Biochemistry : Other Gluconeogenesis Concepts

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #1 : Other Gluconeogenesis Concepts

Which of the following is not true about the gluconeogenesis pathway's role in organismal homeostasis? 

Possible Answers:

Gluconeogenesis is a pathway for cells to create glucose from various precursors when glucose itself is unavailable

Gluconeogenesis is primarily restricted to the liver and kidneys in mammalian species

Gluconeogenesis will typically remain quiescent if the cell has an overabundance of energy from other pathways

Gluconeogenesis occurs when an organism consumes abnormally high amounts of carbohydrates and fatty acids

Pyruvate and glycerol can be substrates for conversion to glucose in gluconeogenesis

Correct answer:

Gluconeogenesis occurs when an organism consumes abnormally high amounts of carbohydrates and fatty acids

Explanation:

Gluconeogenesis occurs in times of starvation, fasting, and low access to sources of glucose. This is the cells way of creating its own precursor when none is available, albeit at a high energetic cost (one cycle of gluconeogenesis can cost 6 ATP). Thus, it is untrue that gluconeogenesis occurs during high consumption of carbohydrates and fatty acids. Each other selection is true regarding gluconeogenesis. 

Example Question #202 : Carbohydrate Metabolism

During anaerobic conditions, lactate travels from the muscle to the liver via the bloodstream. 

What is lactic acid converted into when it reaches the liver before it returns back to the muscle?

Possible Answers:

Acetyl-CoA

Citrate

Glycogen

Glucose

Glucagon 

Correct answer:

Glucose

Explanation:

The Cori cycle comes into play during anaerobic conditions; where lactate from glycolysis travels from the muscle to the liver to be converted into glucose via gluconeogenesis. The glucose is then sent back to the muscle to be used for energy. Note that some of the lactate that is converted into glucose can be stored as glycogen in the liver, but glycogen is not transported from the liver to the skeletal muscle. 

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