Carbohydrates Flashcards
1
Q
Monosaccharides
A
- Sugars
- Aldoses vs Ketoses
2
Q
Stereochemistry
A
- D and L designation based on Glyceraldehyde
- D is R, L is S
3
Q
Aldoses
A
- Enatiomers: mirror images
- Epimers: Differ at only one stereocenter
- Diasteromers
- Differ at more than one site
- CHO on top and OH to the side
- Ketone carbon is always anomeric carbon
- In ring form, anomeric carbon is bonded to 2 O, 1 C, 1 H
- need to draw glucose, fructose, ribose
4
Q
Ketoses
A
- CH2OH on top and ketone to the side
- Ketone carbon is always anomeric carbon
- In ring form, anomeric carbon is bonded to 2 O, 2 C
5
Q
Reaction of Monosaccharides
A
- Cyclization reactions: Aldehyde + Alcohol makes a hemiacetal
- Ketone + Alcohol makes a hemiketal
6
Q
Anomers
A
- Specific type of epimer that occurs in sugars
- a is down, b is up
- When the stereochem is the same at the anomeric carbon and the stereocenter furthest from the anomeric carbon, it is the b anomer, otherwise the a anomer
7
Q
Pyranose
A
6 membered ring
8
Q
Furanose
A
5 membered ring
9
Q
Reactions of monosaccharides
A
- The linear aldehydes can be readily oxidized to a carboxylic acid
- Sugars with a free aldehyde are called reducing sugars
- Sugars can bereduced to sugar alcohols
- Sugars can be oxidized to acids
10
Q
Glycosidic Bonds
A
- The anomeric carbon-OH can condense with another alcohol to form a glycosidic bond
- Glycosides can no longer open and the stereochemistry of the anomeric carbon is fixed and the compound is no longer a reducing sugar
11
Q
Polymers of Glucose - Glycogen
A
- Stored in granules within cells
- Deposited in the liver, which acts as a central energy storage organ in many animals
- Also abundant in muscle tissue, where it is more immediately available for energy release
- Storage polysaccharide
12
Q
Polymers of Glucose - Amylose
A
- Unbranched Polymer
- Glucose a(1,4) linkage
- Linear component of starch
- Storage polysaccharide
13
Q
Polymers of Glucose - Amylopectin
A
- Branched Polymer
- Glucose a(1,4) linkage with a(1,6) branches
- Component of starch
- Storage Polysaccharide
14
Q
Polymers of Glucose - Cellulose
A
- Structural polysaccharide
- A linear polymer with B(1,4) between monomers
15
Q
Other Polymers
A
- Chitin is the major component of arthropod exoskeletons
- B(1,4) linkages in glucose polymers give structural polysaccharides and a(1,4) give storage polysaccharides
16
Q
Glycosaminoglycans
A
- Charged unbranched polymers of modified sugars
- Very expensive face creams, cartilage and connective tissue, skin, bone, hair, nails
17
Q
Glycoproteins
A
- cell surface and soluble
- N-linked and O-linked oligosaccharides
- N-linked to ASN, O-linked to SER and THR
