Question

Why are triacylglycerols considered more efficient stores of metabolic energy compared to polysaccharides?

a. Higher hydrogen to oxygen ratio
b. Lower hydrogen to oxygen ratio
c. Presence of steroids
d. Greater branching structure

In terms of chemical terms, what is the main reason for the concentrated nature of triacylglycerols for metabolic energy storage?

a. Dehydration
b. Presence of steroids
c. Branching structure
d. High hydrogen content

Why would it be challenging for Gram-positive bacteria to store sulfur similarly to Gram-negative sulfur-oxidizing chemolithotrophs?
a. Lack of PHA (poly-beta-hydroxyalkanoate) polymer
b. Thick proteoglycan cell wall
c. Presence of lipids
d. Inability to perform sulfur oxidation

Answer 1

Triacylglycerols are more efficient for energy storage than polysaccharides due to a higher hydrogen to oxygen ratio, leading to more energy release upon oxidation and their nonpolar nature, which doesn't bind water, making energy storage more concentrated.

Step-by-step explanation:

Triacylglycerols are considered more efficient stores of metabolic energy compared to polysaccharides primarily because of their higher hydrogen to oxygen ratio (answer a), which leads to greater energy release upon oxidation.

Unlike polysaccharides such as glycogen that are hydrophilic and bind to water, triacylglycerols are nearly nonpolar molecules and thus store energy in a more concentrated form without the additional weight of water.

This efficiency comes from the fact that fats and oils are in a more reduced form than glycogen (higher energy per mass) and release more energy per mass upon oxidation.