cell resp

Cellular Respiration

  • Organisms metabolize food to produce energy for growth, maintenance, and reproduction.
  • Cellular respiration converts glucose to energy (ATP) in the presence of oxygen.
  • Waste product: carbon dioxide (CO₂).
  • Glucose is metabolized in two stages: glycolysis and respiration.

Glycolysis and Aerobic Respiration

  • Glycolysis: glucose breaks down to pyruvate, yielding small amounts of ATP.
  • Aerobic Respiration: occurs in mitochondria (eukaryotes) or cell membrane (prokaryotes).
  • Equation for aerobic respiration: C<em>6H</em>12O<em>6+6O</em>2→6CO<em>2+6H</em>2O+36ATPC<em>6H</em>{12}O<em>6 + 6O</em>2 \rightarrow 6CO<em>2 + 6H</em>2O + 36 ATP.
  • Respiration rate can be measured by changes in glucose, oxygen, or CO₂ levels.

Fermentation

  • In absence of oxygen, pyruvate converts to lactate or ethanol and CO₂ through fermentation.

Gas Laws and Measurement

  • Reactions with potassium hydroxide (KOH) sequester CO₂, allowing measurement of O₂ consumption via respirometer.
  • Combined gas law: PV=nRTPV = nRT. Conditions:
    • Volume proportional to the number of gas molecules (constant T, P).
    • Pressure changes with number of molecules (constant T, V).
    • Volume inversely proportional to pressure (constant n, T).

Experimental Procedure

  • Demonstration involves measuring oxygen consumption using respirometers with germinating peas and acrylic beads.
  • Steps include setting up water baths, calibrating respirometers, and taking volume measurements over time.

Assessments

  • Key questions include interpreting respiration data, identifying controls, and factors affecting experimental outcomes.