During conversion of glycerol to pyruvic acid, the first glycolytic intermediate to form is:
## Core Concept
The conversion of glycerol to pyruvic acid involves its integration into the glycolytic pathway. Glycerol, a product of fat metabolism, can be converted into a glycolytic intermediate through a two-step process.
## Why the Correct Answer is Right
Glycerol is first converted to **glycerol-3-phosphate** by the enzyme glycerol kinase. This step is crucial as it activates glycerol for further metabolism. Subsequently, glycerol-3-phosphate is converted to **dihydroxyacetone phosphate (DHAP)**, a glycolytic intermediate, by the enzyme glycerol-3-phosphate dehydrogenase. DHAP can then be converted into glyceraldehyde-3-phosphate and eventually into pyruvic acid through the glycolytic pathway. Therefore, the first glycolytic intermediate formed from glycerol is **dihydroxyacetone phosphate (DHAP)**, which corresponds to option .
## Why Each Wrong Option is Incorrect
- **Option A:** is incorrect because, although it is an early glycolytic intermediate, it is not directly formed from glycerol.
- **Option B:** is incorrect because it is not a direct product of glycerol metabolism that enters glycolysis.
- **Option D:** is incorrect because it is a later intermediate in glycolysis and not the first one formed from glycerol.
## Clinical Pearl / High-Yield Fact
A key point to remember is that glycerol metabolism feeds into glycolysis at the level of **dihydroxyacetone phosphate**, allowing it to be converted into pyruvate and subsequently into glucose or energy through various pathways. This connection is vital for understanding how different metabolic pathways intersect.
## Correct Answer Line
**Correct Answer: C. **