Cellular Respiration Notes

Uses of Glucose

• To produce fat or oil for storage (in seeds).
• To produce cellulose to strengthen cell walls.
• Combined with nitrates (absorbed from the soil) to form amino acids which produce proteins.

Respiration (4.2)

• Respiration occurs in every cell, transferring energy from glucose for living processes.
• All living things undergo respiration.
• It is exothermic.
• It can take place aerobically (with oxygen) or anaerobically (without oxygen).

Response to Exercise (4.2.2)

• During exercise, more energy is needed for muscle contraction.
• Respiration has to occur faster.
• More oxygen needs to be supplied to cells, and more $CO_2$ removed.
• This is done by:
  • Heart rate increasing
  • Breathing rate increasing
  • Breath volume increasing

Aerobic Respiration

• Uses oxygen; yields the most energy.
• Most reactions occur in the mitochondria.
• Equation: $C<em>6H</em>{12}O<em>6 + O</em>2 \longrightarrow CO<em>2 + H</em>2O$
  • $C<em>6H</em>{12}O_6$ = glucose
  • $O_2$ = oxygen
  • $CO_2$ = carbon dioxide
  • $H_2O$ = water

Anaerobic Respiration

• Occurs when there is not enough oxygen; yields less energy than aerobic respiration.
• Used as a last resort (e.g., during a sprint).
• Oxidation of glucose is incomplete.
• In animals: Glucose ($C<em>6H</em>{12}O_6$) → Lactic acid
• In plant and yeast cells (fermentation): Glucose ($C<em>6H</em>{12}O<em>6$) → Ethanol + Carbon dioxide ($CO</em>2$)
  • Used to make bread and alcoholic drinks.