CH 12 Lipids and Cell Membranes P1

Question 1

Membrane Structure

Answer 1

sheet-like
2 molecules thick
form closed boundaries
most are electrically polarized

Question 2

Membranes are composed of?

Answer 2

lipids and proteins

Question 3

Lipids and proteins can be decorated w/?

Answer 3

carbs

Question 4

Membrane Lipids

Answer 4

amphipathic molecules
form closed bimolecular sheets
prevent movement of polar / charged molecules

Question 5

Membrane Proteins

Answer 5

mitigate impermeability of membranes

allow movement of info across cell membrane

Question 6

Membranes are what type of assemblies?

Answer 6

noncovalent

Question 7

Membranes are asymmetric, meaning?

Answer 7

outer surface always diff from inner surface

Question 8

Membranes are what types of structures?

Answer 8

fluid

Question 9

What are the key constituents of Lipids?

Answer 9

FAs

Question 10

Fatty Acids (FAs)

Answer 10

chains of H-bearing C atoms w/ carboxylic acid at one end, methyl group at other.

Question 11

What can be saturated or unsaturated?

Answer 11

FAs

Question 12

FA C atoms are normally numbered beginning w/ the?

Answer 12

carboxyl terminal C atom

Question 13

How do you label the C atoms in FAs?

Answer 13

C2 - alpha

C3 - beta

Question 14

FAs can also be numbered from this group:

Answer 14

methyl C - omega C

Question 15

FA names are based on their?

Answer 15

parent hydrocarbons

Question 16

FAs vary in what properties?

Answer 16

chain length

degree of unsaturation

Question 17

What normally have an even number of C atoms.

Answer 17

FAs

Question 18

What are the most common numbered chains of FAs?

Answer 18

16C and 18C

Question 19

What are the most common db’s in FAs?

Answer 19

cis configuration

Question 20

In polyunsaturated FAs the db’s are sep’d by?

Answer 20

at least one methylene group

Question 21

What enhances the fluidity of FAs?

Answer 21

short chain length

presence of cis db’s

Question 22

Common Membrane Lipid Types

Answer 22

phospholipids
glycolipids
cholesterol

Question 23

Phospholipid Structure

Answer 23

four components:

1. 1-2 FA tails
2. platform
3. phosphate
4. alcohol

Question 24

Common Phospholipid Platforms

Answer 24

glycerol

sphingosine

Question 25

Phosphoglycerides / Phosphoglycerols

Answer 25

phospholipids w/ a glycerol platform

Question 26

How are Phosphoglycerides / Phosphoglycerols formed?

Answer 26

when an alcohol is added to a phosphatide | diacylglycerol 3-phosphate

Question 27

Phosphoglycerides are derived from ____ by ____.

Answer 27

phosphatidate | formation of ester bond btw phosphate and an alcohol

Question 28

Sphingomyelin

Answer 28

common membrane lipid | primary OH of sphingosine esterified to phosphorylcholine

Question 29

Glycolipids

Answer 29

carb-containing lipids derived from sphingosine | carb linked to primary alcohol of sphingosine

Question 30

Cerebrosides

Answer 30

``` simplest glycolipids single sugar (glucose / galactose) ```

Question 31

Gangliosides

Answer 31

branched chain | as many as 7 sugar molecules

Question 32

The carbohydrate components of glycolipids are on the ____ where they ____?

Answer 32

extracellular surface of cell membrane | play role in cell-cell recognition

Question 33

Cholesterol

Answer 33

lipid based on a steroid nucleus | modified steroid, FA chain attached to one one, OH on other end

Question 34

In membranes the OH group of cholesterol interacts w/?

Answer 34

phospholipid head groups

Question 35

Membrane lipids contain which two moieties (properties)?

Answer 35

hydrophilic hydrophobic (aka amphipathic)

Question 36

FA tail components provide?

Answer 36

hydrophobic properties

Question 37

FA alcohol and phosphate components provide?

Answer 37

hydrophilic properties

Question 38

Phospholipids and Glycolipids readily form?

Answer 38

bimolecular sheets in aqueous media

Question 39

Membrane Bimolecular Sheet Formation

Answer 39

amphipathic nature of constituent lipid molecules. | phospholipids and glycolipids spontaneously form lipid bilayers in aq soln.

Question 40

Membrane formation is driven by?

Answer 40

the hydrophobic effect.

Question 41

These stabilize membranes:

Answer 41

van der Waals interactions btw hydrophobic tails.

Question 42

These attractions exist in membranes:

Answer 42

electrostatic and H-bonding | btw polar heads groups and water molecules.

Question 43

Micelles are readily formed by?

Answer 43

ionized FAs

Question 44

Liposomes / Lipid Vesicles

Answer 44

aq compartments enclosed by lipid membrane (bilayer)

Question 45

Protein-Liposome Complexes

Answer 45

investigate membrane protein functions

Question 46

Liposomes

Answer 46

formed via sonicating a mixture of phospholipids in aq soln. | drug delivery systems.

Question 47

Planar Bilayer Membranes

Answer 47

examine membrane properties like ion permeability in presence of voltage diff across membrane.

Question 48

Glycine-Containing Liposomes

Answer 48

formed via sonication of phospholipids in presence of glycine, free glycine removed by gel filtration

Question 49

Lipid Bilayers

Answer 49

highly impermeable to ions / most polar molecules

Question 50

Small molecules can cross lipid bilayers bc

Answer 50

hydrophobicity (lack of polarity)

Question 51

Lipid Bilayers have low permeability for?

Answer 51

ions | polar molecules

Question 52

Membrane Proteins

Answer 52

allow transport of molecules and info across membrane

Question 53

The % of variation in membranes is from?

Answer 53

< 20 to 75

Question 54

Membrane Proteins can by visualized by?

Answer 54

SDS-PAGE | SDS-polyacrylamide gel electrophoresis

Question 55

Membrane Protein types reflect:

Answer 55

biochemistry occurring in cell