cellular respiration

• What are the two ways glucose can be broken down?


  Fermentation and Cellular Respiration
• What type of pathways are fermentation and cellular respiration?


  Both are catabolic pathways
• What is the chemical equation for cellular respiration?


  C$_6$H$_{12}$O$_6$ + 6O$_2$ ---> 6CO$_2$ + 6H$_2$O + Energy (ATP + heat)
• What happens to hydrogen atoms during glucose breakdown?


  There is a loss of hydrogen atoms from glucose and a gain of hydrogen atoms in energy
• What does OILRIG stand for?


  Oxidation is losing electrons, Reduction is gaining electrons
• How does glucose give off energy?


  Glucose gives off energy as it is oxidized
• What is the role of sodium and chloride in oxidation and reduction?


  Sodium is oxidized by losing an electron, while chloride is reduced by gaining an electron
• What are electron donors and acceptors in redox reactions?


  Electron donors are reducing agents, and electron acceptors are oxidizing agents
• What are the electron carrier molecules involved in cellular respiration?

  NAD⁺ and FAD⁺
• What is the function of electron transport chains?


  They shuttle electrons that release energy used to make ATP
• How does the electron route in cellular respiration proceed?

  Food → NADH → electron transport chain → oxygen
• What happens to hydrogen during reduction and oxidation?


  Gain or loss of electrons is often in the form of hydrogen
• What is the role of NAD⁺ in cellular respiration?


  NAD⁺ acts as the energy carrier and removes electrons from food
• What is produced when NAD⁺ picks up electrons?


  It is reduced to NADH
• What are the stages of cellular respiration?

  Glycolysis, Krebs Cycle, and Electron Transport Chain

  
• Where does glycolysis occur?


  In the cytoplasm
• Where do the Krebs Cycle and Electron Transport Chain take place?


  In the mitochondria
• What is the structure of mitochondria?


  • Smooth outer membrane
  • Folded inner membrane (Cristae)
  • Space inside cristae (Matrix)
• What are the three metabolic stages of respiration?

  1. Glycolysis: Degrades glucose into pyruvate
  2. Krebs Cycle: Converts pyruvate into carbon dioxide
  3. Electron Transport Chain: Electrons passed to oxygen
• What is the net energy yield of glycolysis per glucose molecule?


  2 ATP plus 2 NADH
• What are the products of glycolysis besides pyruvate?


  2 NADH, 2 ATP, and 2 H₂O
• What happens to pyruvate after glycolysis?


  It is oxidized to Acetyl CoA and a CO₂ is removed
• What is the energy investment phase of glycolysis?


  It is when the cell uses ATP to phosphorylate fuel
• What is the energy payoff phase of glycolysis?


  ATP is produced by substrate-level phosphorylation and NAD⁺ is reduced to NADH
• How many ATP are used in the energy investment phase of glycolysis?


  2 ATP
• How many ATP are produced in glycolysis?


  4 ATP
• What is the net ATP yield from glycolysis?


  2 ATP
• What happens during the steps of glycolysis?


  A glucose molecule is energized, split, and produces pyruvate
• What are the steps of glycolysis in detail?


  1. Glucose is energized using ATP
  2. A six-carbon intermediate splits into two three-carbon molecules
  3. A redox reaction generates NADH
  4. Two ATP and two molecules of pyruvic acid are produced

  
• What must happen before the citric acid cycle can begin?


  Pyruvate must be converted to acetyl CoA
• How many times does the Krebs Cycle turn per glucose molecule?


  Twice
• What are the products of one turn of the Krebs Cycle?


  3 NADH, 1 FADH₂, and 1 ATP
• What are the total products of the Krebs Cycle for each glucose molecule?


  6 NADH, 2 FADH₂, 4 CO₂, and 2 ATP
• What happens to carbon atoms during the Krebs Cycle?


  2 carbon atoms enter and 2 exit as carbon dioxide
• What is produced when molecular oxygen is present during the Krebs Cycle?


  Each pyruvate is converted into acetyl CoA and CO₂ is released
• What are the steps of the Krebs Cycle?


  1. Acetyl CoA adds its two-carbon acetyl group to oxaloacetate, producing citrate
  2. Citrate is converted to isocitrate
  3. Isocitrate loses a CO₂ molecule and reduces NAD⁺ to NADH
  4. Another CO₂ is lost, reducing NAD⁺ to NADH
  5. CoA is displaced, forming ATP
• What is the role of GTP in the Krebs Cycle?


  GTP is formed from GDP and phosphate, which can be converted to ATP
• What is the significance of substrate-level phosphorylation in the Krebs Cycle?


  It produces ATP directly from a substrate
• What is the final electron acceptor in the electron transport chain?


  Oxygen
• What is the main purpose of the electron transport chain?


  To produce ATP through oxidative phosphorylation