Lecture 01, 2

• What is metabolism?

  The sum of all chemical reactions
• What two processes does metabolism involve?

  Catabolism and anabolism
• How are reactions requiring energy coupled in metabolism?

  To those needing energy
• What are the sources of energy in metabolism?

  Carbohydrates, fats, and proteins
• What is the currency of energy in cells?

  ATP
• How is ATP produced?

  Directly and indirectly
• What are important cofactors in glycolysis?

  NAD+ and FAD

  
• What is the Embden-Meyerhof pathway?

  A pathway for glycolysis

  
• Where does glucose come from in glycolysis?

  Breakdown of dietary carbohydrates

  
• What is produced from the oxidation of 1 glucose in glycolysis?

  2 pyruvates, ATP, and NADH

  
• In which type of cells does glycolysis occur?

  In practically all organisms
• Where does glycolysis take place in eukaryotic cells?

  In the cytosol
• What are the three stages of glycolysis?

  1. Activation by phosphorylation
  2. Cleavage of 6 carbon molecules
  3. Oxidation and ATP formation

  
• What happens during the first stage of glycolysis activation?

  Phosphorylation traps glucose in the cell

  
• What is the first step of glycolysis activation?

  First phosphorylation

  
• What enzyme catalyses the first phosphorylation in glycolysis?

  Hexokinase

  
• What does isomerisation in glycolysis produce?

  Fructose-6-phosphate

  
• What enzyme catalyses the isomerisation step?

  Phosphoglucose isomerase
• What is produced from the second phosphorylation in glycolysis?

  Fructose-1,6-bisphosphate

  
• What enzyme catalyses the second phosphorylation?

  Phosphofructokinase (PFK)
• What happens during the cleavage stage of glycolysis?

  6 carbon molecules split into two 3 carbon sugars
• What enzyme catalyses the cleavage of glucose?

  Aldolase

  
• What are the products of the cleavage stage?

  Isomers of 3 carbon sugars
• What drives the interconversion of isomers during glycolysis?

  Consumption of GAP
• What enzyme catalyses the interconversion of isomers?

  Triose phosphate isomerase
• What occurs during the oxidation and ATP formation stage of glycolysis?

  Phosphorylation coupled to oxidation

  
• What enzyme catalyses the oxidation step in glycolysis?

  Glyceraldehyde-3-phosphate dehydrogenase

  
• What high-energy compound is produced in glycolysis?

  1,3-bisphosphoglycerate
• What is the net yield of ATP from glycolysis?

  2 ATP

  
• What are the key points about glycolysis?

  • Occurs in cytoplasm
  • Each step has a specific enzyme
  • 2 ATP used, 4 ATP formed
  • 2 NAD+ reduced to provide 3 ATP
  • Anaerobic process

  
• What regulates glycolysis?

  Hexokinase, phosphofructokinase, pyruvate kinase
• What inhibits phosphofructokinase?

  ATP, drop in pH, citrate
• What activates phosphofructokinase?

  AMP and fructose-2,6-bisphosphate
• What inhibits hexokinase?

  Glucose-6-phosphate

  
• What inhibits pyruvate kinase?

  ATP, alanine, phosphorylation
• What activates pyruvate kinase?

  Fructose-1,6-bisphosphate

  
• What determines the fate of pyruvate?

  Organism, organ, metabolic demands
• What is fermentation in relation to pyruvate?

  Conversion to ethanol in yeast
• What is the role of lactate in muscles during intense activity?

  Regenerates NAD+
• What enzyme catalyses the conversion of pyruvate to lactate?

  Lactate dehydrogenase