lipids as fuel 1 Flashcards
What kind of molecules are lipids + general forms
Hydrophobic molecules or ampiphillic organic molecules
- Phospolipids
- Sterols
- triacylglecerols
What are the functions and properties of cholestrols and how is it commonly found in diet,(a type of sterol)
function - Bile salts, Hormones, membranes
Found - Cholestrol ester = Cholestrol (4 ringed structure) + long C chain
- rings = hydrophobic
- hydroxyl group = hydrophillic (small at end)
What are TAGs made up from and their function in diet
glycerol + 3 FFA groups - attached via ester links
FFA - Carbon chain attached to carboxylic group
- chain = hydrophobic, carbox = hydrophiliic
TAGs: main form of lipid in diet
- glycerol end, low hydrophilicty
- tails = hydrophobic
What enzymes digest lipids
Different lipases throughout the GIT
Main:pancreatic lipases secreted into the small intestine
- cleaves glycerol at R1 and R3
leaving monoacylglycerol + 2 FFA chains
What is the structure and function of Bile salts
Structure:
Cholic acid - modified varient of cholestrol to make one side more polar
creates 1 hydrophbic face + 1 hydrophillic face
Function: forms a micelle
Bile salts encase TAGs with hydrophbic face inwards hydrophillic face outwards
- provides SA for digestion -> lipase can hydrolise TAGs within
- enables FFA and MAG to be absorbed
How are TAGs transported around the body + function of components
Within lipoproteins (non-polar enviroment within)
made from
phospholipids - enables solubility
unesterified cholestrol - stability
apoproteins - Sturcture of lipoprotein, ligands for cell surface receptors, Cofactors for enzymes
What are the classes of lipoproteins
Chylomicrons - TAG carrier (high TAG, low protein)
VLDL - TAG carrier (less than chylomicrons)
LDL - Cholestrol transport
HDL - Cholestrol regulation + clean up
How can lipopotein types be analysed
Native gel electrophoresis - seperates each lipoprotein appart
Densitometry scan of lipoprotein gels - Visualises the amount of each lipoprotein
What is lipoprotein lipase + where is it found how is it activated
Location: enzymes on the cell wall of endothelial cells - Highest in heart, skeltal muscle and adipose
Function: breaks into TAG -> MAG + 2xFFA
Activated: ApoCII activated lipoprotein lipase
What defects would lead to high levels of TAG or chylomicrons in plasma
defects to ApoCII or lipoprotein lipase
How are FFA and MAG used throghout the tissues
Most cells preferance
Skeletal muscles - Red muscles
Adpose - storage
What is the best method for energy storage throughout the body
Fat primary source of energy - stored in adipose as TAGs
reasons -
1. more stored energy - Further reduced molecule -> can undergo more oxidation
2. storage - non-polar molecules packed very close together
- comparison glycogen requires 2/3 weight as water due to hydrphillic
Why does excess glucose create fasts
When no more energy is required it is stored - body wants to store energy as TAGs
Therefore:
Glycose -> acyl-CoA
acyl-CoA can be turned into FFA -> forms TAGs
