Carbs 1 Flashcards
What are carbs
Simple
And
Complex
Carbon based molecules that have many OH groups
Simple carbs are monosaccharides (one sugar)
Complex are polysaccharide (many sugars, covlently linked monosaccharides
What are carbs used for
Energy storage
cellular recognition
Structure (ex. Exoskeleton of insects)
What is the empirical formula of carbs
(Ch2O)n
N=3 trios
N= 4 tetros
In a Fischer projection what points out in and in
Looked from the side of the molecule,
Horizontal bonds are out
Verticals bonds are in
What are monosaccharides
What are the simplest monosaccharides
Aldehydes or ketones with two or more OH groups These are called aldoses or ketoses
The simplest have three carbons (trioses)
What is a ketose
The simplest ketoses name
Ketoses if a monosaccharide with a ketone group
Called dihydroxyacetone (two OH)
What is a aldose
What could it be named
A monosaccharide with and aldehyde group
Can be named D or L glyceraldehyde
What determines the D/L of an aldose
If the oh on the chiral centre furthest from the Aldehyde is on the left it’s L
If on right it’s D
Constitutional isomers
Same formula diff attachment of atoms
Ex. Glyceraldehyde and dihydroxyacetone
Stereoisomer are
Same formula and order of attachement but different spatial arrangement
What are enantiomers
Disasteriomer
Non super impossible mirror images (are mirrors and can’t be superimposed, all chiral centre changed)
Isomers that aren’t mirror images (1 or more chiral centres change)
What is included in diasteriomers
Epimers or anomers
What is an epimer
The chirality is different only at one of the chiral carbons (rest is the same)
Ex. D glucose and D mannose
We call them epimeric at C2
What is an anomer
The diasteriomers differ at a new assymetric carbon (the anomeric carbon) formed during the closure of the ring
Alpha if the OH is down
Beta if the OH is up
Are all diasteriomers epimers or anomers
No some differ at more than one chiral centre
So these ones arent
How does ring closure of a monosaccharide aldose happen
The alchohol (ROH) attacked the aldehydes c=o
The c=o turns to coh and the alchohol is attached and becomes coR
Forms hemiacetal
What is a six members ring called
What about 5
Pyran
Furan
In an aldose (d glucose) which carbon attacks the aldehyde
The 5th one to give a six members ring (o in the ring makes 6)
Give alpha or beta d glucopyranose
Pyranose for the 6 membred ring
PRACTICE DRAWING RING CLOSURES
okay
What potion of d gluco pyranose is in the alpha and beta
Alpha 1/3
Beta 2/3
What conformation of d glucopyranose is most favours
Chair less steric hindrance because the axial components aren’t as much on the same side of the ring
Equatorial are also more spread out
If alpha the oh is
If beta the oh is
Axial
Equatorial
In ketoses how is the ring formed
The alcohol reacts with the ketone to form hemiketal
How do we name the 5 membered ring of fructose
Can the 6 members ring be made
Alpha or beta d fructofuranose
Yes is c6 attacks instead of c5
For fructose (ketose) what form dominates when free in solution
What about in many fructose derivatives
Pyranose (6)
Furanose (5)
Learn structures of
The ketose hexose d fructose
The aldoses :
Pentose D ribose
Hexose d glucose d galactose d mannose
