F.L.S. Lectures 10-11

• What is the primary reason we eat food?

  To power and maintain cell integrity
• What happens to complex polymers during digestion?

  They are broken down into monomers
• In what form is glucose stored in the body?

  As glycogen
• What type of linkages are found in glycogen?

  Alpha 1,4 and alpha 1,6 linkages
• Where is glycogen mainly concentrated in the body?

  Mainly in the liver
• What is the primary function of glycogen in the liver?

  To be released into the bloodstream
• What is the Fed State in metabolism?

  0-4 hours after eating
• What nutrients are absorbed by the gut during the Fed State?

  Glucose, amino acids, and fatty acids
• How does the liver respond to insulin during the Fed State?

  By converting glucose into glycogen
• What is lipogenesis?

  Conversion of glucose into triglycerides
• What do muscles do with glucose during the Fed State?

  Store it as glycogen or use it
• What is the role of adipose tissue during the Fed State?

  Store fatty acids and triglycerides
• What does the brain primarily rely on for energy?

  Glucose
• What inhibits PFK allosterically when there is plenty of food?

  ATP and citrate
• What can G-6P be switched to produce?

  Glycogen and pentoses
• What is required for fatty acid synthesis?

  Transport of acetyl units across membranes
• What activates acetyl-CoA carboxylase?

  Citrate and insulin
• What is the reaction for producing malonyl-CoA?

  Acetyl-CoA + HCO3- + ATP
• What happens during the Fasted State (4-12 hours)?

  The body mobilizes stored energy
• What does the liver do during the Fasted State?

  Breaks glycogen down into glucose
• What is gluconeogenesis?

  Conversion of non-carbohydrate precursors into glucose
• What does the brain use as an alternative fuel during fasting?

  Ketone bodies
• What happens to muscle glucose uptake during fasting?

  It reduces due to low insulin
• What is lipolysis?

  Breakdown of triglycerides into fatty acids
• What is the urea cycle's purpose?

  To convert ammonia into urea
• What is produced from the breakdown of pyruvate under anaerobic conditions?

  Lactate
• What is the net gain of ATP from glycolysis?

  2 ATP
• What is the role of pyruvate dehydrogenase?

  To convert pyruvate into acetyl-CoA
• What is produced during the Krebs cycle for each acetyl-CoA?

  3 NADH, 1 FADH2, 1 GTP
• What is the function of the electron transport chain?

  To transfer electrons and pump protons
• What does ATP synthase do?

  Converts ADP to ATP using proton flow
• What is the role of uncoupling protein 1 (UCP1)?

  Generates heat by allowing proton flow
• What are the main stages of cellular respiration?

  1. Glycolysis
  2. Krebs Cycle
  3. Electron Transport Chain
• What are the key components of the citric acid cycle?

  • Acetyl-CoA
  • Citrate
  • Oxaloacetate
  • Succinate
• What are the irreversible steps in gluconeogenesis?

  1. Bypass of Pyruvate Kinase
  2. Bypass of Phosphofructokinase-1 (PFK-1)
  3. Bypass of Hexokinase
• What are the three enzymatic components of pyruvate dehydrogenase?

  • E1: Pyruvate decarboxylase
  • E2: Dihydrolipoyl transacetylase
  • E3: Dihydrolipoyl dehydrogenase
• What are the products of glycolysis?

  • 2 Pyruvate
  • 2 NADH
  • 2 ATP
• What are the products of the Krebs cycle for each acetyl-CoA?

  • 3 NADH
  • 1 FADH2
  • 1 GTP
• What are the main functions of the liver during different metabolic states?

  • Fed State: Glycogen storage and lipogenesis
  • Fasted State: Glycogenolysis and gluconeogenesis
  • Starved State: Reduced gluconeogenesis and ketogenesis
• What are the roles of different tissues during the Fed State?

  • Gut: Absorbs nutrients
  • Liver: Stores glucose as glycogen
  • Muscles: Store glucose as glycogen
  • Adipose Tissue: Stores fatty acids
  • Brain: Uses glucose for energy