exam 1: lecture 2 Flashcards
Functions of lipids
a) structural function ( membranes)
b) signal transduction outside/inside a cell
c) energy nutrient
d) nutrient storage
Why are lipids regarded as macromolecules?
high molecular weight and their importance in cellular structure
features of lipids
- large portion is hydrophobic (little like for water)
amphipathic: regions with polar/ nonpolar
functions: energy storage, membrane structure, signal transmission
What are the 6 main classes of lipids?
1) fatty acids
2) triacylglycerols
3) phospholipids
4) glycolipids
5) steroids
6) terpines
Lipids: fatty acids
a long amphipathic, unbranched hydrocarbon chain with carboxyl group at one end
-> head: polar carboxyl group
-> tail: nonpolar hydrocarbon chain (12-20 carbons)
-even carbon numbers are preferred because synthesis is adding 2-carbon units to the growing chain
-highly reduced-> yield a large amt of energy upon oxidation
lipids: saturated fatty acids
each carbon is bonded to the max number of hydrogens
-takes a lot of energy to break apart due to the talks stick tgt
-long straight chains that pack tgt well
lipids: unsaturated fatty acids
one or more double bonds-> bends in the chains and less tight packing
takes less energy to break apart due to tails pushing away from each other
lipids: triacylglycerols
storage lipids
*triacylglycerols (triglycerides): glycerol molecule with a free fatty acids attached to it
_monoacylglycerols: single fatty acid
_ diacylglycerol have 2
*glycerol: a three carbon alcohol with a hydroxyl group on each carbon
what bond binds glycerols to fatty acids
ester bond- form by removal of water
Triacylglycerol function
1) energy storage
2) protection against cold
*saturated fats are solid/ semi solid at room temps aka fats
- unsaturated are liquid at room temp in temps
lipids: phospholipids
important to membrane structure due to their amphipathic structure
1) phosphoglycerides
2) sphingolipids
phospholipids: phosphoglycerides
predominant phospholipids
basic components:
-phosphatidic acid: 2 fatty acids and a phosphate group attached to glycerol
-have a small hydrophilic alcohol linked to the phosphate by an ester bond
what is alcohol that is polar head group?
serine, ethanolamine, choline, inositol
ex: fatty acids
polar head (hydrophilic):serine-phosphate-glycerol
phospholipids: sphingolipids
based on the amine sphingosine (long hydrocarbon chain w a single site unsaturation near polar end
form an amide bond to a long fatty acid-> ceramide (neurons
phospholipids: glycolipids
specialized membrane components
lipids that have carbohydrate instead of phospholipids
phospholipids:steroids
a 4-ring-hydrocabon skeleton
nonpolar-hydrophobic
differ by position of double bonds and functional groups
most common: cholesterol (insoluble)
