4.2-respiration

• What is aerobic respiration?

  An exothermic reaction releasing energy
• Where does aerobic respiration take place?

  In the mitochondria
• What is the word equation for aerobic respiration?

  Glucose + oxygen → carbon dioxide + water
• What is the symbol equation for aerobic respiration?

  C6H12O6 + 6O2 → 6CO2 + 6H2O
• Why do organisms require the energy released by respiration?

  For synthesis, muscle contraction, and transport
• What is anaerobic respiration?

  An exothermic reaction without oxygen
• Why is anaerobic respiration less efficient than aerobic respiration?

  Glucose is not completely broken down
• What is the equation for anaerobic respiration?

  Glucose → lactic acid
• Why can anaerobic respiration lead to muscle fatigue?

  Lactic acid builds up in muscles
• What is aerobic respiration?

  An exothermic reaction in which glucose reacts with oxygen to release energy which can be used by cells
• What are the equations for aerobic respiration (word and symbol)?

  Glucose + oxygen → carbon dioxide + water (+energy), C6H12O6 + 6O2 → 6CO2 + 6H2O (+energy)
• Why do organisms require the energy released by respiration?

  For synthesis of larger molecules, muscle contraction, maintenance of body temperature, and active transport
• What is anaerobic respiration?

  An exothermic reaction in which glucose is broken down to release energy in the absence of oxygen
• Why is anaerobic respiration less efficient than aerobic respiration?

  Glucose is not completely broken down, so less energy is transferred
• What is the equation for anaerobic respiration?

  Glucose → lactic acid (+energy)
• Why can anaerobic respiration lead to muscle fatigue?

  Lactic acid (product of anaerobic respiration) builds up in muscles, preventing efficient contraction
• What is an oxygen debt?

  The amount of oxygen needed to convert lactic acid into back into glucose after anaerobic respiration
• What is the equation for fermentation?

  Glucose → ethanol + carbon dioxide (+energy)
• What is fermentation?

  A type of anaerobic respiration that occurs in yeast cells
• Why is the fermentation reaction important?

  It is used in the production of bread and alcoholic drinks
• What are the differences between aerobic and anaerobic respiration?

  Aerobic requires oxygen, produces CO2 and water, and transfers a greater amount of energy; anaerobic does not require oxygen, produces lactic acid or ethanol + CO2, and transfers less energy
• What changes take place when muscular activity increases in the body?

  Heart rate increases and arteries dilate to increase flow of oxygenated blood, breathing rate and depth increase to increase gaseous exchange, and stored glycogen is converted back into glucose
• How do muscles store glucose?

  As glycogen
• How is lactic acid transported away from the muscles?

  Blood flow through the muscles transports lactic acid to the liver, where it is oxidised back to glucose
• What is metabolism?

  The sum of all the reactions that take place in a cell or an organism
• Give examples of metabolic reactions

  Glucose into starch/glycogen/cellulose, glycerol and fatty acids into lipids, glucose and nitrate ions into amino acids, photosynthesis, respiration, breakdown of excess proteins into urea
• How do cells use the energy transferred by respiration?

  To continuously carry out enzyme-controlled processes which lead to the synthesis of new molecules
• What are the key differences between aerobic and anaerobic respiration?

  • Aerobic requires oxygen, anaerobic does not
  • Aerobic produces CO2 and water, anaerobic produces lactic acid or ethanol + CO2
  • Aerobic transfers a greater amount of energy
• How does the body respond to increased muscular activity?

  • Heart rate and blood flow increase to deliver more oxygenated blood
  • Breathing rate and depth increase to enhance gaseous exchange
  • Stored glycogen is converted back into glucose
• How is lactic acid transported and processed after anaerobic respiration?

  • Lactic acid is transported in the blood to the liver
  • In the liver, lactic acid is oxidized back into glucose
• What is metabolism and give examples of metabolic reactions?

  Metabolism is the sum of all chemical reactions in a cell or organism, including:

  • Conversion of glucose into starch, glycogen, or cellulose
  • Synthesis of lipids from glycerol and fatty acids
  • Formation of amino acids from glucose and nitrate ions
  • Photosynthesis, respiration, protein breakdown