Exam 4

Question 1

Naturally Occurring monosaccharides have what? (3 things)

Answer 1

1. have 3-6 carbons in length
2. D-sugars
3. When cyclized, they form 5 or 6 membered rings

Question 2

Aldose

Answer 2

sugar w/ a aldehyde

Question 3

Ketose

Answer 3

sugar w/ a ketone

Question 4

triose, tetrose, pentose, hexose, …

Answer 4

sugar w/ # carbons

Question 5

D-sugar

Answer 5

OH on the second to last C in Fischer is on the right side

Question 6

L-sugar

Answer 6

OH on the second to last C in Fischer is on the left side

Question 7

When drawing fischers the carbonyl has to be on the ______ side

Answer 7

right side
if left- rotate 180

Question 8

Stereochemistry when adding OH to fischerd

Answer 8

OH on down c
wedge = left
dash = right

up carbon is opposite

Question 9

order in classifying a sugar

Answer 9

1. D or L sugar
2. Aldo or keto
3. # of carbons (hexose,heptose…)

Question 10

what forms a furanose (5 membered ring)

Answer 10

Ketohexose

Question 11

what forms a pyranose (6 membered ring)

Answer 11

Aldohexose

Question 12

anomeric c

Answer 12

C that becomes a new chiral center when sugar cyclizes
(usually C1 in pyranose and C2 in furanose)

Question 13

when adding OH’s in Haworth projection

Answer 13

Left in Fischer = up in Haworth
Right in Fischer = down in Haworth

Question 14

when adding the bottom CH2OH to a Haworth

Answer 14

D-sugar = up in Haworth
L-sugar = down in Haworth

Question 15

α-sugar

Answer 15

anomeric c OH will point the opposite direction as the CH2OH of last C

Question 16

β-sugar

Answer 16

anomeric c OH will point the same direction as the CH2OH of last C

Question 17

naming cyclic sugars (3 steps)

Answer 17

1. alpha or beta
2. D or L
3. name of sugar- except drop -se and replace w/ furanose or pyranose

ex: α-D-glucopyranose

Question 18

disacchride

Answer 18

2 cyclic sugars connected by a glycosidic bond

Question 19

Reducing sugar?

Answer 19

sugar that can oxidize to form carboxylates
(aldoses)

Question 20

glycosidic link

Answer 20

the bond from C to O of FIRST sugar unit

Question 21

Benedict’s Test- Reagent? Outcome?

Answer 21

Reagent = Cu2+
Outcome = blue solution changing to red if reducing sugar

Question 22

Tollen’s Test- Reagent? Outcome?

Answer 22

Reagent = Ag+ Salt
Outcome = clear solution to silver mirror if reducing sugar)

Question 23

Naturally Occurring Fatty acids (5 things)

Answer 23

1. 8-24 C
2. have even # of C
3. only carboxylic acids (sometimes alkene-no other functional groups)
4. if unsaturated, have cis alkenes
5. no branching on C chains

Question 24

Saturated Fatty Acid

Answer 24

only C-C single bonds

Question 25

Unsaturated Fatty Acid

Answer 25

contains alkenes

Question 26

Cis alkene

Answer 26

each H on carbon of alkene are on the same side

Question 27

Trans alkene

Answer 27

each H on carbon of alkene are on opposite sides of

Question 28

Saturated FA usually comes from
mammals/fish or plants/chemist

Answer 28

mammals

Question 29

Cis-unsaturated FA usually comes from
mammals/fish or plants/chemist

Answer 29

plants + fish

Question 30

Trans-unsaturated FA usually comes from
mammals/fish or plants/chemist

Answer 30

chemist

Question 31

classifying unsaturated FA

Answer 31

cis/trans- Ω - location of alkene- #C

Question 32

how does the structure of a fatty acid affect the melting point

Answer 32

The strength of dispersion forces affects melting points. The better the stacking of molecules the stronger the dispersion force, which leads to higher melting points.
Cis-unsaturated FA can’t stack well due to the kinks in its structure from the cis alkene so weaker dispersion
Trans-unsat. FA can stack really well so stronger dispersion than cis

Question 33

Saponifiable lipids (simple and complex)

Answer 33

Simple: waxes, triglycerides
Complex: phospholipids, sphingolipids

Question 34

Non-saponifiable lipids

Answer 34

steroids