Test #3 Flashcards
(22 cards)
Define Enantiomers
2 compounds whose only difference in physical properties is that they rotate plane polarized light in opposite directions.
What is a Chiral Carbon?
A carbon with 4 different groups attached to it.
What is a racemic mixture?
A mixture that contains equal parts l- and d- enantiomers.
Define Diastereomer.
A carbon compound in which at least one, but not all, chiral carbons are mirrored.
What are Meso compounds?
compounds that are mirror images of one another but are also superimposable, and therefore not enantiomers. (Has a plane of symmetry).
In a Fischer structure, what direction does the Carbonyl point when determining D- or L- orientation?
Up.
Explain how to identify D or L orientation.
With the carbonyl carbon at the top, go to the bottommost chiral carbon and determine whether the OH group is on the left (L) or right (D).
A 3-carbon CHO is called a _____
Triose
A 4-carbon CHO is called a _____
Tetrose
A 5-carbon CHO is called a _____
Pentose.
A 6-carbon CHO is called a _____
Hexose.
The number of stereoisomers for a compound can be determined by what formula?
2^(# of chircal carbons).
Unlike glucose and galactose, fructose is a _____
D-2-Ketohexose
_____ structures form when monosaccharide are in solutions.
Haworth.
The Haworth structure for any monosaccharide forms between the _____ and the _____.
OH on bottommost chiral C and the Carbonyl carbon.
If OH is on left of a Fischer projection, it will point _____ in the Haworth projection.
Up.
True or false: the OH on a C2 carbon can point up or down in the Haworth Structure. Why?
False. It is the C1 carbon that can point up or down.
The _____ carbon determines Alpha or Beta naming.
Anomeric.
For an anomeric carbon, Beta position is when the OH is pointed _____, and Alpha position is when the OH is pointed _____.
Up; Down.
True or false: C5 becomes the anomeric carbon in a Haworth structure. Explain.
False. C1 becomes the anomeric carbon, because it was the carbonyl carbon.
Define Mutarotation.
The process of a monosaccharide naturally interconverting between the alpha, open chain, and beta forms.
How is blood type determined?
Depending on the types of Tri or Tetrasaccharides bound to the surface of the red blood cells.
