Gluceneogenesis is:

Options

A. formationn of ammonia from glucose
B. breakdown of glucose
C. formation of glycogen
D. formation of glucose from sources other than carbohydrate

Answer

**Step-by-Step Solution:**

1. **Understanding Gluconeogenesis**: Gluconeogenesis is a metabolic process that results in the generation of glucose from non-carbohydrate substrates. This is crucial when carbohydrate sources are limited.

2. **Sources of Gluconeogenesis**: The primary non-carbohydrate sources for gluconeogenesis include proteins (amino acids) and fats (glycerol). This process allows the body to maintain blood glucose levels during fasting or intense exercise.

3. **Definition Breakdown**: The term "gluconeogenesis" can be broken down into three parts:
- "Gluco" refers to glucose.
- "Neo" means new.
- "Genesis" means formation.
Thus, gluconeogenesis literally means the formation of new glucose.

4. **Physiological Importance**: Gluconeogenesis is particularly important in tissues such as the liver, kidneys, and certain cells like red blood cells (RBCs) and the brain, which rely on glucose as a primary energy source.

5. **Evaluating Options**:
- Option 1: Formation of ammonia from glucose - Incorrect.
- Option 2: Breakdown of glucose - Incorrect.
- Option 3: Formation of glycogen - Incorrect.
- Option 4: Formation of glucose from sources other than carbohydrates - Correct.

6. **Conclusion**: The correct definition of gluconeogenesis is the formation of glucose from non-carbohydrate sources.

**Final Answer**: Gluconeogenesis is the formation of glucose from sources other than carbohydrates.

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