Lipids

Question 1

Fatty acids

Answer 1

long hydrocarbon chain of various lengths (12-24) and degree of saturation of terminated with carboxylic acid group.

Question 2

Increasing chain length..

Answer 2

decrease solubility

Question 3

Palmitic Acid/ Palmitate

Answer 3

16 C

hexadecanoic Acid

Question 4

Linoleic Acid/ Linoleate

Answer 4

18:2 cis 9, cis 12

cis, cis-9,12-octadecadienoic acid

Question 5

Milk contains

Answer 5

fatty acids with 4-10 carbons

Question 6

capric acid/ caprate

Answer 6

10:0

Question 7

lauric acid/ laurate

Answer 7

12:0

Question 8

Palmitoleic acid/ palmitoleate

Answer 8

16:1 cis 9

Question 9

stearic acid/ sterate

Answer 9

18:0

Question 10

palmitic acid is the precursor of other fatty acids (except essential fatty acids)

Answer 10

Structural lipids and triacylglycerol contain fatty acids with at least 16 carbons

Question 11

oleic acid/ oleate

Answer 11

18: 1 cis 9

Question 12

linoleic acid/linoleate

Answer 12

18:2 cis, cis 9,12
cis, cis-9,12-octadecadienoic acid
-precursor of arachidonic acid
-deficiency leads to making arachidonic acid essential
essential
-w 6 fatty acids

Question 13

alpha linolenic acid/ linoleate

Answer 13

18:3 cis, cis, cis 9,12,15
essential
-precursor of other w 3 fatty acids
-deficiency leads to decreased vision and learning behaviors

Question 14

arachidonic acid/ arachidonate

Answer 14

20:4, cis, cis, cis, cis 5,8,11,14

precursor to prostoglandins

Question 15

lignoceric acid/ lignocerate

Answer 15

24:0

Question 16

nervonic acid/ nervonate

Answer 16

24:1 cis 15

Question 17

What is the function of lipids

Answer 17

cell membranes

• energy storage
• cell signaling

Question 18

Phospholipids

Answer 18

glycerol
polar head group
-two nonpolar tail groups

Question 19

sphingomylin

Answer 19

nonglycerol containing phospholipid

-contains spigosine (modified serine_

Question 20

Glycolipids

Answer 20

substitued serine

• 2 catty acids
• carbohydrate (glucose)

Question 21

triacylglycerol

Answer 21

glycerol
three fatty acids
- accumulates as fat droplets in cytoplasm

Question 22

cholesterol

Answer 22

precursor to steroid hormones,
-27 carbons
4 rings (A,B,C,D called steroid nucleus)
-substituted perhydrocyclopentanopenanthrene

Question 23

Micelle

Answer 23

formed by ionized fatty acids. steric constraints precent formation by phospholipids and glycolipids, which preferntially form vesicles

Question 24

phospholipid bilayers contain

Answer 24

phospholipids, glycolipids and cholesterol

Question 25

Energy consideration formation

Answer 25

hydrophobic interactions between fatty acid tails

-electrostatic and hydrogen bond between head group and water molecules

Question 26

transmembrane protein

Answer 26

protein passes through both layers of the bilayer

-extraction requires detergent or organic solvent

Question 27

Peripheral

Answer 27

attached to one side of membrane

• associated with polar head groups.
• extraction requires increase in ionic strength or change in pH

Question 28

Bacteriorhodopsin

Answer 28

archaeal protein

• uses light energy to transport protons out of the cell to create protein gradient
• seven alpha helixes span membrane

Question 29

glycophorin

Answer 29

red blood cell membrane protein

-single alpha helix spans membrane

Question 30

hydrophobic alpha helixes can be identified by plotting

Answer 30

hydropathy index
-plot sliding 20 amino acid average of free energy change when a helical segment moves from interior of membrane to water

Question 31

Plotting hydrophathy is not able to detect

Answer 31

beta barrels

Question 32

Porin

Answer 32

E.coli and Rhodobacter capsulatus

-allows movement of material across the membrane

Question 33

Membrane fluidity is controlled by

Answer 33

fatty acid composition and cholesterol content

• fatty acids exist rigid state or fluid state
• change of state occurs abruptly at Tm:
• length of fatty acid
• degree of saturation

Question 34

lower Tm

Answer 34

shorter fatty acids

more double bonds

Question 35

cholesterol

Answer 35

membrane antifreeze and coolant