organ, tissue, cell, organ system. [1 mark]
Answer:
Cell, tissue, organ, organ system.
Question 2 · Spec 4.2.1 · Principles of organisation
Define the term 'tissue'. [1 mark]
Answer:
A group of cells with a similar structure and function.
Question 3 · Spec 4.2.2.1 · Enzymes
Explain why enzymes are described as biological catalysts. [1 mark]
Answer:
They speed up reactions in living organisms without being used up.
Question 4 · Spec 4.2.2.1 · Enzymes
Describe the lock and key theory. [2 marks]
Answer:
The substrate fits into the active site of the enzyme because their shapes are complementary (1); so each enzyme catalyses only one specific reaction (1).
Question 5 · Spec 4.2.2.1 · Enzymes
Explain why enzymes stop working at high temperatures. [2 marks]
Answer:
The shape of the active site changes (the enzyme is denatured) (1); so the substrate no longer fits (1).
Question 6 · Spec 4.2.2.1 · Digestive enzymes
Name the enzyme that breaks down starch and the product formed. [2 marks]
Answer:
Amylase (a carbohydrase) (1); breaks starch into sugars (maltose) (1).
Question 7 · Spec 4.2.2.1 · Digestive enzymes
Where is protease produced in the digestive system? [2 marks]
Answer:
Any two from: stomach (1); pancreas (1); small intestine (1).
Question 8 · Spec 4.2.2.1 · Digestive enzymes
What does lipase break lipids into? [2 marks]
Answer:
Fatty acids (1); and glycerol (1).
Question 9 · Spec 4.2.2.1 · Bile
State two functions of bile. [2 marks]
Answer:
It neutralises hydrochloric acid from the stomach (1); it emulsifies fats into small droplets, increasing the surface area for lipase (1).
Question 10 · Spec 4.2.2.1 · Bile
Where is bile made and stored? [2 marks]
Answer:
Made in the liver (1); stored in the gall bladder (1).
Question 11 · Spec 4.2.2.1 · Required practical 4
Describe the test for starch and a positive result. [2 marks]
Answer:
Add iodine solution (1); it turns from orange-brown to blue-black (1).
Question 12 · Spec 4.2.2.1 · Required practical 4
Describe the test for reducing sugars and a positive result. [2 marks]
Answer:
Add Benedict's reagent and heat in a water bath (1); a positive result changes from blue to green, yellow or brick-red (1).
Question 13 · Spec 4.2.2.1 · Required practical 4
Describe the test for protein and a positive result. [2 marks]
Answer:
Add Biuret reagent (1); it turns from blue to purple (1).
Question 14 · Spec 4.2.2.1 · Required practical 5
Why is iodine tested every 30 seconds in the amylase practical? [1 mark]
Answer:
To find the time taken for all the starch to be digested, when the iodine no longer turns blue-black.
Question 15 · Spec 4.2.2.1 · Required practical 5
Name two control variables in the amylase and pH practical. [2 marks]
Answer:
Any two from: temperature (using a water bath) (1); concentration and volume of amylase (1); concentration and volume of starch (1).
Question 16 · Spec 4.2.2.1 · Rate of reaction
Starch is digested in 120 seconds. Calculate the rate of reaction. [1 mark]
Answer:
Rate = 1 ÷ time = 1 ÷ 120 = 0.0083 s⁻¹.
Question 17 · Spec 4.2.2.2 · The heart
Explain why the heart is described as a double circulatory system. [2 marks]
Answer:
The right side pumps blood to the lungs for gas exchange (1); the left side pumps blood around the rest of the body (1).
Question 18 · Spec 4.2.2.2 · The heart
Why is the wall of the left ventricle thicker than the right? [1 mark]
Answer:
It must pump blood at high pressure all around the body, not just to the lungs.
Question 19 · Spec 4.2.2.2 · The heart
Name the blood vessel that carries oxygenated blood from the lungs to the heart. [1 mark]
Answer:
The pulmonary vein.
Question 20 · Spec 4.2.2.2 · The heart
What controls the natural resting heart rate? [2 marks]
Answer:
A group of cells in the right atrium acting as a pacemaker (1); an artificial electrical pacemaker can correct irregularities (1).
Question 21 · Spec 4.2.2.2 · Blood vessels
Explain how arteries are adapted to their function. [2 marks]
Answer:
Thick muscular and elastic walls (1); to withstand and maintain the high pressure of blood from the heart (1).
Question 22 · Spec 4.2.2.2 · Blood vessels
Explain how veins are adapted to their function. [2 marks]
Answer:
Valves stop blood flowing backwards (1); a large lumen helps low-pressure blood flow (1).
Question 23 · Spec 4.2.2.2 · Blood vessels
Explain how capillaries are adapted for exchange. [2 marks]
Answer:
Walls are one cell thick, giving a short diffusion distance (1); they form a large network close to cells (1).
Question 24 · Spec 4.2.2.2 · Lungs
Explain how alveoli are adapted for gas exchange. [3 marks]
Answer:
Any three from: very large surface area (1); thin walls, one cell thick (1); rich blood supply maintains a concentration gradient (1); ventilation brings fresh air (1).
Question 25 · Spec 4.2.2.2 · Lungs
Describe the pathway of air into the lungs. [2 marks]
Answer:
Air passes down the trachea into the bronchi (1); then into bronchioles and finally the alveoli (1).
Question 26 · Spec 4.2.2.3 · Blood
Name the four components of blood. [2 marks]
Answer:
Plasma and red blood cells (1); white blood cells and platelets (1).
Question 27 · Spec 4.2.2.3 · Blood
Explain how red blood cells are adapted to carry oxygen. [2 marks]
Answer:
