GCSE Biology (OCR A)

Topic Summaries

Photosynthesis and respiration

Metabolism and response to exercise

  • Metabolism is the sum of all the reactions in a cell or the body. This includes:
    • Respiration and conversion of glucose to starch, glycogen, and cellulose.
    • The formation of lipid molecules from a molecule of glycerol and three molecules of fatty acids.
    • The use of glucose and nitrate ions to form the amino acids for protein synthesis.
    • Digestion (breakdown of carbohydrates, proteins, and lipids)
    • Breakdown of excess proteins to form urea for excretion.
  • The energy released by cellular respiration is used by the organism for the continual enzyme-controlled processes of metabolism to synthesise new molecules.
  • During exercise, the human body reacts to the increased demand for energy.
  • Heart rate, breathing rate and breath volume increase to supply the muscles with more oxygenated blood so they can carry out maximum aerobic respiration to release energy for movement.

Unlock Metabolism and response to exercise

Sign up to unlock the rest of this topic — plus every other topic, video, flashcard set and eBook guide in your SnapRevise+ subscription.

Cancel anytime — instant access the moment you sign up.