why fatty acids cannot be taken for gluconeogenesis?

Answer 1

Most fatty acids cannot be converted into glucose unless the glyoxylate cycle is used, the exception being odd-chain fatty acids, which can yield propionyl CoA, a precursor for succinyl CoA. Fatty acids are regularly broken down into the two-carbon acetyl CoA, which becomes degraded in the citric acid cycle. In contrast, glycerol, which is a part of all triacylglycerols, can be used in gluconeogenesis. In organisms in which glycerol is derived from glucose (eg, humans and other mammals), glycerol is sometimes not considered a true gluconeogenic substrate, as it cannot be used to generate new glucose.

Answer 2

1

Answer 3

http://kidshealth.org/kid/diabetes_basics/dictionary/word_fatty_acids.html


In fat catabolism, triglycerides are hydrolyzed to break them into fatty acids and glycerol. In the liver the glycerol can be converted into glucose via dihydroxyacetone phosphate and glyceraldehyde-3-phosphate by way of gluconeogenesis. In many tissues, especially heart tissue, fatty acids are broken down through a process known as beta oxidation which results in acetyl-CoA which can be used in the citric acid cycle. Sometimes beta oxidation can yield propionyl CoA which can result in further glucose production by gluconeogenesis in the liver.

Experimentally when carbohydrates and proteins are deprived, fatty acids can be substrates for gluconeogenesis.

Answer 4

the body has no problem storing excess glucose in the form of fats, but the body cannot turn fats back into glucose. Instead fatty acids are broken down by beta oxidation into 2 carbon units and this is run in the Krebs cycle.