12. Respiration
12.1 Respiration
Core
State the uses of energy in the body of humans: muscle contraction, protein synthesis, cell division, active transport, growth, the passage of nerve impulses and the maintenance of a constant body temperature
State that respiration involves the action of enzymes in cells
12.2 Aerobic respiration
Core
Define aerobic respiration as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy
State the word equation for aerobic respiration as glucose + oxygen → carbon dioxide + water
Investigate the uptake of oxygen by respiring organisms, such as arthropods and germinating seeds
Supplement
State the balanced chemical equation for aerobic respiration as C6H12O6 + 6O2 → 6CO2 + 6H2O
Investigate the effect of temperature on the rate of respiration of germinating seeds
12.3 Anaerobic respiration
Core
Define anaerobic respiration as the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen
State the word equations for anaerobic respiration in muscles during vigorous exercise (glucose → lactic acid) and in the microorganism yeast (glucose → alcohol + carbon dioxide)
State that anaerobic respiration releases much less energy per glucose molecule than aerobic respiration
Supplement
State the balanced chemical equation for anaerobic respiration in the microorganism yeast as C6H12O6 → 2C2H5OH + 2CO2
State that lactic acid builds up in muscles and blood during vigorous exercise causing an oxygen debt
Outline how the oxygen debt is removed during recovery, limited to:
– aerobic respiration of lactic acid in the liver
– continuation, after exercise, of fast heart rate to transport lactic acid in blood from muscles to the liver
– continuation, after exercise, of deeper breathing supplying oxygen for aerobic respiration of lactic acid