Gluconeogenesis is

Options

A. Formation of glycogen
B. Formation of ammonia from glucose
C. Formation of glucose from non-carbohydrate sources
D. Breakdown of glucose.

Answer

**Step-by-Step Solution:**

1. **Understanding Gluconeogenesis**: Gluconeogenesis is a metabolic pathway that is crucial for the synthesis of glucose. It is particularly important when the body needs to maintain blood glucose levels, especially during fasting or intense exercise.

2. **Identifying the Correct Definition**: Among the options provided:
- Formation of glycogen: This refers to the process of storing glucose as glycogen, not the synthesis of glucose itself.
- Formation of ammonia from glucose: This is not related to gluconeogenesis; ammonia is a waste product from protein metabolism.
- Formation of glucose from non-carbohydrate sources: This accurately describes gluconeogenesis, as it involves converting substrates like pyruvate, lactate, and glycerol into glucose.
- Breakdown of glucose: This refers to glycolysis or cellular respiration, which is the opposite of gluconeogenesis.

3. **Conclusion**: The correct answer is that gluconeogenesis is the formation of glucose from non-carbohydrate sources. This process is vital for maintaining blood glucose levels in the body.

**Final Answer**: Gluconeogenesis is the formation of glucose from non-carbohydrate sources.

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