Lipids Flashcards
What are lipids?
1.Water-insoluble molecules that can be extracted from tissues by non polar solvents
2.They are not polymers
What reaction releases large amount of energy in lipids
Oxidation of lipids releases large amount of energy
Four functions of lipids
1.Energy storage
2.Insulation
3.Cell membrane structure
4.Communication
5 Types of Lipids
1.Fatty acids
2.Triglycerides (TAGs)
3.Phospholipids
4.Sphingolipids
5.Steroids (Cholesterol)
Fatty exist either as?
FAs exist either as free or esters (TAGs)
Found at high levels in plasma during fasting
How do FAs circulate in the body?
They circulate bound to Albumin
Empirical formula for FAs
(H(CH2)nCOOH)
How long are FA chains usually?
4-40 carbons long
Also have an amphipathic nature (hydrophilic/phobic)
What parts of FAs are hydrophilic/phobic?
The carboxyl head is Polar
The fatty acid chain is non polar
What FAs are most common in plants and animals?
C16 and C18
Difference between saturated and unsaturated fatty acids
1.Saturated fatty acids have no double bonds and are solid at room temp (animals, humans)
2.Unsaturated fatty acids have one or more double bonds cause chain to bend and are liquid at room temp (fish, oils)
Are fatty acids common in nature?
Fatty acids are rare to find in nature and a lot of the times combined to glycerol via condensation reactions to form an ester bond (TAG)
What percentage of lipids consumed are TAGs? Where are they also produced?
90%
The liver also produces them which is transferred to tissues in lipoproteins
TAGs, which are fats, are hydrolysed via what enzyme?
Lipase separates FAs and Glycerol
Can FAs in TAGs be different?
Yes they can be homogenic or heterogenic FAs within the TAG