Flashcards in Metabolism of Dietary Lipids Deck (59):
List the different classes of lipids (5)
What makes up a TAG?
Glycerol and 3 fa
Fatty acids usually contain an organic acid group. What is the name of this acid?
What makes up a phospholipid?
glycerol, 2 fa, and at least 1 phosphate group
What type of enzymes will break down lipids?
Lipases and esterases
What type of fatty acid chains do lipase's usually digest and where in the body does this occur?
Short fatty acid chains TAGS in the stomach
Where is the gastric endocrine system activated?
What enzyme will catalyze the hydrolysis of lipids containing fa
What substance of the body all help to emulsify lipids and what is the general mechanism?
They increase reactive surface area by decreasing clumping.
Where are bile salts made, stored, and delivered in the body?
Stored: gall bladder
Do both gastric and lingual lipase's hydrolyze ester bonds in short and medium chain TAGS?
Bile salts are derivatives of what steroid compound?
What hormone will activate the secretion of bile?
The target for the pancreatic enzymes include:
TAG(lipase), Cholesterol ester(esterase), phospholipid digestion(lipase)
What hormone is secreted in response to protein/lipids in the small intestine?
Name a few functions of Cholestystokinin
Decreases gastric emptying, increases bile secretion and the secretion of zymogens activated by trypsin
Secretin acts on what cells in the body?
Pancreas exocrine cells
What does secretin secrete?
Bicarbonate to increase pH
What is the function of the chylomicron?
Delivers food derived fatty acids from the intestine to the cell.
Where are the chylomicrons assembled and secreted to?
In enterocytes and secreted to the lymph system.
If a fatty acid has no double bonds it is called?
Fatty acids that are used for structure such as cellular membranes generally have how many carbons?
Fatty acids with double bonds in biological systems are usually in what conformation?
Fatty acids with chains lengths of 4 to 10 are found in what liquid?
What 2 hormones control the release of fatty acids from adipocytes?
Glucagon and epinephrine
Glucagon and epinephrine will bind to what part of the cell and will activate a signal cascade of what kind of enzyme?
Both bind a receptor on the cell membrane of adipocyte activating protein kinase A (PKA)
By what mechanism does PKA activate the hormone sensitive lipase?
How are fatty acids carried in the blood stream?
In the case where there are more than one double bond the double bonds usually spaced by at least how many carbons?
What are the two essential fatty acids that we cannot synthesize?
Linoleic and alpha-linolenic acid
In humans where does fatty acid synthesis occur?
Lactating mammary glands
What 3 things does fatty acid synthesis require?
What does acetyl CoA require to pass through the inner mitochondrial membrane?
A citrate to pyruvate shuttle
Where do we obtain mitochondrial CoA?
1) pyruvate, 2) ketone bodies, 3) fatty acid breakdown (β-oxidation) and 4) some amino acids
What is the rate limiting step of fa synthesis?
Carboxylation of Acetyl CoA to form Malonyl CoA
What intermediate can cause ACC to polymerize and activates it?
What will deactivate ACC?
Long chain fatty acyl CoA (palmitic acyl CoA) the end product of fatty acid synthesis
A continuous diet of excessive calories will cause and increase in...
acetyl CoA carboxylase enzyme synthesized. This will increase fatty acid synthesis.
The major pathway for catabolism of fatty acids is called?
In Beta-oxidation how many carbon fragments are removed at a time?
What are the end products of beta-oxidation?
What is used to move acyl CoA into the mitochondria?
What happens to the acyl group with the Carnitine Shuttle?
- the acyl group is transferred to the carnitine via carnitine palmitoyl transferase I an enzyme on the outside membrane of the mitochondria.
The acyl carnitine will pass through the inner membrane in exchange for what?
In exchange for free carnitine which passes outside the inner mitochondrial through the same Translocase transporter that acyl-carnitine passed through.
Once inside the mitochondria how is the acyl group freed?
By the enzyme carnitine palmitoyl transferase II (CPT2)
What is the energy production from β-oxidation of one palmitoyl CoA?
It yields 8 acetyl CoA, 7 NADH and 7 FADH2 from which 131 ATP can be generated.
What is the total net ATP production of Beta-oxidation?
The oxidation of saturated or unsaturated yields more energy?
What happens to very long fatty acids during catabolism?
They undergo a preliminary β-oxidation in peroxisomes.
What is the name of the 3 carbon odd numbered fatty acid?
The enzymes to process propionyl-CoA will require other co-enzymes and co-factors what are they?
The carboxylase requires Biotin and ATP
The mutase requires Vit B12
Propionyl-CoA will be converted to what compound and enters what cycle?
Succinyl CoA - TCA cycle
Where does omega-oxidation occur in the body?
Endoplasmic reticulum of liver/kidney
Acetone, and d-beta-hydroxybutyrate and acetoacetate are examples of what type of molecules?
T or F
The liver can easily metabolize ketone bodies
Ketone bodies have the potential to produce how many ATP?
When are ketone bodies produced?
When acetyl CoA in the liver is in excess of the livers oxidative capacity.
What are the two key enzymes in fatty acid synthesis?
Acetyl CoA Carboxylase
Fatty Acid Synthase