Fatty acids Flashcards
What is the main goal of fatty acid synthesis?
To create long-chain fatty acids from acetyl-CoA for energy storage(production) and cell membrane construction.
What is the overall process of β-oxidation?
β-oxidation involves the repeated removal of two-carbon units from fatty acids, producing acetyl-CoA. This process is coupled with ATP hydrolysis, NAD+ and FAD oxidation, and occurs in the mitochondria.
What happens during the activation of fatty acids in β-oxidation?
Fatty acids are converted into acyl-CoA derivatives by the enzyme acyl-CoA ligase, which requires ATP.
How are fatty acids transported into the mitochondrion for β-oxidation?
Fatty acids are first activated to acyl-CoA in the cytosol. They are then transported across the mitochondrial membrane via the carnitine shuttle, involving carnitine acyltransferase I and II.
What is the first step in each cycle of β-oxidation?
The first step is the oxidation of acyl-CoA by acyl-CoA dehydrogenase, which introduces a double bond between the α and β carbons, forming enoyl-CoA and producing FADH2.
What is the final step in β-oxidation?
The final step involves thiolytic cleavage by β-ketothiolase, which splits the β-ketoacyl-CoA into a new acyl-CoA (two carbons shorter) and acetyl-CoA.
How many acetyl-CoA molecules are produced from palmitic acid (C16) after four rounds of β-oxidation?
Palmitic acid (C16) produces 8 acetyl-CoA molecules after 4 rounds of β-oxidation.
What is the fate of odd-numbered fatty acids during β-oxidation?
Odd-numbered fatty acids produce a propionyl-CoA at the final step, which is then converted to succinyl-CoA and enters the citric acid cycle.
What are the starting materials for fatty acid biosynthesis?
Acetyl-CoA and malonyl-CoA.
How many ATP molecules are produced per cycle of β-oxidation?
Each cycle generates 1 FADH2, 1 NADH and at least 1 acetyl-coa
How are odd-chain fatty acids oxidized differently from even-chain fatty acids?
They produce propionyl-CoA, which can be converted into succinyl-CoA, entering the citric acid cycle.
What is the first metabolic change during starvation?
The body initially uses stored glycogen for energy, which is broken down into glucose for immediate fuel.
What happens after glycogen stores are depleted during prolonged starvation?
After glycogen is depleted, the body switches to fat metabolism for energy production, converting fatty acids into ketone bodies.
What is ketosis
Ketosis is the metabolic process where the liver converts fatty acids into ketones, providing an alternative fuel source for the brain and muscles when glucose is scarce.
How does the body conserve protein during prolonged starvation?
The body reduces protein breakdown by slowing down muscle tissue breakdown and prioritizing the use of fat and ketones as energy sources.
What is gluconeogenesis, and how is it affected in prolonged starvation?
Gluconeogenesis is the production of glucose from non-carbohydrate sources, mainly amino acids and glycerol. In prolonged starvation, it becomes a major process to supply glucose to the brain.
What is the primary function of amino acid catabolism?
To produce ATP for the body.
What happens to amino acids after ingestion in the fed state?
They are broken down in the small intestine and travel to the liver, where they can be used for protein synthesis or converted into glucose or fatty acids.
