1. Carbohydrates Flashcards
(44 cards)
what is a carbohydrate made up of and what is the ratio
contains: carbonyl (C=O) and hydroxyl groups
=aldehydes or ketones with 2 or more hydroxyl groups
ratio of C,H,O is 1:2:1
can carbohydrates be 2C
no at least 3C etc
major classes of carbohydrates (4)
- monosaccharide (simple sugars)
-single aldehyde or ketone with hydroxyl - disaccharide
-2 units of monosaccharides - oligosaccharide
-short chains (3-10) monosaccharides - polysaccharide
-long chains/ more than 10 of monosaccharides
oligosaccharides may be linked to other macromolecules such as _____ and_____
glycoproteins & glycolipids
give 3 functions of carbohydrates
-store energy
-provide energy
-building blocks of macromolecules
-structural elements
-lipid metabolism
how to name monosaccharides based on number of carbons
sugar molecule –> “ose” at end of name
n=3 triose
n=4 tetrose
n=5 pentose
n=6 hexose
n=7 heptose
where do u start numbering carbons
end nearest the carbonyl group (C=O)
for ring: at carbonyl group
aldose vs ketose based on carbonyl
aldose = carbonyl on end (aldehyde)
ketose = carbonyl inside (ketone)
aldoses and ketoses are chiral?
YES - 4 different groups attached
what are constitutional isomers
same composition, different connectivity
how to get stereoisomers
2^power n
n=number of chiral centers
enantiomers vs diastereomers
enantiomers = non superimposable MIRROR images (must have AT LEAST one chiral center)
diastereomers = NOT mirror images ex.cis/trans
compare D and L enantiomers and how are they determined
D-sugars = OH group on the right
L-sugars = OH group on the left
-look at OH on whichever chiral carbon is farthest away from C=O
what is the penultimate carbon
highest numbered chiral carbon
where is carbon 1 drawn on a fischer projection
carbon #1 is always drawn ON TOP
what does it mean to be reduced
gain H (usually breaks C=O to become OH)
when could something no longer be distinguished as D or L sugars
if there is no longer a chiral carbon
what are epimers
-two sugars that differ only in the configuration around ONE CARBON
what are hemiacetals and hemiketals and what is special about their formations
hemiacetals = aldehydes attacked by alcohols
hemiketals = ketones attacked by alcohols
- new hemiacetal/hemiketal carbon becomes CHIRAL
alpha-anomer vs Beta-anomer
alpha - OH opposite C6
beta - OH same as C6
where is anomeric carbon
aldoses is C1
ketoses is C2
result of cyclization / on right side has OH / becomes chiral
what is haworth projection and how to draw
cyclic ring structure
- to the right in fischer projection = are on bottom of ring
-below attacking group (usually OH) = goes on top of ring
what is a furanose vs a pyranose
furanose = 5 membered ring
pyranose = 6 membered ring
which membered ring is more stable
6 membered ring = pyranose
