Respiration

Learning objectives

Describe respiration as the chemical reactions in cells that break down nutrient molecules to release energy for metabolism, state that it involves enzymes, and list the uses of energy in living organisms (muscle contraction, protein synthesis, cell division, active transport, growth, the passage of nerve impulses and keeping body temperature constant)

Describe aerobic respiration as respiration that uses oxygen, state its word equation, and state the balanced chemical equation at Extended

Investigate and describe the effect of temperature on the rate of respiration in yeast

Describe anaerobic respiration as the release of energy without oxygen, state the word equations for anaerobic respiration in yeast (ethanol and carbon dioxide) and in muscles during vigorous exercise (lactic acid), state the balanced equation for yeast (C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂) at Extended, and state that it releases much less energy per glucose molecule than aerobic respiration

Outline how lactic acid builds up in muscles and blood during vigorous exercise, causing an oxygen debt, and how the debt is removed afterwards by aerobic respiration of lactic acid in the liver, supported by a continued fast heart rate and deeper breathing (Extended)