Lecture 19 Lipids and Membranes

Question 1

What is a defining characteristics of Lipids

Answer 1

insoluble in water (very hydrophobic)

Question 2

Practice naming

Answer 2

Practive

Question 3

why are most lipids in multiples of 2

Answer 3

bc we want to make an even amount of acetyl coa and its made from acetyl co A

Question 4

which has a higher melting point saturated or unsaturated, why?

Answer 4

saturated,bc they have more energy stored in them

Question 5

Why are saturated fatty acids plaque in blood

Answer 5

bc they are solid at body temp

Question 6

Draw a Triacylglycerol

Answer 6

look it up (dont forget the ester bonds!)

Question 7

what is a “simple” Triacylglycerol

Answer 7

a triglycerol with the same three chains

Question 8

which has more calories and why? (carbs vs fats)

Answer 8

even though bc carbohydrates and fats have same C and H carbs have significantly more Oxygen making it more polar and therefore storining less energy (bc of the electronegativity of oxygen)

Question 9

how do we store fats in our cells

Answer 9

Triacylglycerols

Question 10

What are fat cells called

Answer 10

Adipocytes

Question 11

what are waxes made out of and tell me about it

Answer 11

a veeerrry long chain fatty acid + loooong chain of alcohol,
its as insoluble as you can get there si no part of a wax that can interact with water

Question 12

draw a glycerophospholipid (what are the main compontents?

Answer 12

a glycerol with phosphate hanging off each three things, 2 lipic tails and one “head group”

Question 13

What are the two types of membrane lipids we will be focusing on?

Answer 13

glycerophospholipid and sphingolipids

Question 14

structure of sphingolipid

Answer 14

look it up

Question 15

where are sphingolipids used

Answer 15

in myelin sheaths in you brain

Question 16

what is cholesterol used for

Answer 16

to buffer the rigidity of membranes

Question 17

what fats can make a bilayer and a vesicle

Answer 17

glycerophospholipid and sphingolipids (bc they have two tails)

Question 18

what are micelles formed by

Answer 18

fatty acids and detergents (single chain)

Question 19

is cholesterol animal specific

Answer 19

yes

Question 20

what organ has the highest concentration of coloeter (and makes it)

Answer 20

liver

Question 21

What else do we use cholesterol (sterols) for besides membrane rigidity

Answer 21

sex Hormones

Question 22

does each membrane have a diffrent lipid composition

Answer 22

Yes! they each have diffrent needs

Question 23

do cells measure temperature and adjust their lipid composition to maintain a fluid state?

Answer 23

yes

Question 24

at high temp what could your membranes do to keep fluidity/structure

Answer 24

increase saturate FA

Question 25

at low temp what could your membranes do to keep fluidity

Answer 25

increase unsaturated FA

Question 26

how fast is lateral diffusion

Answer 26

1 mocrom per second! fast!

Question 27

why is moving the outer leaflet to the inner leaflet is slow (takes days) and what is this called

Answer 27

"flip flop" diffusion bc its unfavorable to the polar headgroup

Question 28

What are the 4 different type of ways a thing can flip flop from slowest to fastest

Answer 28

1. Spontaneous (no energy needed so so slow, non specific) 2. P-type flippase (INWARD) movement, specific, ATP required 3. ABC Flippase (OUTWARD) movement, specific , ATP resuwired 4. Scrablease (very fast) Bidirectional, no energy needed, non specific, (why is this not ATP dependent? bc its always going with the concentration gradient, she has no laws)

Question 29

why do you need flipbaes

Answer 29

to make sure that you have the correct orientation of inner things and outer things (or else apoptosis)

Question 30

what lipid associated with cholesterol in rafts

Answer 30

sphingolipids

Question 31

What are rafts used for

Answer 31

signaling centers recognized by proteins

Question 32

if you don't have cholesterol what happens

Answer 32

so much variation in membrane fluidity that would be bad