Lipid classification Flashcards
What part of fatty acids is hydrophobic?
hydrocarbon chain
what part of fatty acids is hydrophillic?
terminal carboxyl group with pKA of 4.8
Long chain fatty acids (LCFA) are predominantly..
hydrophobic and must be in association with protein for circulation solubility
at phisiological pH (-COOH)…
ionizes to (-COO-)
the longer the chain…
the more hydrophobic it becomes
Saturated fatty acid
- NO double bonds
- higher energy
unsaturated fatty acids
-carbons have 1 or more double bonds (mono- or polyunsaturates)
double bonds in unsaturated fatty acids
- cis conformation
- cause kinks
- spaced at 3 carbon intervals
double bonds and melting temp
- reduces Tm
- increases fluidity
- prevents it from packing as tightly, can’t form solid as easily
- vegetable oil
increasing chain length and melting temp
- increasing chain length increases Tm
- decreases fluidity
- lard
membrane phospholipids
- typically have LCFA
- contain double bonds to improve fluidity characteristics
fatty acid structure naming
- carbon 1=carboxy carbon
- carbon 2-the carbon to which the carboxyl group is attached is called a-carbon
- carbon 3=b-carbon
- carbon 4=gamma carbon
- the terminal methyl group carbon is called the omega carbon independent of chain length
omega 3 or 6?
Arachidonic acid 20:4(5,8,11,14)
omega 6
20-number of carbons
4-number of double bonds
numbers in parenthesis-the number of the carbon that each double bond begins at
take number of carbons (20) and subtract the last double bond carbon (14)
20-14=6
a-linolenic acid 18:3(9,12,15)
omega 3 or 6?
18-15= omega 3
linoleic acid and a-linolenic acid
- humans cannot synthesize this
- get from plants
linoleic acid
- humans can’t synthesize
- precursor for other shorter omega 6 FA
arachidonic acid
- becomes essential IF linoleic acid is deficient in the diet
- substrate for prostaglandin synthesis
a-linolenic acid
- humans cannot synthesize this
- precursor for omega 3 FA: important for growth and development
short and medium chain FA
4-10 carbons
long chain FA
16-22 carbons
very long chain FA
> 22 carbons
- only present in certain tissues
- nervous system/brain
Where is FA synthesis?
cytosol, elongated at the ER, so it needs to be ready in the cytosol
2 forms of FA
- unesterified
2. fatty acyl esters (esterified fatty acids)
What are the levels of FA in most tissues?
low?
