Respiration

• Cellular respiration


  An exothermic reaction that occurs continuously in the mitochondria of living cells to supply the cells with energy
• Cellular respiration


  • The energy released during respiration is needed for all living processes, including:
  • Chemical reactions to build larger molecules, for example, making proteins from amino acids
  • Muscle contraction for movement
  • Keeping warm
• Aerobic respiration


  Respiration that uses oxygen
• Anaerobic respiration


  Respiration that occurs without oxygen
• Aerobic respiration


  • Complete oxidation of glucose, large amount of energy is released
• Anaerobic respiration


  • Incomplete oxidation of glucose, much less energy is released than in aerobic respiration
• Aerobic respiration


  glucose + oxygen → carbon dioxide + water
• Anaerobic respiration in muscles

  glucose → lactic acid
• Anaerobic respiration in plant and yeast cells

  glucose → ethanol + carbon dioxide
• Fermentation


  Anaerobic respiration in yeast cells
• Fermentation


  • The products are important in the manufacturing of bread and alcoholic drinks
• Parts of a typical plant cell

  • Cell wall
  • Chloroplast
  • Cytoplasm
  • Nucleus
  • Mitochondrion
  • Cell membrane
• Enzymes for anaerobic respiration are located in the cytoplasm
• Enzymes for aerobic respiration are located in the mitochondria
• The nucleus holds the genetic code for enzymes involved in respiration
• The cell membrane allows gases and water to pass freely into and out of the cell, and controls the passage of other molecules
• During exercise


  Breathing rate, breath volume, and heart rate all increase to supply the muscles with more oxygenated blood
• If insufficient oxygen is supplied

  Anaerobic respiration takes place instead, leading to the build-up of lactic acid
• During long periods of vigorous exercise

  Muscles become fatigued and stop contracting efficiently
• After exercise


  Oxygen debt is the amount of oxygen needed to react with the lactic acid to remove it from cells
• Removal of lactic acid


  Lactic acid in the muscles is transported to the liver in the blood, where it is converted back to glucose
• Metabolism


  The sum of all the reactions in a cell or the body
• Metabolic processes


  • Synthesis and breakdown of carbohydrates, proteins, and lipids
• The energy released by respiration in cells is used for the continual enzyme-controlled processes of metabolism that produce new molecules
• A question on respiration could be easily linked to one on enzyme action and breakdown of carbohydrates, proteins, or lipids
• Questions in the exam can link a few topics together within one question
• Cellspiration


  An exothermic reaction that occurs continuously in the mitochondria of living cells to release energy from glucose
• What organisms need energy for

  • Chemical reactions to build larger molecules
  • Muscle contraction for movement
  • Keeping warm
• Aerobic respiration


  Uses oxygen
• Anaerobic respiration


  Does not use oxygen
• Aerobic respiration


  Glucose + Oxygen -> Carbon dioxide + Water
• Anaerobic respiration in muscles

  Glucose -> Lactic acid
• Aerobic respiration releases more energy than anaerobic respiration
• Anaerobic respiration in plant and yeast cells

  Glucose -> Ethanol + Carbon dioxide
• During exercise


  Heart rate, breathing rate, and breath volume increase to supply muscles with more oxygenated blood
• Lactic acid


  Substance that builds up in muscles during anaerobic respiration
• Muscles become fatigued and stop contracting efficiently during long periods of activity
• Oxygen debt


  The amount of oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from cells
• Removing lactic acid from the body


  Lactic acid in muscles -> Blood transports to liver -> Lactic acid converted back to glucose
• Metabolism


  The sum of all the reactions in a cell or the body