Question

Which has a higher stored energy potential per gram, glycogen or triglycerides? Explain.

Short answer

Answer: Triglycerides have a higher stored energy potential per gram compared to glycogen, making them the more energy-dense storage molecule of the two.

Step-by-step solution

Understanding glycogen and triglycerides

Glycogen is a large, branched polymer of glucose that is stored in the liver and muscles of animals as an energy reserve. It can be rapidly broken down to release glucose when needed for energy production. Triglycerides are fatty acids, which form the main component of body fat in humans and other animals. They can also serve to store energy, as they are composed of glycerol and three fatty acid chains.

Determine the energy storage capacity per gram of glycogen

Glycogen is a carbohydrate compound and has an energy yield of about 4 kcal (17 kJ) of energy per gram.

Determine the energy storage capacity per gram of triglycerides

Triglycerides are lipids, which have a higher energy content than carbohydrates. They provide approximately 9 kcal (37 kJ) of energy per gram.

Comparing the energy storage capabilities

Comparing the energy yield values of glycogen (4 kcal/g) and triglycerides (9 kcal/g), it's clear that triglycerides store more than twice the amount of energy per gram compared to glycogen.

Conclusion

Triglycerides have a higher stored energy potential per gram compared to glycogen, making them the more energy-dense storage molecule of the two.