Chapter 8 Review Flashcards
The most abundant biomolecules on Earth. Central role in energy yielding pathway. Structural element in DNA/RNA. Structural element of cell wall
Carbohydrates
Monosaccharides
(C*H2O)n with n >/= 3
All amino acids have ______-stereochemistry
L
All carbohydrates have _______-stereochemistry.
D
2^n (n is the # of stereocenter carbons)
of stereoisomers
2 kinds of carbohydrates
Aldehydes & Ketones (vary only based on where the carbonyl is)
Alcohol + aldehyde =
hemiacetal
alcohol + ketone =
hemiketal
Linear carbohydrates are not common. Most of the time the ________ is being attacked by the chain’s _______.
ketone ; alcohol
Aldehyde
O
l l
C
/ \
H CKetone
O
ll
C
/ \
R R6-membered ring
Pyran
5-membered ring
Furan
_________ is the only sugar that has all the bulkiest substituents equatorial.
The most stable (and abundant) sugar
Glucose
Oxidation of an aldehyde produces
carboxylic acid
Oxidation of primary alcohols produces
Uronic acids
Reduction of aldehyde produces
alditols
Reduction of alcohols produces
deoxy sugars
Amine substitution of alcohol
Amino sugars
Cellulose is linked via ___ configuration on the anomeric carbon
β
α-amylose is linked via ___ configuration. α-amylose is also irregularly aggregating ________ coiled configuration.
α ; helically
Glycosaminoglycans are
Repeating Disaccharide Units
_____- amino acids occur in the bacterial cell walls.
L
Proteoglycan (Bottle Brush)
Protein connected to glycan
Why would a protein want to be connected to a polysaccharide?
- Adds flexibility
- Communication between units
- Sample space
- Important for antibodies (antigen is found on the outside of the cell)
What proteins are modified by polysaccharides?
Cell membrane proteins
D-configuration means
OH group is on the right
L-configuration means
OH group is on the left
Epimers
Sugars that differ only by the configuration around one C atom.
Enantiomers
molecules that are nonsuperimposable mirror images of one another. A type of stereoisomer.
Diastereomers
members of each pair of enantiomers
Anomers
Sugars that differ only in the configuration around the anomeric carbon.
β anomer
OH substituent is on the same side
α anomer
OH is on the opposite side of the ring from CH2OH group at the chiral center that designates the D or L configuration.
Anomeric Carbon
Carbon #1 with OH group. This is where the nitrogen base attacks. CH2OH is the 5’ carbon.
