Ch.27 Flashcards
define a lipid
pg. 3
lipids are essentially hydrophobic small molecules that engage in a biollogically active manner
what are the four many triglecerids and phosphorlibids
pg. 3
- fats (fatty acids, tryglycerides
- waxes
- terpenes
- sterols and steroids
describe a terpene and what is a monoterpene
pg. 4
a simple to highly complex liquid
isoprenes are coupled (joined) together to produce the larger terpenes.
ex. monoterpene consists of two isoprene units - 10 carbons in the system)
draw an isoprene
pg. 4
what is limonene - draw it
pg. 6
limonene is a aliphatic hydrocarbon classified as a cyclic monoterpene
draw the biosynthesis of limonene and label the terpene
pg. 6
draw the monoterpene mechanism
pg. 7
what is the catalytic role of metals (ex. Mg2+ or Mn2+)
pg. 8
metals act as lewis aids –> metals acceptsan electron pair from a donor (Lewis base) –> metals often have vacant orbitals that can accept these electron pairs
draw a cation stack
pg. 9
sesquiterpenes
pg. 10
contain three isoprene units
what is the precursor for a sesquiterpene - identify the isoprenes
pg. 10
called a farnesyl pyrophosphate
what might occur right before a terpene cyclizes, why does this happen, and what would the notation be
pg. 11 and 12
carbocations may not be in the right place to effectively cyclize –> so we need hydride shifts. the notation may look like “1,3H-“ above an arrow
answer practice problem on pg. 13
describe saturated fatty acids
pg. 14
- no double bonds
- solid at room temperature because they can stack really well
- at physiological pH they exist with a deprotonated COOH
draw a saturated fatty acid at a low pH
pg. 14
draw the difference between saturated, monounsaturated, and polyunsaturated fatty acids
pg. 15
draw a polyunsaturated fatty acid at a low pH
pg. 15
draw a monounsaturated fatty acid at a low pH
pg.15
describe unsaturated fats
pg. 14
- have double bonds (one or multiple)
- they are liquid at room temp because the double bond adds a kink in th structure, which prevents effective stacking
are cis or trans unsaturated fatty acids more common
pg. 15
cis unsaturated fatty acids are more common
trans unsaturated fatty acids are rare or synthetic
how is the melting point of fatty acids effected
pg. 16
as surface area increases on the fatty acid, the melting point increases –> because there is more surface area to interact with
why do the melting points of cis vs trans unsaturated fatty acids differ
pg. 17 / 18
the trans unsat. FA contains a trans double bond, which does not introduce a significant kink in the chain –> allows for a more linear structure compared to the cis form, enabling tighter packing of molecules than the cis isomer, but not as tight as the saturated fatty acid.
are lipids water soluble? what happens when they are put in water?
pg. 21
lipids are not water soluble. when they are put in water, these molcules are forced to self assemple
draw and explain the surface monolayer
pg. 21
surface monolayer contains hydrophobic components and is forced out of water to react with itself via LDFs
draw and explain mycel
pg. 21
outside environment os prevented from interacting with inside environment
describe the amphipathic nature of a lipid
pg. 21
at phys. pH –> lipids have a charged head group with a hydrophobic tail –> amphipathic because it can strongly react with itself and with water
describe the ratio of fatty acid existence at different pHs
pg. 22
as basicity increases, the deprotonated COO- is favored
as acidity increases, the protonated COOH is favored
they exist in a ratio
which FA forms complex self assembled shapes at different pHs? which is the most important shape?
pg. 23
unsaturated FAs can form a variety of 3D shapes at varying pHs (saturated FAs are different)
at a pH of 7.5: a cubosome shape is formed which makes up the bilayer at phys pH
describe wax esters
pg. 24
- composed of a fatty acid and an alcohol
- very hydrophobic
- due to ester, the pH isn’t going to really effect a wax –> so we don’t see formations of different structures
- wax is used to build things and to waterproof things (protective barrier)
triglycerides
pg. 26
- the storage method for FAs
- triglycerides are used in many areas (ex. cell metabolism, insulation, etc.)
