Lipid metabolism Flashcards
(24 cards)
Another name for lipid/fat
Triglycerides
Triglyceride is a
3 carbon molecule calleda glycerol attached to three fatty acid tails
Where are ketone bodies produced in the body ?
In the liver by ketogenesis from excess acetyl CoA
What is Ketosis
metabolic state in which some of the body’s energy supply comes from ketone bodies in the blood
Ketosis will take place when the body needs energy and there is not sufficient glucose available for the body.
What product is released from B-Oxidation of fatty acids
Acetyl CoA
What is the role of carnitine fatty acid oxidation
Transport the activated FA acyl co A into matrix
Fatty acid oxidation can be divided into 3 parts. what are they?
Activation of fatty acids
Transport of FA into mitochondrial matrix
B oxidation of FA
Acyl CoA is the important product of and where does it enter
FA activation
Enters B-oxidation
Why must Acyl Co A pass through the inner mitochondrial membrane
must reach the matrix where B-oxidation enzymes are located
B- oxidation pathway occurs where
Mitochondrial matrix
ATP production from FA oxidation gives a Net of
120 ATP
Ketogenesis produces
a) Acetoacetate
b) Β-hydroxybutyrate
c) Both of the above examples of ketone bodies, made by ketogenesis
c) Both of the above examples of ketone bodies, made by ketogenesis
Ketone bodies can be smelt..
on a person who is fasting (low carb diet)
- Ketosis occurs in the blood In diabetes because
too many ketone bodies are made than can be used by the brain and heart
- Ketosis and ketoacidosis can cause
breathing difficulties and coma
The two major products of triacylglycerol digestion in the small intestine are fatty acids and
monoacylglycerols
The major function for bile released during the digestion of triacylglycerols is to
act as emulsifier
Lipoproteins that transport triacylglycerols from intestinal cells to the bloodstream are called
Chylomicrons
. Before a fatty acid can undergo Beta-oxidation, it must be activated and then shuttled across the inner mitochondrial membrane. The activating agent and shuttle molecule are
CoA and carnitine
B-oxidation allows for ketogenesis which produces ketone bodies - The starting material for the process of ketogenesis is
acetyl CoA
What are micelles and chylomicrons
Free FA and MAGs combine to form small spherical droplets called micelles (smaller than TAGS )
These are then readily absorbed into the intestinal cells - once absorbed they are repackaged into TAGS and packed into chylomicrons which deliver TAGS to the bloodstream
- How are stored fats mobilized for oxidation?
Hormone sensitive lipase hydrolyses the fat releasing free fatty acid and glycerol
Where and how are fatty acids activated prior to ß oxidation? How many ATP equivalents are used?
Fatty acids are activated in the cytosol, requires coenzyme A and worth of 2 ATP
How are fatty acyl-CoAs transported to the site of ß oxidation? Where is the site of oxidation? What is produced during one cycle of ß oxidation?
Fatty acyl CoA are transported from the intermembrane space into the mitochondrial matrix using Carnitine, releases the fatty acid and goes back into the intermembrane. Oxidation of fatty acid occurs in the matrix
