Biochem Finals

• Digestion


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

  
• Glycolysis


  Metabolic pathway by which glucose is converted into two molecules of pyruvate, producing chemical energy in the form of ATP and NADH-reduced coenzymes

  
• Anaerobic pathways


  • Metabolic pathways in which molecular oxygen is not a participant
• Aerobic pathways


  • Pathways that require molecular oxygen
• Six-Carbon Stage of Glycolysis (Steps 1–3)

  1. Step 1: Phosphorylation - Formation of Glucose 6-Phosphate

  2. Step 2: Isomerization - Formation of Fructose 6-Phosphate

  3. Step 3: Phosphorylation - Formation of Fructose 1,6-Bisphosphate

  
• Three-Carbon Stage of Glycolysis (Steps 4–10)

  1. Step 4: Cleavage - Formation of Two Triose Phosphates

  2. Isomerization - Formation of Glyceraldehyde 3-Phosphate

  3. Step 6: Oxidation and Phosphorylation - Formation of 1,3 Bisphosphoglycerate

  4. Step 7: Phosphorylation of ADP - Formation of 3-Phosphoglycerate

  5. Step 8: Isomerization - Formation of 2-Phosphoglycerate

  6. Step 9: Dehydration - Formation of Phosphoenolpyruvate

  7. Step 10: Phosphorylation of ADP - Formation of Pyruvate

  
• Substrate-level phosphorylation


  Biochemical process by which a high energy phosphate group from an intermediate compound (substrate) is directly transferred to ADP to produce ATP

  
• Lactate Fermentation


  Enzymatic anaerobic reduction of pyruvate to lactate
• Lactate fermentation is the sole purpose of converting NADH to NAD without oxygen
• Ethanol Fermentation


  Enzymatic anaerobic conversion of pyruvate to ethanol and carbon dioxide
• Glycogenesis


  Metabolic pathway by which glycogen is synthesized from glucose 6-phosphate

  
• Glycogenolysis


  Metabolic pathway by which glucose 6-phosphate is produced from glycogen

  
• Gluconeogenesis


  Metabolic pathway by which glucose is synthesized from noncarbohydrate materials

  
• Cori Cycle


  Cyclic biochemical process in which glucose is converted to lactate in muscle tissue, the lactate is reconverted to glucose in the liver, and the glucose is returned to the muscle tissue

  
• Pentose Phosphate Pathway


  Metabolic pathway by which glucose is used to produce NADPH, ribose 5-phosphate, and numerous other sugar phosphates

  
• Transketolase


  • Key enzyme in the non-oxidative branch of the pentose phosphate pathway that transfers a two-carbon aldehyde unit from ketose-donor to aldose-acceptor sugars

  
• Transaldolase


  • Key enzyme in the non-oxidative branch of the pentose phosphate pathway that transfers a three-carbon aldehyde unit from ketose-donor to aldose-acceptor sugars

  
• Insulin


  Hormone produced by the beta cells of the pancreas that promotes the uptake and utilization of glucose by cells, lowering blood glucose levels, and is also involved in lipid metabolism

  
• Glucagon


  Polypeptide hormone produced in the pancreas by alpha cells that is released when blood-glucose levels are low, its principal function is to increase blood-glucose concentrations by speeding up the conversion of glycogen to glucose (glycogenolysis) and gluconeogenesis in the liver

  
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• Metabolism


  Sum total of all chemical reactions in a living organism
• Metabolism


  Provides the source of energy we need for all our activities such as thinking, moving, breathing, walking, talking, etc.
• Metabolism


  Provides energy for many of the cellular processes such as protein synthesis, DNA replication, RNA transcription and transport across the membrane, etc.
• Catabolism


  All metabolic reactions in which large biochemical molecules are broken down to smaller ones, usually energy is released in these reactions

  
• Catabolism


  • Oxidation of glucose
• Anabolism


  All metabolic reactions in which small biochemical molecules are joined to form larger ones, usually require energy

  
• Anabolism


  • The synthesis of proteins
• Metabolic Pathway


  Series of consecutive biochemical reactions used to convert a starting material into an end product
• Types of metabolic pathways

  • Linear
  • Cyclic
• The major pathways for all forms of life are similar
• Practice Exercise


  1. Classify each of the following chemical processes as anabolic or catabolic:

  2. Synthesis of a protein from amino acids

  3. Formation of a triacylglycerol from glycerol and fatty acids

  4. Hydrolysis of a polysaccharide to monosaccharides

  5. Formation of a nucleic acid from nucleotides
• Knowledge cell structure is essential to the understanding of metabolism
• Prokaryotic Cell


  Single compartment organism, no nucleus, found only in bacteria, single circular DNA molecule present near center of the cell called nucleoid
• Eukaryotic Cell


  Multi-compartment cell, DNA is present in the membrane enclosed nucleus, cell is compartmentalized into cellular organelles, ~1000 times larger than bacterial cells

  
• Schematic Representation of a Eukaryotic Cell

  
• Eukaryotic Cell Organelles and Their Function

  • Nucleus: DNA replication and RNA synthesis
  • Plasma membrane: Cellular boundary
  • Cytoplasm: The water-based material of a eukaryotic cell
  • Mitochondria: Generates most of the energy needed for cell
  • Lysome: Contain hydrolytic enzymes needed for cell rebuilding, repair and degradation
  • Ribosome: Sites for protein synthesis

  
• Mitochondria

  An organelle that is responsible for the generation of most of the energy for a cell, outer membrane is permeable to small molecules, inner membrane is highly impermeable to most substances and is folded to increase surface area, synthesis of ATP occurs

  
• Adenosine Phosphates


  • AMP (Monophosphate): one phosphate group
  • ADP (Diphosphate): Two phosphate groups
  • ATP (Triphosphate): Three phosphate groups
  • cAMP (Cyclic monophosphate): Cyclic structure of phosphate
• AMP


  Structural component of RNA
• ADP and ATP


  Key components of metabolic pathways, phosphate groups are connected by strained bonds which require less than normal energy to hydrolyze them