Carbohydrates Flashcards
What is the glycome?
total sugars produces in a cell or organism
What is a stereoisomer?
two isomers with the same chemical composition but different 3D orientation
A chiral centre is …
generally a carbon with 4 different groups bonded to it with a non-superimposable mirror image
enantiomer:
how many do chiral carbons with one chiral centre have?
- mirror image configurations that aren’t superimposable on each other
- two
epimer:
two sugars that differ only in configuration of one C, require 2+ chiral centres
diastereoisomers:
two monosaccharide stereoisomers with two or more differing chiral carbons that are not mirror images
anomeric carbon:
epimer at the hemiacetyl/acetyl carbon in cyclic form
What is the sugar code?
how sugars inter cellularly code for information
the classes of CHO are ___saccharides (one sugar), ___saccharides (two sugars), ___saccharides (3-10 sugars), and ___saccharides (10+ sugars)
mono/di/oligo/poly
Sugars are either aldoses (prefix ___-) or ketoses (prefix ___-), they have the suffix -___
Aldo/keto/ose
Number of carbons is the middle portion of the name (3=___,4=___,5=___,6=___,7=___)
tri/tetra/penta/hexa/hept
When the aldehyde group is ____ in a Fisher projection it determines the configuration, if the -OH is left its ___ (prefix ___-), of its right its ___ (prefix ___-)
on top/levo/L/dextro/D
number of stereoisomers=2^___, ___=number of ___
n/n/C
enantiomers differ in ___ D/L configuration while epimers differ in ___. Epimers=number of ___-___
every/one/chiral carbons/1
in solution, monosaccharides are mostly found as ___ (aldoses) and ___ (ketoses). aldose+___=___, ketose+___=___
hemiacetyls/hemiketals/alcohol/hemiacetyl/alcohol/hemiketal
Cyclization:
monosaccharides transition from open chain to ring
What is the configuration for α-D-glucopyranose vs. β-D-glucopyranose? when is this difference not visible (in diagram)
- the -OH on the C beside the O is down for α and up for β
- fisher projections
a pyran ring is a ___ membered ring (ex. ___) and a furan is a ___ membered ring (ex.___)
6/glucose/5/fructose
Fehlings reaction: used to determine free ___ levels in ___ or ___ by qualifying sugars with ___ ends. The ___ oxidize in the presence of a strong oxidizing agent and refusing Cu which causes a colour change from ___ to ___. Why is this not completely accurate for measuring blood glucose?
monosaccharide/blood/urine/reducing/blue/red
Not completely accurate because it only detects monosaccharides with reducing ends (includes galactose)
____ provides a good measure of ___-glucose in blood/urine because it’s ___ to glucose, bases on quantification of ____
Glucose oxidase/D/specific/hydrogen peroxide
Disaccharides: ___+___=, ___+___=___, ___+___=___
which have reducing ends?
glucose/glucose/maltose (reducing end)
glucose/galactose/lactose (reducing end)
glucose/fructose/sucrose (no reducing end)
What is a reducing end?
another name for anomeric carbon- can exist in two forms based on substituent position, generated by ring closure of monosaccharides
Polysaccharides are either ___polysaccharides (one monomer) or ___polysaccharides (more than one monomer)
homo/hetero
Starch: mixture of two ___polysacchairdes, made up of ___, used as a storage molecule in ___. Either ___ (branched) or ___ (unbranched)
homo/glucose/plants/amylopectin/amylose
Glycogen: storage molecule in ___. Primarily located in the ___. Main chain is ___ with ___ every 8-12 residues
animals/liver/glucose/branches
___: structural ___polysaccharide, found in the cell wall of plants. Made up of ___, not digestible in humans because of the ___ bonds instead of ___. It is fibrous and water ___.
Cellulose/homo/glucose/β/α/insoluble
Unbranched heteropolysaccharides are present commonly in ___ as a ___
bacteria/coating
Branches heteropolysaccharides are used to link ___ to carbs, making them ___ PRO, ___ PRO, and play a role in folding
PRO/surface/receptor
What are the two types of linked oligosaccharide additions?
N-linked oligosaccharides and O-linked oligosaccharides
Freeness of anomeric carbons in ___saccharides:
maltose: ___ free ___not free (___ total)
lactose: ___ free ___not free (___ total)
trehalose: ___ free ___not free (___ total)
sucrose: ___ free ___not free (___ total)
di 1/1/2 1/1/2 0/2/2 0/1/1
