Lipids Flashcards
terpenes
precursors to steroids and other lipid signaling molecules
built from isoprene (C5H8)
isoprene
C5H8
monoterpenes
C10H16
sesquiterpenes
C15H24
contain 2 isoprenes
diterpenes
C20H32
contains 4 isoprenes
triterpenes
C30H48
contain 6 isoprenes
can be converted into cholesterol and various steroids
tetaterpenes
C40H64
4 isoprenes
steroids
metabolic derivative of terpenes
have 4 cycloalkane rings fused together - 3 cyclohexanes and 1 cyclopentane
super nonpolar
steroid hormones
act as hormones because secreted by endocrine gland into blood stream
travel by protein carriers because nonpolar
can alter gene expression and regulate metabolism
includes testosterone, estrogen, aldosterone, and cortisol
cholesterol
important component of the phospholipid bilayer
mediates membrane fluidity
amphipathic
precursor for steroid hormones, bile acids, and vitamin D
prostaglandin
active lipid compounds derived from arachidonic acid
unsaturated carboxylic acid
acts as a paracrine or autocrine signaling molecules
regulates cAMP
mediates smooth muscle function, sleep-wake cycle, and elevation of temperature
controls production of blood clots, blood flow, inflammation, and induction of labor
constricts blood vessels
saponification
ester hydrolysis of triacylglyerols using strong base
makes soap
soap
can act as surfactant which reduces surface tension
makes things collide
forms micelles
micelles
hydrophobic inside, hydrophilic outside
fatty acids and bile salts secreted by the gallbladder form micelles that increase surface area availability
what type of fatty acid increases fluidity?
unsaturated cis fatty acids because cause kink in the chain
remains liquid at room temperature
trans configuration
E (opposite sides have highest priority)
cis configuration
Z (same sides have highest priority)
how do double bonds affect melting point
decrease melting point
what occurs when triglycerides break down
separate into glycerol and fatty acids
glycerol can convert to glyceraldehyde 3 phosphate
fatty acids can be oxidized into acetyl-CoA (thru beta oxidation)
what occurs when low glucose in the body?
triacylglycerides are broken down
fatty acids from triacylglycerides are oxidized to acetyl CoA which can convert into ketone bodies which can nourish the brain in replacement of glucose
glycerol from triacylglycerides can go into glycerol 3 phosphate and go through glycolysis
What source of fuel provides the most energy?
fats!
neutral phospholipids
have a positive polar group to balance out negative phosphate group
sphingosine
phosphatidylethanolamine
phosphatidylcholine
negative phospholipids
have neutral group combined with negative phosphate group
phosphatidylserine
phosphatidylinositol
diphosphatidylglyerol
How can phospholipids be separated
mass, charge, and solubility
due to unique features in backbone, polar head groups, and fatty acid chain
what is more soluble: charged or neutral head
charged head because they form H bonds
lipids with long hydrocarbon chains have decreased solubility
How does cholesterol act at high temperatures?
Maintains membrane rigidity and structure
How does cholesterol act at low temperatures?
increases fluidity and prevents membrane from solidifying
What is the best type of FA to increase membrane fluidity?
short unsaturated fatty acid tail
What is the worst type of FA for membrane fluidity?
long saturated tails because will cause phospholipids to cluster (found in sphinogolipids)
emulsification
process of bile salts breaking large lipid globules into smaller droplets (micelles)
this increases surface area with hydrophobic inside and hydrophilic outside
lipases
enzymes that digest certain emulsified lipids to facilitate their absorption
hydrolyzable lipids
contain an ester bond which can be cleaved by lipase with addition of water
triglycerols
phospholipids
sphingolipids
waxes
non-hydrolyzable lipids
do not have ester bond
steroids
prostaglandins
fat soluble vitamins
What is cholesterol a precursor for?
steroid hormones (aldosterone, progesterone, estrogen, testosterone, cortisol), vitamin D, and bile salts
What is leptin and insulin made of?
chain of amino acids
signaling lipids
involved in signal transduction pathway or passing of information between and within cells
divided into 2 categories: steroids and fat-soluble vitamins
glycerophospholipids
have glycerol backbone with 2 fatty acid chains that have ester linkages and connected to R groups
the third group is an Oxygen connected to a phosphate group and an X (polar head)
sphingolipids
play a role in signal transduction and cell recognition
particularly impact neural tissue
triglycerides
composed of glycerol head group and three atty acid tails
primarily used for energy storage in adipocytes
bicelles
arrange lipids in lowest energy state by having hydrophobic portion protected on the inside
form a disk like shape and contain a planar region in the middle where there is nothing
fluid mosaic model
describes the structure of the plasma membrane as a mosaic of componenets - including phospholipids, cholesterol, proteins, and carbohydrates- that gives the membrane a fluid character
aquaporins
required for water to pass through cell membrane
transmembrane channel that provides a polar environment for water molecules to pass through
primary active transport
acquires energy through ATP hydrolysis
ex: Na+/K+ pump
secondary active transport
processes the unfavorable movement of a solute against its concentration gradient by simultaneously moving another solute (favorable) down its gradient
symport and antiport
symport
type of secondary active transport in which the favorable solute and unfavorable solute move in the same direction
antiport
form of secondary active transport in which the favorable solute and unfavorable solute move in opposite directioins
What has a higher boiling point: cis vs trans
cis has a higher boiling point
what has a higher melting point: cis vs trans
trans has a higher melting point
What will increase melting point in fatty acids
trans has a higher melting point than cis
the melting point will increase with length of nonpolar, fatty acid tail
What is the purpose of fatty acids?
constituents of complex membrane lipids
stores fat in form of triglycerides
precursors for synthesis of bioactive lipids
fatty acid structure
has a hydrocarbon nonpolar, hydrophobic tail and a hydrophilic (carboxylic acid) head
so the molecule is amphipathic
negatively charged glycophopholipids
serine
inositoldiphosphatidylglycerol
