Respiration

• What is the overall equation for aerobic respiration?


  Glucose + Oxygen --> Carbon dioxide + Water + ATP
• What is glucose used for in cellular respiration?


  Glucose is used in glycolysis
• What role does oxygen play in aerobic respiration?

  Oxygen is used in the electron transport chain (ETC)
• Where is carbon dioxide produced during aerobic respiration?


  Carbon dioxide is produced in the link reaction and Krebs cycle
• Where is water produced in aerobic respiration?


  Water is produced in the electron transport chain (ETC)
• How is ATP produced during aerobic respiration?

  ATP is produced in glycolysis and the Krebs cycle through substrate level phosphorylation, and also during oxidative phosphorylation
• What are the main steps of aerobic respiration?


  • Glycolysis
  • Link reaction
  • Krebs cycle
  • Oxidative phosphorylation (ETC + Chemiosmosis)
• What is the relationship between ADP and ATP?

  ADP + Pi <--> ATP + Water
• How many phosphates does ADP have?


  ADP has two phosphates
• What is Pi in the context of ATP?

  Pi is an inorganic phosphate
• What type of reaction occurs when ATP is formed from ADP and Pi?

  It is a condensation reaction
• What components do both ADP and ATP share?

  Both ADP and ATP have a ribose sugar and adenine
• How many phosphates does ATP have?

  ATP has three phosphates
• What is oxidation in terms of electron transfer?

  Oxidation is the loss of electrons
• What is reduction in terms of electron transfer?


  Reduction is the gain of electrons
• What are the characteristics of oxidation and reduction?

  • Oxidation:
  • Loss of electrons
  • Loss of hydrogen
  • Gain of oxygen
  • Reduction:
  • Gain of electrons
  • Gain of hydrogen
  • Loss of oxygen
• What are the two hydrogen carriers in respiration?

  • NAD (which becomes NADH)
  • FAD (which becomes FADH2)
• Where do different stages of aerobic respiration occur in the mitochondria?


  • Cytoplasm: Glycolysis
  • Matrix: Link reaction and Krebs cycle
  • Inner membrane: Oxidative phosphorylation
  • Cristae: ATP synthase, chemiosmosis
• What is the function of ATP synthase?

  ATP synthase produces ATP
• What type of ribosomes do mitochondria have?

  Mitochondria have 70s ribosomes
• What is the structure of mitochondrial DNA?


  Mitochondria have a naked loop of circular DNA
• What is the intermembrane space in mitochondria?


  The intermembrane space is where protons build up
• What are the steps of glycolysis?

  1. Phosphorylation: glucose to hexose biphosphate (uses 2 ATP)
  2. Lysis: hexose biphosphate to two triose phosphate (3C)
  3. Oxidation + ATP formation: two triose phosphate (3C) to two pyruvate (3C), producing 2 NADH and 4 ATP
• What is the summary of glycolysis?


  • Occurs in the cytoplasm
  • Glucose to 2 pyruvate
  • 2 NAD to 2 reduced NAD
  • Net 2 ATP formed through substrate level phosphorylation
  • Does not require oxygen
• What happens to pyruvate in the link reaction?


  Pyruvate enters the mitochondrion and is converted to acetyl CoA
• What occurs during the link reaction?

  Pyruvate (3C) is converted to acetyl CoA (2C), with one carbon dioxide and one hydrogen removed
• What is the summary of the link reaction?

  • Occurs in the matrix
  • 2 pyruvates to 2 acetyl CoA
  • 2 NAD to 2 NADH
  • 2 carbon dioxide produced
• What is produced during the Krebs cycle?


  The Krebs cycle produces NADH, FADH2, carbon dioxide, and ATP
• What are the steps of the Krebs cycle?

  1. Acetyl CoA (2C) combines with oxaloacetate (4C) to form citrate (6C)
  2. Citrate goes to 5C, producing carbon dioxide and NADH
  3. 5C goes to 4C, producing carbon dioxide and NADH
  4. 4C to 4C, ATP formation occurs through substrate level phosphorylation
  5. 4C goes to 4C, FAD becomes FADH2
  6. 4C goes to oxaloacetate, NAD goes to NADH
• What is the summary of the Krebs cycle?

  • Occurs in the matrix
  • 6 NAD to 6 NADH
  • 2 FAD to 2 FADH2
  • Produces 4 carbon dioxide
  • Produces 2 ATP
• What does it mean when NAD or FAD is reduced?

  When NAD or FAD is reduced, something else is oxidized
• What is decarboxylation?


  Decarboxylation is when a carbon is lost
• What are the steps of oxidative phosphorylation?

  1. Electrons flow through a series of carriers down an energy gradient in the ETC
  2. NADH and FADH2 release electrons, which are transferred between carriers
  3. Protons are pumped from the matrix across the inner membrane to establish a proton gradient
  4. At the final pump, electrons react with protons and oxygen to form water
  5. Oxygen is the final electron acceptor
• What is chemiosmosis?

  • Protons are pumped across the inner membrane into the intermembrane space
  • A proton gradient is established
  • Protons diffuse back through the inner membrane to the matrix through ATP synthase
  • ATP production is coupled with the flow of protons
• What is the role of oxygen in aerobic respiration?

  Oxygen is the final electron acceptor at the end of the ETC
• How does oxygen prevent the buildup of lactic acid?

  Oxygen is highly electronegative and acts as the final electron acceptor
• What are the functions of oxygen in aerobic respiration?


  • Final electron acceptor at the end of the ETC
  • Accepts protons to produce water
  • Maintains proton gradient
  • Allows NAD and FAD to be regenerated
  • Allows complete oxidation of glucose
• How do lipids and carbohydrates compare as respiratory substrates?

  • As hydrogen content increases, energy content increases
  • Lipids have more hydrogen than carbohydrates
  • Energy content:
  • Carbs: 15.8
  • Proteins: 17
  • Lipids: 39.4
• What is anaerobic respiration in humans?

  • Glycolysis takes glucose and produces 2 pyruvate, net 2 ATP, and produces NADH
  • Fermentation converts pyruvate to lactate, oxidizing NADH to NAD
• What is anaerobic respiration in yeast?

  • Glycolysis takes glucose and produces 2 pyruvate along with NADH
  • Fermentation produces carbon dioxide and ethanal
  • Ethanal becomes ethanol, oxidizing NADH to NAD