Gluconeogenesis pathway

Gluconeogenesis is a pathway that generates glucose from non-carbohydrate carbon precursors such as pyruvate, lactate, glycerol, and certain amino acids.

Certain tissues, such as the brain and red blood cells, are absolutely dependent on glucose as their primary fuel. Ketone bodies aren't sufficient to provide the energy needs of these tissues. In the fasted state glycogen stores are sufficient to supply these tissue's requirement for glucose for approximately one day, so when the body is in the fasted state glucose must be formed from noncarbohydrate precursors, primarily lactate, certain amino acids, and glycerol. Gluconeogenesis is the pathway for converting noncarbohydrate precursors into glucose. The main routes of entry into gluconeogenesis are through pyruvate, oxaloacetate, or dihydroxyacetone phosphate. Most tissues do not have the ability to carry out gluconeogesis. Gluconeogenesis takes place mainly in the liver and to a lesser degree in the cortex of the kidney.

WikiPremed Resources

Integration of Metabolism Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for Gluconeogenesis
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Learning Goals

Proficiency 

Be capable of naming the steps of the gluconeogenic pathway noting the enzymes not in common with glycolysis.

Understand how the primary gluconeogenic precursors enter the pathway.

Have a basic sense of the breakdown of glucogenic amino acids. You don't need to memorize complicated breakdown pathways (that's 2nd semester biochem) but you should probably know which amino acids are one transaminase step away from being a glycolytic or citric acid cycle intermediate.

Know the role of the coenzyme biotin in the pyruvate carboxylase mechanism.

Be able to describe the reciprocal regulation of glycolysis and gluconeogenesis with special focus on the effectors influencing activity of their respective control points phosphofructokinase and fructose-1,6-bisphosphatase.

Be able to describe the Cori cycle as a process by which the liver takes on metabolic load from skeletal muscle during heavy exertion.

Suggested Assignments

The question server contains a general section covering basic concepts from gluconeogenesis, the pentose phosphate pathway, glyocogen metabolism, fatty acid metabolism, the urea cycle, and metabolic integration. After review complete the crossword puzzle for energy metabolism. Here is the solution to the puzzle.

Review the web resources for gluconeogenesis.

Conceptual Vocabulary for Gluconeogenesis