Fatty Acids & Ketones Flashcards
When is protein used for energy?
When muscle glycogen stores fail
Describe the structure of a fatty acid
Carboxylic head group with an aliphatic tail
What and where are ketones produced from?
Acetyl-CoA in the liver
Why do lipids form micelles?
Hphobic tails point inwards in circle, so can be broken down by lipase and absorbed
What happens when Triglycerides are transported? (4)
1) Incorporated into Chylomicron
2) Go through lymph system into tissues with Lipoprotein lipase on surface
3) BD and absorbed into tissues
4) Used for energy or converted back to TG
What does ATP cause fatty acids to be converted to? (2 steps)
1) Acyl Adenylate
2) Acyl-CoA
What are the four stages of Fatty Acid B oxidation?
Ultimately overall function for AR
1) Acyl-CoA
2) New double bond
3) New hydroxyl group
4) New carbonyl group
5) Acetyl Co-A produced for K Cycle
What is the carnitine shuttle used for?
Method for fatty acids with more than 14 C to be absorbed through mitochondria
What is Acetyl-CoA used for? (2)
1) Most is utilised in KC for glucose
2) Small proportion converted to ketones
When does ketogenesis occur?
During high rates of fatty acid oxidation if too much acetyl CoA is produced; exceeds the Krebs cycle capacity, so ketones are then produced
5 steps of ketogenesis?
1) 2 Acetyl-CoA
2) Acetoacetyl-CoA
3) HMG-CoA
4) Acetoacetate
5) Acetone and Beta hydroxybutyrate
3 factors affecting ketogenesis?
1) Fatty acid release from adipose tissue
2) Low level of glycerol-3-phosphate
3) If high ATP demand, ACA oxidised to co2 via the KC
(4) levels of glucagon/insulin available)
What happens in Ketoacidosis?
1) Hyperglycaemia
2) Increased acetoacetate and beta hydroxybutyrate
What happens in Ketoacidosis of alcohol abuse?
1) Increased lipolysis (More FA available)
2) Increased ketone production
Consequences of Ketoacidosis?
1) Lower pH of blood as more acidic
2) More difficult for Hb to bind to O2 so results in hyperventilating
