Exam 4 Flashcards
Naturally Occurring monosaccharides have what? (3 things)
- have 3-6 carbons in length
- D-sugars
- When cyclized, they form 5 or 6 membered rings
Aldose
sugar w/ a aldehyde
Ketose
sugar w/ a ketone
triose, tetrose, pentose, hexose, …
sugar w/ # carbons
D-sugar
OH on the second to last C in Fischer is on the right side
L-sugar
OH on the second to last C in Fischer is on the left side
When drawing fischers the carbonyl has to be on the ______ side
right side
if left- rotate 180
Stereochemistry when adding OH to fischerd
OH on down c
wedge = left
dash = right
up carbon is opposite
order in classifying a sugar
- D or L sugar
- Aldo or keto
- # of carbons (hexose,heptose…)
what forms a furanose (5 membered ring)
Ketohexose
what forms a pyranose (6 membered ring)
Aldohexose
anomeric c
C that becomes a new chiral center when sugar cyclizes
(usually C1 in pyranose and C2 in furanose)
when adding OH’s in Haworth projection
Left in Fischer = up in Haworth
Right in Fischer = down in Haworth
when adding the bottom CH2OH to a Haworth
D-sugar = up in Haworth
L-sugar = down in Haworth
α-sugar
anomeric c OH will point the opposite direction as the CH2OH of last C
β-sugar
anomeric c OH will point the same direction as the CH2OH of last C
naming cyclic sugars (3 steps)
- alpha or beta
- D or L
- name of sugar- except drop -se and replace w/ furanose or pyranose
ex: α-D-glucopyranose
disacchride
2 cyclic sugars connected by a glycosidic bond
Reducing sugar?
sugar that can oxidize to form carboxylates
(aldoses)
glycosidic link
the bond from C to O of FIRST sugar unit
Benedict’s Test- Reagent? Outcome?
Reagent = Cu2+
Outcome = blue solution changing to red if reducing sugar
Tollen’s Test- Reagent? Outcome?
Reagent = Ag+ Salt
Outcome = clear solution to silver mirror if reducing sugar)
Naturally Occurring Fatty acids (5 things)
- 8-24 C
- have even # of C
- only carboxylic acids (sometimes alkene-no other functional groups)
- if unsaturated, have cis alkenes
- no branching on C chains
Saturated Fatty Acid
only C-C single bonds
Unsaturated Fatty Acid
contains alkenes
Cis alkene
each H on carbon of alkene are on the same side
Trans alkene
each H on carbon of alkene are on opposite sides of
Saturated FA usually comes from
mammals/fish or plants/chemist
mammals
Cis-unsaturated FA usually comes from
mammals/fish or plants/chemist
plants + fish
Trans-unsaturated FA usually comes from
mammals/fish or plants/chemist
chemist
classifying unsaturated FA
cis/trans- Ω - location of alkene- #C
how does the structure of a fatty acid affect the melting point
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
Saponifiable lipids (simple and complex)
Simple: waxes, triglycerides
Complex: phospholipids, sphingolipids
Non-saponifiable lipids
steroids
