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)
Functions of cell membranes
1) SEPARATE interval environment from the external environment
2) provide a SELECTIVE BARRIER: allow only certain molecules to pass thru
3)CONCENTRATE reactants and INCREASE reaction efficiency
4) SEPARATE environments within the cell (organellar functions)
Lipid micelles
single layer of phospholipids
vesicles
double membraned bubble of lipids
Functions of nucleic acids (DNA & RNA)
DNA:
-carries the genetic info
-indirectly controls all cellular functions
RNA:
-messenger molecule for DNA to help code for making proteins
-enzymatic activities-synthesizes proteins
Pyrimidines
CUT
double bonds of oxygen
single ring structure
Purines
AG
larger
double ring
what bond hold the bases of DNA
hydrogen
macromolecules of organisms: RNA
structure:
1st: single strand linked by phosphodiester bonds
2nd: stem-loop hairpins may form by internal H bonding
