Finals 1

• Digestion


  Biochemical process by which food molecules, through hydrolysis, are broken down into simpler chemical units that can be used by cells for their metabolic needs
• Glycolysis


  Metabolic pathway by which glucose (a C6 molecule) is converted into two molecules of pyruvate (a C3 molecule), chemical energy in the form of ATP is produced, and NADH-reduced coenzymes are produced
• Lysis

  Breakdown
• Glyco

  Glucose
• The conversion of glucose to pyruvate is an oxidation process in which no molecular oxygen is utilized
• Oxidizing agent


  Coenzyme reduced nicotinamide adenine dinucleotide [glycolysis process]
• Metabolic pathways

  • Anaerobic pathways
  • Aerobic pathways
• Anaerobic pathways


  Metabolic pathways in which molecular oxygen is not a participant
• Glycolysis is an anaerobic pathway
• Aerobic pathways


  Pathways that require molecular oxygen
• Glycolysis

  1. 10-step process

  2. Each step catalyzed by an enzyme
• Stages of glycolysis

  • 6-carbon stage [1-3]
  • 3-carbon stage [4-10]
• All of the enzymes needed for glycolysis are present in the cell cytosol which is where the glycolysis takes place
• 1. carbon stage of glycolysis

  Energy-consuming or energy-investment stage
• In the 6-carbon stage, 2 molecules of ATP are consumed
• Intermediates of the 6-carbon stage

  Glucose or fructose derivatives in which phosphate groups are present
• 1. carbon stage of glycolysis

  Energy-generating stage
• In the 3-carbon stage, 4 molecules of ATP are synthesized, as well as NADH reduced coenzymes
• Step 1: Phosphorylation

  Formation of Glucose 6-Phosphate
• Glucokinase or hexokinase


  Enzymes responsible for phosphorylating glucose to glucose 6-phosphate
• This reaction is the first irreversible reaction of glycolysis that consumes ATP
• Step 2: Isomerization

  Glucose 6-phosphate is isomerized into Fructose 6-Phosphate
• Phosphoglucoisomerase


  Enzyme that catalyzes the isomerization
• Isomers


  Compounds that have the same chemical formula, but different structures
• Step 3: Phosphorylation

  Formation of Fructose 1,6-Bisphosphate
• Phosphofructokinase


  Enzyme that catalyzes the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate
• This is the second irreversible reaction that consumes ATP
• 1. carbon stage of glycolysis


  Also called the energy-generating stage
• There are 4 molecules of ATP synthesized, as well as 2 NADH coenzymes
• Step 4: Cleavage

  Formation of Two Triose Phosphates
• Aldolase


  Enzyme responsible for cleaving fructose 1,6-bisphosphate into two triose phosphates
• The two trioses produced are not identical - one is dihydroxyacetone phosphate and the other is glyceraldehyde 3-phosphate
• Step 5: Isomerization of glyceraldehyde 3-phosphate


  Conversion of dihydroxyacetone phosphate into glyceraldehyde 3-phosphate
• Triosephosphate isomerase


  Enzyme responsible for the isomerization
• Step 6: Oxidation and phosphorylation

  Formation of 1,3-Bisphosphoglycerate
• Glyceraldehyde 3-phosphate dehydrogenase


  Enzyme that oxidizes glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate
• Oxidoreductases


  Important in carrying out oxidation-reduction reactions
• High-energy phosphate group

  Phosphate group attached to a carbon atom that is also participating in a carbon-carbon or carbon-oxygen double bond
• Step 7: Phosphorylation of ADP

  Formation of 3-phosphoglycerate
• Phosphoglycerokinase


  Enzyme that transfers the phosphate group from 1,3-bisphosphoglycerate to ADP, producing 2 ATP