Exchange and Transport in Animals

What Exchange and Transport in Animals covers

Exchange and Transport in Animals is examined in Paper 2, Biology 2. It covers why multicellular organisms need exchange surfaces and transport systems, alveoli and gas exchange, the blood, arteries, veins and capillaries, the heart and the double circulation, aerobic and anaerobic respiration, investigating the rate of respiration with a respirometer, and cardiac output.

The 9 subtopics

Each one has its own page.

• Why multicellular organisms need exchange surfacesThe oxygen, carbon dioxide, water, glucose, mineral ions and urea that must be transported in an organism, calculating surface area to volume ratios of cubes, and why single-celled organisms and flatworms rely on diffusion while large animals need exchange surfaces and transport systems.Open →
• Alveoli and gas exchangeAlveoli as the site of gas exchange, how their number, one-cell-thick walls, capillary network, moist lining and ventilation keep the diffusion of oxygen and carbon dioxide fast, and the two cell layers oxygen crosses into the blood.Open →
• The blood and its componentsRed blood cells, haemoglobin and oxyhaemoglobin, their biconcave shape and lack of a nucleus, phagocytes and lymphocytes, plasma and what it carries, platelets and clotting, estimating cell numbers per cubic millimetre, and pie chart angles and percentages for the parts of a blood sample.Open →
• Arteries, veins and capillariesArteries, veins and capillaries and the direction each carries blood, and how the thick elastic walls and narrow lumen of arteries, the valves and wide lumen of veins, and the thin walls and dense networks of capillaries suit their functions.Open →
• The heart and the circulatory systemThe four chambers of the heart and why their walls differ in thickness, the vena cava, pulmonary artery, pulmonary vein and aorta, valves, the route from the right atrium to the lungs, the double circulation, and the coronary arteries that supply the heart muscle.Open →
• Cellular respiration as an exothermic reactionWhat happens in cellular respiration, why it is exothermic and continuous in every living cell, how its energy is used for muscle contraction, building large molecules, active transport and keeping mammals warm, and the two types of respiration.Open →
• Aerobic and anaerobic respiration comparedThe word and balanced symbol equations for aerobic respiration in mitochondria, anaerobic respiration producing lactic acid in muscles and ethanol and carbon dioxide in yeast and plants, fermentation, why anaerobic respiration releases less energy, and why sprinters respire anaerobically and what happens to lactic acid.Open →
• Investigating the rate of respirationUsing a respirometer with germinating peas or woodlice, soda lime and a glass bead control, the variables, airtightness, settling time, errors and safety, calculating means, ranges and uncertainty, anomalous results and range bars, and treating small animals ethically.Open →
• Cardiac output, stroke volume and heart rateStroke volume, heart rate and cardiac output and the equation linking them, calculating each from the other two, working out heart rate from a pulse count, converting to cubic decimetres, and why cardiac output rises during exercise.Open →

What you need to know

Answer each one before you reveal it.

Take Exchange and Transport in Animals further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Artery vs Vein

  Artery: thick-walled vessel carrying high-pressure blood away from the heart. Vein: wide-lumen vessel with valves returning low-pressure blood to the heart.

• Aerobic respiration vs Anaerobic respiration

  Aerobic respiration: breakdown of glucose with oxygen to carbon dioxide and water. Anaerobic respiration: partial breakdown of glucose without oxygen to lactic acid.

• Stroke volume vs Cardiac output

  Stroke volume: amount of blood a ventricle pumps out in one beat. Cardiac output: amount of blood a ventricle pumps out in one minute.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Name the gas that must be transported from the lungs to respiring cells.

   Model answer

   Oxygen is transported from the lungs to respiring cells.

2. 2

   Name the waste gas that must be carried away from respiring cells.

   Model answer

   Carbon dioxide is carried away from respiring cells.

3. 3

   State why water must be moved around an organism.

   Model answer

   Every cell needs water as the solvent in which its chemical reactions take place.

4. 4

   Name the dissolved food molecule that is carried to cells for respiration.

   Model answer

   Glucose is carried in solution to cells for respiration.

5. 5

   State where dissolved food molecules pass into the blood.

   Model answer

   Dissolved food molecules are absorbed into the blood through the wall of the small intestine.

6. 6

   State why mineral ions must be transported to cells.

   Model answer

   Cells need mineral ions to build substances such as haemoglobin and to keep their chemical processes working.

What is inside Levo

Six ways to work the same material.

Exchange and Transport in Animals revision questions

What does Exchange and Transport in Animals cover in Edexcel GCSE Combined Science Biology?

9 subtopics: why multicellular organisms need exchange surfaces, alveoli and gas exchange, the blood and its components, arteries, veins and capillaries, the heart and the circulatory system, cellular respiration as an exothermic reaction, aerobic and anaerobic respiration compared, investigating the rate of respiration and cardiac output, stroke volume and heart rate. Each one has its own page with questions and model answers.

How is Exchange and Transport in Animals organised?

By the Edexcel 1SC0 specification, subtopic by subtopic, so it matches the order you are taught it in.