Question

What two reasons best explain why fats are the primary energy storage molecule compared to carbohydrates?

- Carbohydrates have a higher oxidized state than fats, so the energy yield is lower per gram of material.
- Carbohydrates contain too many glycosidic bonds that can only be hydrolyzed by probiotic bacteria, fats do not.
- Fats are easier to eat because they are tasty, carbs are bland and tasteless so evolution favored fats over carbs.
There are not two correct answers.
- Carbohydrates are hydrated, which adds more wet weight so would be a burden to carry around carbs.
- Fats have a carboxyl group that helps them to form micelles in the digestive track, whereas carbs are solid

Answer 1

Fats are the primary energy storage molecules due to their higher energy yield per gram and their efficiency in storage, as they do not bind water and therefore occupy less space compared to carbohydrates.

Step-by-step explanation:

The two reasons that best explain why fats are the primary energy storage molecule compared to carbohydrates are: firstly, fats have a higher energy yield per gram because they are more reduced in comparison to carbohydrates, and secondly, carbohydrates are hydrophilic and bind water, which adds weight and bulk, making them less efficient for long-term storage. In other words, the oxidation of fats produces about 9 kcal/g, whereas carbohydrates only yield about 4 kcal/g, so fats can pack over twice the caloric content. Additionally, fats do not bind water, thus they require less space for the same energy content, making them more efficient for energy storage in the body.