Lipids

Question 1

What are lipids soluble in

What are the not soluble in

Answer 1

Water insoluble molecules that are soluble in organic solvents

Question 2

What are lipids roles

Answer 2

In membranes

Energy storage

Signaling

In fat soluble vitamins

Question 3

What are fatty acids

What are they used for

Answer 3

Chain of carbons with carboxylic acids groups at the end

fuel in metabolism

Building block for membrane lipids

Question 4

What is better, cis or trans fatty acids

Answer 4

Trans because they can be closer together to other fatty acids

Question 5

Fatty acids have both ______ and ______
Names

Answer 5

Common

Systematic

Question 6

If it has 18 carbons and is a double bond what is the systematic name for this fatty acid

Answer 6

Octadecenoic acid

Question 7

What if the effect of a double bond being closer to the head of a fatty acid

Answer 7

The impact is big

Question 8

What’s another way to name fatty acids

Answer 8

Using ratios

Ex. Octadecatrienoic acid has a ratio of 18:3

(18 carbons: 3 double bonds)

Question 9

What is the omega carbon in a fatty acid

Answer 9

The very last carbon at the end of the hydrocarbon chain (not the COOH end)

Start from this and count to the double bond to find the position of the db

Question 10

How do we name fatty acid that have double bonds

Answer 10

See if cis or trans

Found where db is (from omega end)

Name the chain

Ex. If db is at carbon 9 and cis

cis-triangle^9-octadecenoate

Question 11

What is special about fatty acids in animals

Answer 11

There usually an even number of carbons In The chain

16 and 18 carbon chain are most common

Double bonds are usually separated by at least one methylene (ch2) group

Usually cis db

Question 12

What do the properties of fatty acids and the lipids derived from them depend in

Answer 12

depend on their chain length and degree of unstaruation (number of db)

Question 13

What affects the melting point of fatty acids

Why

Answer 13

If comparing two fatty acids, The longer chain has a higher melting point if both have same amount of unsaturated

The more unsaturated (more db) has lower melting point

Vanderwaals as well as kinks that make it not so tightly packed and reduces the hydrophobic interactions

Question 14

What part of a fatty acid has the most affect on its melting point

Answer 14

The amount of double bonds has more affect than the length of the chain

This melting point changes much more if double bonds

Question 15

What fatty acids can humans not make

What do they do

Answer 15

The omega 3 fatty acids

They are precursors to some hormones and polyunsaturated

They protect against heart disease (ex. EPA fatty acid and DHA fatty acid)

Question 16

Memorize slide 14 in I pad pics

Answer 16

MEMORIZE

Question 17

What does alpha indicate in example alpha linolenate

What about gamma

Answer 17

Omega 3

Omega 6

Question 18

What are fatty acids stored as in the body and why

Answer 18

Storage as triacylglycerols (3 fatty acids, glycerol backbone) held together by ester bonds

They are neeeded as an energy source but their concentrations in the cells/blood are low since they’re acids

Question 19

What are triacylglycerols

How are they stored

Answer 19

They are hydrophobic, almost anhydrous (don’t contain water)

Stored in specialized adipose cells (also for mobilization)

Adipose cells also provide insulation

Question 20

What are glycerolipids

Answer 20

Made of four things:

2 fatty acids

Glycerol backbone

Phosphate attached to the back bone (negative charged)

(Head group) Alcohol attached to the phosphate

Question 21

What are sphingolipids

Answer 21

They can pack more tightly together than glycerolipids

They can form hydrogen bonds

The only difference of them compare to glycerolipids is that they’re backbone is a sphingosine and only one fatty acid chain bound to the amide group

Question 22

What are glycolipids

Answer 22

Lipids that have a sugar (glucose or galactose) instead of just a regular head group

Ex. Cerebroside (if one sugar)

Question 23

What are phosphoglycerolipids

Answer 23

The simplest phospholipids

Same as glycerolipids, but not alchohol head group (something other than alcohol

Anything with “phosphatidyl” before the head group

Question 24

What is PS charge

Answer 24

-1

Question 25

What is PE charge

What is it lacking

What can it do

Answer 25

Neutral

Has no COOH group on its head group

H bond

Question 26

What is PC charge

What is special about it

Answer 26

Neutral

Has three methyl groups on its head nitrogen (bigger head group)

Question 27

What is PI charge

What’s special

Answer 27

-1

It has a head group in a chair conformation

Question 28

What is diphosphotidylglycerol (CL)

Answer 28

Type of phospohyglycerolipid

Has 4 side fatty acid chains and glycerol back bone in the middle

Has -2 charge

Question 29

What are steroids

Answer 29

They’re important for membrane fluidity

Not in prokaryotes but In all animal membranes

Ex. Cholesterol

Question 30

What does cholesterol do to the membrane

What does it have to do

Answer 30

It has a large bulky non polar tail and a tiny oh head group

This makes it rigid and decreases fluidity of the membrane

It has to go deeper into the membrane so that the large hydrophobic rings don’t interact with the polar groups of the membrane surface.

It has to anchor itself into the membrane

Question 31

What are lipid vesicles or “liposomes”

Answer 31

The bilayer has an outer and inner aqueous compartment and forms a circle with water inside

PC is more likely in the outside because it has a large head group

PE is more likely on the inside because of small head group

Question 32

What is special about the curvature of liposomes

Answer 32

The curving is different depending on the size of the liposome

And the curving affects how the lipids in the lipsome pack