Exam 2 Lecture 23 Lipids Flashcards
lipids are
amphipathic
the polar head on a FA is
a polar carboxyl head group (hydrophilic)
the nonpolar tail of a FA is
a hydrophobic hydrocarbon
what is the pKa of the head on a FA
4.5
what does it mean for a FA to be saturated?
all single C-C bonds; carbons saturated with hydrogens
what does it mean for a FA to be unsaturated
one or more double bonds; carbons don’t have complete saturation in hydrogens
saturated:
MP:
Flexibility:
Shape of hydrocarbon:
mp is high
flexibility is high
shape of hydrocarbon is linear
unsaturated:
MP:
Flexibility:
Shape of hydrocarbon:
mp is lower
flexibility is low
shape of hydrocarbon depends on cis (bent more) or trans (bent less)
caveat: shorter FAs melt at a _ temperatures than longer FAs
lower temperatures
FAs are #ed from _ to _
carboxyl end to methyl end
alpha-C is carbon # _
carbon # 2 from carboxyl end
examples of omega-3 FAs
linolenic acid 18:3 stearidonic acid 18:4 docosapentaenoic acid 22:5 eicosapentaenoic acid 20:5 docosahexaenoic acid 22:6
examples of omega-6 FAs
linoleic acid 18:2
arachidonic acid 20:4
docosapentaenoic acid: 22:5
why are omega FAs important?
used in cell membrane and other important lipids
common energy source
promote good health
what are the 2 omega FAs that cannot be synthesized by humans
linoleic acid and linolenic acid
a micelle is a _ layer FA that is wedged shaped
single layer
a bilayer is a _ layer FA that is cylindrical
double layer; there are 2 hydrocarbon/FA tails
_ are the majority component of cell membranes
glycerophospholipids
common alcohols added to FAs:
- serine (aa)
- inositol, glycerol (sugar-derivatives)
- ethanolamine, choline (organics)
_ like sphingomyelin attach a FA to an amine
sphingophospholipids
_ are important for ABO blood type antigens and cell signaling
glycosphinogolipids
_ are found in plants and bacteria but rarely in animals
glycoglycerolipids
_ is an important sterol
cholesterol
ceramides are _ and are intermediates for other _
waxy and are intermediates for other sphingolipids
the polar region on waxes is very small therefore:
predominantly hydrobphobic nature of the molecule will repel water
TAGs are composed of _ + _
glycerol + 3 FAs
TAGs are the most common form of _
fat storage molecules
archaeal lipid membranes contain _ FAs
branched
