Introduction to Metabolism

1. Identify the key aspects of studying metabolism.

2. Define anabolism, catabolism, committed step, rate-limiting step and steady- state.

3. Explain the general types of metabolic regulation.

4. List the three energy storage forms and the five primary circulating fuels.

5. Identify where specific biochemical processes occur in the cell. (Review "The Cell")

Thermodynamics in Metabolism

1. List the general features and functions of ATP.

2. Define high energy phosphate transfer potential and identify ATP, phosphocreatine , 1,3- bisphosphoglycerate and phosphoenolpyruvate as high energy phosphorylated compounds.

2. Identify the various electron carriers.

3. Discuss the concepts of free energy change (DG) of reactions, the relationship between DG and DG⁰, and the equilibrium constant (Keq).

4. Describe the significance of the adenylate kinase reaction in metabolic regulation.

Gluconeogenesis / Pentose Phosphate Pathway

1. Describe how the oxidative and non-oxidative branches of the pentose phosphate pathway affect glycolysis.

4. Draw structures for the gluconeogenic precursors and products identify the enzymes that differ from those of glycolysis.

5. Describe the Cori and glucose-alanine cycles, and their relationship to gluconeogenesis.

Digestion & Absorption of Proteins & Carbohydrates

1. Delineate the roles of gastric acid during digestion in the stomach.

2 List and distinguish the proteases involved in gastric, pancreatic, brush border surface and intracellular cleavage of peptide bonds; define their specificity in general terms.

3. Describe the absorption of proteins and the five transport systems.

4. Explain the physiology of celiac sprue, cystinuria and Hartnup disease

5. Compare and contrast the two polysaccharides of starch, amylose and amylopectin.

6. List the products of starch digestion by salivary and pancreatic a-amylase.

7. Describe carbohydrate digestion and a-glucosidases.

8. Distinguish between digestible and non-digestible carbohydrates.

Insulin and Glucagon

1. Compare and contrast the structures of preproinsulin, proinsulin and insulin.

2. Describe the six steps associated with the synthesis of preproinsulin and its conversion to proinsulin and the sequence of events from transcription to exocytosis.

3. List the order of events in pancreatic processing of preproglucagon.

4. List the major metabolic effects of insulin and glucagon in liver, muscle and adipose cells.

5. Identify the general structural features of the insulin receptor.

6. Discuss the relationship of interchain autophosphorylation of tyrosine residues in the insulin receptor to intracellular insulin action.

Case Study

1. Describe the biochemistry of insulin-dependent diabetes mellitus (IDDM) and explain why the disease might not appear until after a viral infection.

2. Explain why glycosylated hemoglobin levels (AGE's)can be elevated in insulin-dependent diabetes mellitus.

Allosteric Regulation

1. Review the role of adenylate kinase in regulation.

2. Compare the kinetic characteristics of glucokinase and hexokinase, and discuss their regulation.

3. Describe how phosphofructokinase and pyruvate kinase are regulated allosterically.

4. Identify the key aspects in pyruvate carboxylase regulation.

5. Describe the coordinated allosteric regulation of glucose metabolism, especially in terms of cell energy levels, blood glucose conditions and relative amounts of glucose-6- phosphate.

© Dr. Noel Sturm 2004