Lipid Catabolism and Ketogenesis Flashcards
Why are triacylglycerols more efficient form of energy storage than glycogen?
Where are triacylglycerols stored? (What type of cell?)
What hormone stimulates the release of free fatty acids when blood glucose levels fall?
Glucagon
Why must free fatty acids be converted into acyl-CoA efficiently?
How are free fatty acids transported in the circulation?
What are the three chemical steps that fatty acids are activated for Beta-Oxidation from the formation of acyl-CoA?
What reaction ensures that the overall biochemical standard free energy is large and negative in the activation for Beta-oxidation?
Where does Beta-oxidation take place?
What is a “carnitine shuttle?”
What is the function of a carnitine shuttle?
What re the key features of a carnitine shuttle?
How are fatty acyl groups transported from the cytosol to the matrix?
What are the four reactions of one round of Bata-oxidation? (Know the structures)
How does a pair of electrons enter the mitochondrial electron transport chain from FADH2?
Is there a difference in the amount of ATP formed by even and odd-chain fatty acid oxidation?
Name the for important componenets of a lipid bilayer
- Glycerophopholipids
- Cholesterol
- Sphingolipids
- Proteins and carbohydrates
Name 4 functions of membranes.
- Provide a barrier
- Compartmentalization of metabolic pathways
- Hold metabolites
- Provide gradients
What is the hydrophobic effect?
What type of interactions will be found between the fatty acid tails of phospholipids in a membrane?
What influences the function of membrane lipids?
Shape causes function
- triangular (up and down facing)–does not form membranes alone
- rectangular–membrane forming, rigidifies
- Short rectangular–fluidizes the membrane
How does chain length of a fatty acid affect solubility?
Solubility decreases as the length increases
How does the number of double bonds in a fatty acid tail affect solubility?
Solubility increases as the number of double bonds increases
How does chain length of a fatty acid affect melting point?
As chain length decreases, the melting point decreases.
How does the number of double bonds affect the melting point of a fatty acid?
The melting point decreases as the number of double bonds increases.
When considering the effect of double bonds of solubility and melting point, how many does carbons do we simulate each double bond to?
One double bond is about 4 less carbons (-4)
What is optimal fluidity?
What influences the fluidity of the membrane?
- Temperature
- Fatty acid composition
Explain why a longer and more saturated fatty acid membrane make-up causes less fluidity
There are more Van der Wals interactions which leads to higher TM and therefore less fluidity
Explain why short and less saturated fatty acid membrane make up leads to more fluidity
There are less Van der Wals interactions which leads to a lower TM and therefore more fluidity
Which lipids do Oligosaccarides sit on?
Glycoconjugate lipids
Explain the absorptionof dietary fats
How is energy generated from a TAG
What is a TAG
Triacylglycerol
How do we release fatty acids from stored TAG?
Triggered by Glucagon signals for low blood glucose which stimulates the release of fatty acids.
Triacylglycerol and water —lipases—> 3 fatty acids and a glycerol
What are micelles?
Spherical shapes of free fatty acids
How are micelles formed?
free fatty acids interacting with eachother
Free fatty acids form what?
Micelles
True or False. Free fatty acids form micelles that may act as detergents.
True
True or False. Cells will keep the concentration of free fatty acids in very high concentrations.
False. Cells keep them in low concentrations. In cells they are rapidly converted to acylCoA or converted to TAG
What do free fatty acids do in the blood circulation?
They bind to serum albumin
What is Beta Oxidation?
Fatty acid oxidation
What are the two phases of Beta-oxidation?
- Activation of fatty acids (conversion of fatty acids to acyl CoA)
- Beta-oxidation (Acyl CoA is converted to acetylCoA) MITOCHONDRIAL MATRIX
