BCHM-3050 Lecture Notes - Lecture 11: Furanose, Sucrose, Starch
26 Jun 2018
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Chapter 9: Carbohydrates: Sugars, Saccharides and Glycans
Diverse Functions
Metabolism storage, and generation of energy (catabolism)
Molecular/Cellular Recognition
Cellular Protection
Cell adhesion
Biological Lubrication
Maintenance of biological structure
Glossary of Terms
Monosaccharides: simple sugars and have 3-9 carbon atoms (monomers)
Oligosaccharide: compound by forming 2-4 monosaccharides together and held together by a
glycosidic bond.
Polysaccharide: polymer formed from multiple (4+) saccharide units.
oHomo: same saccharides
oHeter: different saccharides
Glycan: generic term for both oligosaccharides and polysaccharide
Formula: (CH2O)n
Monosaccharides
Trioses (n=3):
oGlyceraldehyde (aldose because it contains an aldehyde functional group). It is a CHIRAL
molecule
oDihydroxyacteone (ketose that contains a ketone functional group)
** KNOW THE STRUCTURES**
oFOR SUGARS, WE USE D CHIRALITY
Tetroses (n=4)
oThreose
oErythrose
** ALL CHIRAL CENTERS CAN SWITCH**
Compounds with more than 1 asymmetric carbon, it could be an enantiomers or
diastereomers.
Diastereomers are optical isomers that ARE NOT MIRROR IMAGES
For sugars, D & L refers to the configuration around the asymmetric carbon FARTHEST
FRO MTHE CARBONYL CARBON.
oKeto form of a tetrose is erythrulose, which only has 1 asymmetric carbon
Chirality
R = clockwise
S = counter-clockwise
D = right
L = left
**D & L denotes ALL chiral centers and R & S denote ONLY ONE chiral center.
(+) & (-) denotes the optical rotation for a specific stereoisomer
Stereochemical Relationships
Enantiomers: optical isomers that are mirror images
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Metabolism storage, and generation of energy (catabolism) Monosaccharides: simple sugars and have 3-9 carbon atoms (monomers) Oligosaccharide: compound by forming 2-4 monosaccharides together and held together by a glycosidic bond. Polysaccharide: polymer formed from multiple (4+) saccharide units: homo: same saccharides, heter: different saccharides. Glycan: generic term for both oligosaccharides and polysaccharide. Trioses (n=3): glyceraldehyde (aldose because it contains an aldehyde functional group). It is a chiral molecule: dihydroxyacteone (ketose that contains a ketone functional group) ** know the structures*: for sugars, we use d chirality. Compounds with more than 1 asymmetric carbon, it could be an enantiomers or diastereomers. Diastereomers are optical isomers that are not mirror images. For sugars, d & l refers to the configuration around the asymmetric carbon farthest. Fro mthe carbonyl carbon: keto form of a tetrose is erythrulose, which only has 1 asymmetric carbon.
