Structure And Function Of Lipids Flashcards
Lipids:
- structure
3 fatty acids bound to glycerol called a triglyceride
Glycerol:
- structure
Propane-1,2,3- triol
Saturated vs unsaturated
Saturated lipids are solid fats, that contain only carbon single bonds and keep a compact structure
Unsaturated lipids are liquid oils, that contain some carbon single and double bonds that cause the fatty acid to be branched creating the oil
Trans vs Cis fatty acids
Trans and acid are both unnatural, and consist of some carbon double bonds
Trans FA: elaidic acid
Via FA: oleoic acid
Full saturated form is called stearic acid
Naming polyunsaturated FAs
Skeleton structure
18:1 signifies that the lipid is 18 carbons long and the 1 is the double bond of present
Phospholipid:
- structure and function
2 FAs, glycerol, phosphate attached to an alcohol
Function: hydrophobic exclusion forces phospholipidsnintonparticualr higher level structures, a hydrophilic head and a hydrophobic tail
A Micelle is formed by detergent molecules
The phospholipids form a phospholipid bilateral
Phospholipids:
- types
Phosphatidyl choline Ethanolamine Serine Inositol Glycerol
Triacylglycerols:
- melting point
Form a solid form by van der Waals interactions between the acyl chains
The presence of unsaturated FAs is a triacylgylcerol reduces the molecular lacking, so that less energy is needed for melting
Oil transformation to fats
By hydrogenation of adding hydrogen across double bonds in the acyl chains (saturating the double bond)
Fats:
- energy source
Can be used in mitochondria to form ATP, via conversion to acetyl CoA (by glycolysis)
Lipid storage
Adipose cells
Lipid energy output
9 kcal g-1
Lipid characteristics
Water insoluble
Lipophilic
Combination of many fatty acids to form a fat
Formation of an ester bond, allowing the formation of several layers or sheets
Trans fats:
- diet and health
Increase CVD as there is an increase LDLs and a reduction in HDLs
Increase in trans fats consumption 2% equates to a 23% increase in CVD risk
Lipid absorption
- Bile salts emulsify dietary fats in SI forming micelles
- Intestinal lipases degrade
Triacylgylcerols - FAs and other prods taken up by intestinal mucus and converted to triacylgylcerols
- Triacylgylcerols are incorp with cool and apolipoprots into chylomicrons
- Chylomicrons move through lymph and blood to tissue
- Lipoprot lipase convert triayclegylcerols to FAs and glycerol
- FAs enter cells, are oxi as fuel or reesterified for storage
Lipoprot lipase location
Attached to blood capillary walls
Fatty acid oxidation:
- stages
- Oxi conversion of 2-carbon units from the carboxyl end of the FAs into acetyl CoA (Beta oxi), accompany gem NADH and FADH2
- Oxi of acetyl CoA in TCA gen NADH and FADH2
- Oxi phospho; electrons transferred from NADH and FADH2 to O2 gen ATP
Beta oxi
- location
Mitochondrial matrix:
- small FAs diffuse freely across mito mem
- larger FAs transporters via carnitine transporter
Beta oxidation:
- overview
- Dehydro; remove 2H, double bond at C2-3 FAD reduced (trans-2-wnoyl CoA)
- Hydration; addition of water (L beta hydroxy acyl CoA)
- Dehydro; remove 2H, NAD reduced (Beta ketoacyl CoA)
- Thiolysis; formation of acetyl-CoA
ATP
Adenosine Trios Phosphate
Cholesterol absorption:
- small intestines
From intestinal lumen:
- facilitated diffusion of Na/gluc
- Na/gluc symporter
- brush border sucrase
Cholesterol:
- hydrophobic effect
- characteristics
Forms a ball, hydrophilic outside and hydrophobic outside
Amphiphilic
Cholic acid
- chemical structure
Many OH and COOH
Triacylglycerol:
- consists of
Cholic acid + assoc with triacylglycerols forms a triacylglycerols
Triacylglycerols:
- characteristics
Major energy store, highly reduced (38 JKg-1), anhydrous storage and stored in adipose cells
Linked by Ester bonds (linkages)
Lipolysis:
- breakdown
Triacylglycerols breakdown into glycerol and FAs to be broken down to glucose in the liver and FAs to other tissues for B oxi
Lipoproteins:
- structure
Contain triacylglycerols and cholesteryl esters, surrounded by phospholipids, cholesterol and apoplipoproteins
Cholesterol:
- conversion
Chol + FAs + ATP —> cholesterol esters
Cholesterol conversion:
- hormones
C18: oestrogen
C19: androgens
C21: gluco/mineralocorticoids (cortisol and aldosterone)
