Lipids and Membranes Flashcards by Afia Unknown

what are 4 main components of fatty acid structure ?

amphipathic molecules - hydrophobic
water insoluble
long alkyl chain (hydrophobic)
carboxylic acid polar head

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when is the trend for the melting point on saturated fatty acids

the longer the tail the higher the melting point bc london forces getting stronger

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what about the trend in solubilty of saturated fatty acids ?

solubility in aq sln decreases as chain get longer

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what is an unsaturated and saturated fatty acid

a fatty acid that has more than 1 double bond has a “ kink”
straight chain no bonds for saturated

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what are the usually length ranges of the chain

8-24 usually even number

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what happens to the melting point when you increase the double bonds making it more unsaturated ?

the melting point decrease

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if you compare long chain with a kink (double bond) to a short straight chain who will have the higher mp

the short straight chain will still have the higher melting point

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what is trans fatty acids and how are they formed

its is where they have a trans double bond to have an exteneded conformation and be able to pack more they are formed from partial dehydrogenation of unstaturarated fats

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does cis or trans have high melting point

trans has a higher melting point due to the fact it can pack more tightly

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what is the triaglycerol structure and linkages

that has 3 fatty acids that are esterfied to a glycerol molecule

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what is the main function of triaglycerols , what is the solid ad liquid states ?

the a primary lipid storage (body fat )
the solid are fat
the liquids are oils
THEY ARE NOT COMPONENTS OF CELL MEMBRANES

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what are 2 key comparsion of triaglycerol and water and fatty acids

tria glycerol are less soluble in water than fatty acids due to charges
triaglyccerols are less dense than water (oils and fat float)

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what are the 3 advantages of fats over polysaccharides ?

fats carry more energy
2, fats carry less water
fats are long term , polysaccharides are short term

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what is the structure of phospholipids and linkages (glycerophospolipids) and what do they contribrute to

two fatty aids form from ester linkages with 1st and 2nd hydroxyl group L-glycerol-3-phosphate (charged group in 3 position)
they make up the major component of the cell

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what are sphinolipids ?

they are the second most abundant lipids in plant and animal membrans

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what are the structure of sphinolipids and linkages

the backbone is long chain amino alcohol sphingosine
fatty acid links to sphinogine through an amine linkage
polar head attached

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what are 3 types of sphinolipdis ?

spinogomyliens
cerebrosides
gangliosides

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what is a spinogomylein ?

found in mylein sheath that surrounds nerve cells in animal very abundant

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what are cerebrosides

polar head carbohydrate and make up 12% of white matter

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what are the 3 function of sphinolipids ?

signalling for apoptosis
regulate kinase activity
involved in signal transduction

what are two type of lipids the participate in the membrane

spinolipids and glycophospholipids

what are ganglioside function and where are they found?

they act as receptors with carbohydrate groups on the head and they are found in the brain

what does glycosyltransferases do ?

give us the structure of a sugar by its specific expression

what are sterols/steriod and what are there functions ?

its a 4 fused rings derived from chlorestrols that provides hormones , regulate fluidity an permeability

what are the 6 functions of membranes

1. selective import and export 2. retains ions and metabolism within the cell 3. external signal and transmitting in cell 4. compartmentzlizaion 5. produce and transmit nerve signals 6. store and make ATP

how is the membrane formed in 2 steps

1. individual fatty acids from micelles in water 2, phospholipids and spinogolipids form the bi layer

what is the outside and inside of a membrane

1. outside hydrophilic surface 2. hydrophobic tails

what happens to lipids in the membranes at lower temperature ?

tails stack and membrane rigid

what happens to lipids at higher temperature ?

more movement of tails and great mobility

what is Tm and what 2 things influcences it ?

" transition temperature" where lipids are more mobile and it influenced through the tails, longer tails high tm ( less mobility) and degreee of saturation ( more unstaturation lower Tm ( more mobility)

how do sterols affect the membrane above the tm and below the tm

above the tm the sterol reduces movement of lipids decrease fluidity below tm it prevents lipids from stacking increases fluidity

what do asymmteric lipids do and where can we find them

they have a slow transverse diffustion that leads to asymmetric bilayers in red blood cell molecule

what is the compositions of assymetric bi layers in outer and inner leaflet

1. there is more spinomylein in the outer 2. there is more phosphatidly (choline) in the outer 3. there is more phosphatidyl(ethanolamine) in the inner 4. there is only phosphatyl (serine) in the inner

what are the 2 type of movement between leafets in a lipid bi layer and what is the type of movement

1. lateral diffusion lateral movement is rapid 2. transverse diffusion ( flip -flop ) flipping to the other side is very slow and unlikely

what is the fluid mosiac model of the membrane

1972 it is an envision of protein moving around in a sea of lipids

what 2 things can directly affect the function of a. protein in a membrane ?

mobility and dynamics (orientation can affect)

what are 2 reasons why trans fat is bad for you ?

1. little nutrional value 2, stimulate chlorestoral synthesis and release it into circulation

what are intrinsic (intergral protein membranes

they are membranes embdeed and intracting with the hydrophobic part of the membrane

what are peripheral (extrinsic) membrane proteins )

attached to the outer hydrophilic groups sits on top of membrane

how does anchored proteins attach to the membrane ?

a fatty acid hydrophobic inserts ( anchors ) the protein in the membrane

what are the 4 types of anchored proteins and AAs involced

1. N- myristolation ( glycine) 2. S- -palmo ( cytosine 3. S-prenyl (cytosine 4. glycosyl phos ( any AA)

what are 3 way peripheral ( outer protein) are removed

by changing the salt [ ] cheatling agents pH

how are anchored protein removed ?

enzymic cleavage

how are intergral ( inside) membranes removed ?

using detergents

what is the difference of soluble protein and membrane protein

the distrubtion of AAs as hydrophobic AAs can be on the outside of membrane protein

what protein helps define membrane shape and what protein anchors the skeleton

spectrin shapes ankyrin anchoros

what are transmembrane helices ?

helices that span the whole membrane that contain hydrophobic AA's

what is the amount of saturarted to unstatured fatty acids at low temps ?

at the low temps there is more unstaturated so it can maintain fludity bc unsaturated is able stay fluid bc of low metlting temp at high temps theres more saturared high melting temp