Lipids

Question 1

What are lipids defined by?

Answer 1

Hydrophobicity

Question 2

How are they linked together?

Answer 2

Covalently

Question 3

How to separate lipids?

Answer 3

TLC/gel = polarity (np elutes first)
Methyl esters = chain length and saturation

Question 4

What are fatty acids the building blocks for?

Answer 4

Lipids

Question 5

Structure feature of fatty acids

Answer 5

Carboxylic acid and hydrocarbon tail

Question 6

Saturated fatty acids

Answer 6

no dbl bonds (max hydrogens)

Question 7

What do unsaturated fatty acids have?
Why is it less Energy to disrupt packing?

Answer 7

dbl bonds (cis formation)
bcs of the kink in the double bond

Question 8

Labelling fatty acids - Where is C1 located? What is the last C

Answer 8

Carboxyl C
Omega

Question 9

Labelling fatty acids - delta = describe this 18:2 (triangle 9,12)

Answer 9

18 = number of carbons
2 = number of double bonds
9 and 12 = location of double bonds

Question 10

Labelling fatty acids - omega

Answer 10

start at omega carbon and only tellus us location of first double bond

Question 11

Features of fatty acids

Answer 11

even number of carbons. unbranched, dbl-single-single-d-s-s

Question 12

Name the 5 saturated fatty acids

Answer 12

Laureate (12), Myristate (14), Palmitate (16), Stearate (18), Arachidate (20)

Question 13

What are trans fatty acids?

Answer 13

partial hydrogenation of unsatt fatty acids

Question 14

What happens to the solubility and mp of fatty acids when chain length increases?

Answer 14

mp increases
solubility decreases

Question 15

Anhydride

Answer 15

O=C-O-C=O

Question 15

Ester

Answer 15

CH2-O-C=O

Question 15

What is a triglyceride? What are they linked by?

Answer 15

3 fatty acids and a glycerol (ester linkages)

Question 15

Are triglycerides hydrophobic?

Answer 15

yes

Question 16

Phosphoglycerides are amphipathic because…?

Answer 16

Hydrophobic tail and hydrophilic head

Question 17

Phosphoglycerides - What are the highly polar charged groups?

Answer 17

Choline (lecithin)
Ethanolamine
Serine
Glycerol

Question 18

Phosphoglycerides - draw choline

Answer 18

-CH2-CH2-N+(CH3 above and below)-CH3

Question 19

Phosphoglycerides - draw Ethanolamine

Answer 19

-CH2-CH2-NH3+

Question 20

Phosphoglycerides - draw Serine

Answer 20

-CH2-CH(-COO above)-NH3+

Question 21

Phosphoglycerides - draw glycerol

Answer 21

-CH2-CH-(-OH above)CH2-OH

Question 22

Phosphoglycerides - draw the hydrolysis of choline (1 glycerol, 2 fatty acids, 1 phosphoric acid, 1 choline)

Answer 22

Refer to notes for answer

Question 23

What are the structural properties that determine the melting temperatures of various fatty acids?

Answer 23

Chain length
Degree of unsaturation

Question 24

Why are triacylglycerols such a good source of fuel storage?

Answer 24

Because they are insoluble in water large amounts can be stored in cells without increasing the osmotic pressure of the cytosol. The hydrophobicity also allows the storage of TAGs without the added weight of hydration

Question 25

What is the best way to identify fatty acids?

Answer 25

gas liquid chromatography