- they contain three ester residues bonded to a glycerol backbone - which can be further substituted
- enzymes catalyze the production by combining a triol with three fatty acids
simple vs. mixed tricglycerides
pg. 27
Simple triglycerides have the same fatty acid, mixed triglycerides have different fatty acids
more unsaturated fats lower the melting point which makes them liquid at room temp.
hydrogenation of FAs
pg. 28
used in the food industry to convert oils into fats which reduces spoilage and avoids liquid separation
Double bonds present in unsaturated triglycerides can be hydrogenated to convert oils to a semisolid product
hydrogenation is essentially turning an alkene into an alkane which raises the MP of the whole system
describe emulsification
pg. 29
emulsifying agents are added to prevent the separation of food
it is the process of mixing two immiscible phases (e.g., oil and water) with the aid of a surface active agent (emulsifier) into a homogeneous mixture
describe fatty acid spoilage of unsaturated fats and what that means for its degradation
pg. 30
aka - lipid oxidation
ex. olive oil left open in the air will spoil faster because oxygen can get get in, so the oxidation process occurs.
the oxidation process causes primary products to become secondary and then eventually tertiary products
draw the saponification reaction
pg. 31
what undergoes saponification
pg. 31
triglycerides
answer practice question on pg. 32
why are FAs able to form a micelle in water?
pg. 33
they are amphipathic
answer the practice problem on pg. 34
what reactants can be used to do a hydrogenation rxn
pg. 34
FA + H2 –PT–>
removes double bond (hydrogen added to make an alkane)
describe a glycerophospholipid
pg. 35
used in the cell as a semi-permeable barrier
contains two FAs, glycerol, phosphate, and an alcohol
what are the properties of phospholipids
pg. 36
- amphipathic
- form membranes
how can the FA chains effect the membrane
pg. 36
- more fluidity = more unsaturated fats
- more rigidity = more saturated fats
describe sphingolipids
pg. 37
- another lipid found in the membrane
- used to create microenvironments in a membrane
contain sphingosine, fatty acid, phosphate, and an alcohol
draw a sphingosine
pg. 37
aka, the individual units that make up sphingolipids
eicosanoids and draw it
pg. 40
aka icosanoids
- class of messenger lipids based of of arachidonic acids
draw prostaglandins
pg. 40
draw thromboxane
pg. 40
draw leukotrienes
pg. 40
describe sterlods and draw the general structure
pg. 42
these are rigid, hydrophobic biological components
the ring structure makes the compound more rigid (more restrictive rotation) than the typicaly acyclic structure. these compounds add rigidity to overall H-bond netwrok
draw sterol
pg. 42
describe cholesterol
pg. 43
- functions for membrane fluidity, hormone precursor, and vitamin D precursor
- it is a lipid in the blood
draw cholesterol
pg. 43
what does the biosynthesis of cholesterol
pg. 44
ring opening of an epoxide via an acid –> the more substituted side breaks open
how do hormones signal
pg. 47
hormones act as on / off switches –> they bind to specific receptor sites (have a high affinity to specific receptors)
lipoprotein
pg. 48
round particles made of fat (lipids) and proteins that travel in your bloodstream to cells throughout your body. Cholesterol and triglycerides are two types of lipids found in lipoproteins.
- they transport hydrophobic material in water
HDL and LDL function
pg. 49
Cholesterol (hydrophobic) can’t just jump into circulatory system (water) to move about! It has to hitch a ride on lipoproteins Low density lipoproteins (LDLs) and High density lipoproteins (HDLs) essentially describe the lipid loading in a lipoprotein
- the density of lipoproteins is the ration of protein to fat
explain the function of steroids in the digestive system
pg. 50
steroids can be easily oxidized via cytochrome and P450. oxidation becomes bile salt which aid lipid digestion by acting as emulsifying agents