Which molecule serves as a substrate for gluconeogenesis and triglyceride synthesis?

Which molecule serves as a substrate for gluconeogenesis and triglyceride synthesis?

• A. Fructose
• B. Lactate
• C. Glycerol 3-P
• D. Acetyl-CoA

Answer: (C)

The correct answer is glycerol 3-phosphate, which plays a critical role in both gluconeogenesis and triglyceride synthesis. In gluconeogenesis, glycerol 3-phosphate can be converted to glucose. This process occurs primarily in the liver, where glycerol, derived from the breakdown of triglycerides in adipose tissue, is phosphorylated to glycerol 3-phosphate and then further metabolized into intermediate substrates that ultimately lead to the formation of glucose. In triglyceride synthesis, glycerol 3-phosphate serves as a backbone for the assembly of fatty acids into triglycerides. When fatty acids are activated to their acyl-CoA derivatives, they can be esterified to glycerol 3-phosphate, resulting in the formation of triglycerides, which are then stored in adipocytes. The other choices, while relevant in various metabolic pathways, do not serve directly as a substrate for both gluconeogenesis and triglyceride synthesis: Fructose primarily enters glycolysis rather than being used for gluconeogenesis directly and is not directly involved in triglyceride synthesis in a similar way. Lactate is mainly used in gluconeogenesis, particularly during the Cori cycle; however, it does not have a significant role in triglycer

The correct answer is glycerol 3-phosphate, which plays a critical role in both gluconeogenesis and triglyceride synthesis.

In gluconeogenesis, glycerol 3-phosphate can be converted to glucose. This process occurs primarily in the liver, where glycerol, derived from the breakdown of triglycerides in adipose tissue, is phosphorylated to glycerol 3-phosphate and then further metabolized into intermediate substrates that ultimately lead to the formation of glucose.

In triglyceride synthesis, glycerol 3-phosphate serves as a backbone for the assembly of fatty acids into triglycerides. When fatty acids are activated to their acyl-CoA derivatives, they can be esterified to glycerol 3-phosphate, resulting in the formation of triglycerides, which are then stored in adipocytes.

The other choices, while relevant in various metabolic pathways, do not serve directly as a substrate for both gluconeogenesis and triglyceride synthesis:

Fructose primarily enters glycolysis rather than being used for gluconeogenesis directly and is not directly involved in triglyceride synthesis in a similar way.

Lactate is mainly used in gluconeogenesis, particularly during the Cori cycle; however, it does not have a significant role in triglycer