Respiration flashcards

Topic 10: Respiration

Respiration (definition)

The chemical reactions in all living cells that release energy from glucose.

Aerobic and anaerobic respiration (definitions)

Aerobic: the release of a relatively large amount of energy by the breakdown of glucose in the presence of oxygen. Anaerobic: the release of a relatively small amount of energy by the breakdown of glucose without using oxygen.

Aerobic respiration: word and balanced equations

glucose + oxygen → carbon dioxide + water C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Anaerobic respiration in humans and in yeast (word equations)

Humans (muscles): glucose → lactic acid. Yeast: glucose → ethanol + carbon dioxide.

Seven uses of energy released in respiration

Muscle contraction, protein synthesis, cell division, active transport, growth, passage of electrical impulses along neurones, maintenance of a constant body temperature.

Why does yeast release almost no gas at 60 °C?

The enzymes that control respiration are denatured, so the reactions stop.

Why does lactic acid build up during vigorous exercise?

Oxygen cannot be supplied fast enough for aerobic respiration alone, so muscles also respire anaerobically and lactic acid builds up in the muscles and blood.

Oxygen debt (EPOC)

The extra oxygen needed after vigorous exercise to break down the lactic acid that built up. EPOC: Excess Post-exercise Oxygen Consumption.

How the oxygen debt is removed

A fast heart rate continues, transporting lactic acid from the muscles to the liver. Deeper and faster breathing continues, supplying oxygen for its breakdown in the liver.

Cells (where respiration happens)

Aerobic respiration happens in the mitochondria; muscle cells have many of them.