Any two from: contain haemoglobin, which binds to oxygen (1); no nucleus, giving more room for haemoglobin (1); biconcave shape gives a large surface area (1).
Question 28 · Spec 4.2.2.3 · Blood
State the function of platelets. [1 mark]
Answer:
They help the blood to clot at a wound.
Question 29 · Spec 4.2.2.3 · Blood
Name three substances carried by plasma. [3 marks]
Answer:
Any three from: carbon dioxide (1); urea (1); glucose and other digested food (1); hormones (1); antibodies (1).
Question 30 · Spec 4.2.2.4 · Coronary heart disease
What is coronary heart disease? [2 marks]
Answer:
Layers of fatty material build up inside the coronary arteries, narrowing them (1); so less oxygen reaches the heart muscle (1).
Question 31 · Spec 4.2.2.4 · Coronary heart disease
State one advantage and one disadvantage of stents. [2 marks]
Answer:
Advantage: keeps the artery open, with a quick recovery (1). Disadvantage: risk of infection or blood clots from surgery (1).
Question 32 · Spec 4.2.2.4 · Coronary heart disease
How do statins help prevent heart disease? [2 marks]
Answer:
They reduce blood cholesterol levels (1); which slows the build-up of fatty material in arteries (1).
Question 33 · Spec 4.2.2.4 · Heart valves
Compare biological and mechanical replacement heart valves. [2 marks]
Answer:
Mechanical valves last longer but need lifelong drugs to stop blood clots (1); biological valves (from animals) do not need these drugs but wear out sooner (1).
Question 34 · Spec 4.2.2.4 · Heart failure
Why might a patient be given an artificial heart? [1 mark]
Answer:
To keep them alive while waiting for a heart transplant, or to let the heart rest.
Question 35 · Spec 4.2.2.5 · Health issues
Define the term 'health'. [1 mark]
Answer:
A state of physical and mental well-being.
Question 36 · Spec 4.2.2.5 · Health issues
Give two examples of how diseases interact. [2 marks]
Answer:
Any two from: defects in the immune system make communicable disease more likely (1); viruses can trigger cancers (1); immune reactions can trigger allergies (1); severe physical ill health can lead to depression (1).
Question 37 · Spec 4.2.2.6 · Lifestyle
Give one risk factor for each: type 2 diabetes, lung disease, liver disease. [3 marks]
Answer:
Type 2 diabetes: obesity (1). Lung disease: smoking (1). Liver disease: alcohol (1).
Question 38 · Spec 4.2.2.6 · Lifestyle
Why is a correlation between smoking and lung cancer not proof of cause on its own? [1 mark]
Answer:
Other factors could be involved; a causal mechanism must be shown, such as carcinogens in tobacco smoke.
Question 39 · Spec 4.2.2.7 · Cancer
What is the difference between benign and malignant tumours? [2 marks]
Answer:
Benign tumours stay in one place, usually within a membrane (1); malignant tumours invade neighbouring tissues and spread in the blood to form secondary tumours (1).
Question 40 · Spec 4.2.3.1 · Plant tissues
State the function of the palisade mesophyll. [1 mark]
Answer:
To carry out photosynthesis; its cells are packed with chloroplasts.
Question 41 · Spec 4.2.3.1 · Plant tissues
State the function of the spongy mesophyll. [1 mark]
Answer:
Air spaces allow gases to diffuse in and out of cells.
Question 42 · Spec 4.2.3.1 · Plant tissues
State the function of guard cells. [1 mark]
Answer:
They open and close stomata to control gas exchange and water loss.
Question 43 · Spec 4.2.3.2 · Transpiration
Define transpiration. [1 mark]
Answer:
The loss of water vapour from the leaves, mainly through the stomata.
Question 44 · Spec 4.2.3.2 · Transpiration
State four factors that increase the rate of transpiration. [2 marks]
Answer:
Higher temperature and higher light intensity (1); increased air flow and lower humidity (1).
Question 45 · Spec 4.2.3.2 · Translocation
What is translocation? [2 marks]
Answer:
The movement of dissolved sugars from the leaves to the rest of the plant (1); through phloem tubes (1).
Question 46 · Spec 4.2.3.2 · Xylem and phloem
Compare xylem and phloem. [2 marks]
Answer:
Xylem carries water and mineral ions up from the roots, and is made of dead cells strengthened with lignin (1); phloem carries sugars both up and down, and is made of living cells with pores in the end walls (1).
Question 47 · Spec 4.2.3.2 · Transpiration
Describe how a potometer is used to measure transpiration rate. [2 marks]
Answer:
Record how far an air bubble moves along the capillary tube in a set time (1); this shows the volume of water taken up by the shoot (1).
Question 48 · Spec 4.2.3.2 · Transpiration
An air bubble moves 15 mm in 5 minutes. Calculate the rate of water uptake. [1 mark]
Answer:
15 ÷ 5 = 3 mm per minute.
Question 49 · Spec 4.2.3.2 · Stomata
Why are there more stomata on the lower surface of a leaf? [1 mark]
Answer:
It is cooler and shaded, so less water is lost by evaporation.
Question 50 · Spec 4.2.2.1 · Required practical 4
Describe the test for lipids and a positive result. [2 marks]
Answer:
Add a few drops of Sudan III stain (or shake with ethanol, then water) (1); a red-stained oily layer (or a cloudy white emulsion) shows lipids are present (1).

← 4.1 Cell biology 4.3 Infection and response →

Organisation

All 50 questions and answers

More AQA GCSE Biology topics

Cookies on Knowledge Noodles

Cookie settings