Respiratory substrate

• What is aerobic respiration?

  A process where glucose is broken down in the presence of oxygen
• What is the first step in aerobic respiration?

  Glycolysis
• What is produced during glycolysis?

  Pyruvate
• What happens to pyruvate after glycolysis?

  It is converted into acetyl CoA through the link reaction
• Where do the co-enzymes go after the Krebs cycle?

  To the cristae for oxidative phosphorylation
• What is the respiratory substrate of choice?

  Glucose
• What role does oxygen play in aerobic respiration?

  It acts as the last electron acceptor in the electron transport chain
• How is the respiratory quotient calculated?

  By measuring the amount of oxygen consumed and carbon dioxide produced
• What is the respiratory quotient for carbohydrates?


  1
• What happens when carbohydrates are not available as a respiratory substrate?

  Other substances like lipids and proteins can be utilized
• What is glycogen and how is it related to glucose?

  Glycogen is a polysaccharide that can be hydrolyzed into glucose
• How are lipids utilized as a respiratory substrate?

  They are hydrolyzed into glycerol and fatty acids
• What is the structure of a glycerol molecule?

  A three-carbon molecule
• What happens to fatty acid chains during respiration?

  They are broken down into acetyl groups
• What is the respiratory quotient for lipids?

  0.7
• If 25 molecules of oxygen are consumed and 18 molecules of carbon dioxide are produced, what is the respiratory quotient?

  0.72
• What does a respiratory quotient close to 0.7 indicate?

  That lipids are the respiratory substrate of choice
• What happens when there are no carbohydrates or lipids available?

  The body will utilize proteins as a respiratory substrate
• What is the respiratory quotient for proteins?

  0.9
• What occurs to proteins during respiration?

  They are hydrolyzed into amino acids and deaminated
• How can amino acids enter the Krebs cycle?

  They can be converted to pyruvate or acetyl CoA
• If the oxygen consumption is 0.6 and carbon dioxide produced is 0.54, what can be concluded?

  That protein stores are being utilized
• What does an RQ of 1 indicate about the respiratory substrate being used?

  That carbohydrates are the primary substrate
• What does an RQ below 0.7 indicate?

  That anaerobic respiration is occurring
• What happens when exercise intensity increases?

  Anaerobic respiration increases due to insufficient oxygen
• What is lactic acid and how does it affect the body?

  It is produced during anaerobic respiration and can lower blood pH
• How does the body respond to increased lactic acid levels?

  By increasing carbon dioxide levels to stabilize blood pH