Biochem Carbs Lecture 1 Flashcards
Sugars, starches, and cellulose are common
These are dietary staples
This is found in the cell walls of plants and has a structural role
Carbohydrates
Sugars and starch
Cellulose
What is the general formula for carbohydrates?
Cn(H2O)m where n greater than or equal to 3
Name the 2 categories of carbohydrates
Some also contain these 3 elements
Polyhydroxy aldehydes or ketones
Nitrogen phosphorous and sulfur
For most simple sugars, m=?
therefore, the empirical formula of simple sugars is
m=n
(CH2O)n
C5H10O5= (CH2O)5 C6H12O6= (CH2O)6
These are the simple sugars, with monomer units of more complex carbohydrates
Whats the most abundant one?
Monosaccharides
d-glucose (dextrose)
Short chains of monosaccharides joined by _______ bonds, like the disaccharide sucrose (table sugar
Glycosidic
Sugar polymers that contain 20+ monosaccharide units, like cellulose
Polysaccharides
Sugars that contain an aldehyde group are
Sugars that contain a keto group are
Aldoses
Ketoses
3,4,5,6,7 carbon sugars
tritose (?), tetrose, pentose, hexose, heptose
Names can be more specific, glucose is an ______ (has an aldehyde carbonyl group and 6 carbons
Aldohexose
D or L is assigned to which carbon?
The penultimate carbon, the chiral carbon furtherst from the carbonyl carbon
The sugars with the boxes around their names in the handout are the most common in nature. They are all in __ form
D form
These are the two most common simple sugars in nature
D-glucose D-fructose
D-ribose and 2-deoxy-ribose are components of ___
Nucleic acids
Compounds among the D-aldoses and D ketoses corresponding to the same number of atoms are _____ of each other
Diasteriomers (non mirror images)
There are ______ stereoisomers where n = number of chiral centers
2^n
The aldohexoses have how many carbon centers?
Therefore, how many stereoisomers do they have?
4
16 (2^4)
In aqueous solution, aldotetroses and all monosaccharides with 5 or more carbon atoms occur predominately as ___ structures
Cyclic
In the formation of the cyclic structures of carbohydrates, the ring structures form as a result of a general reaction between alcohols and aldehydes or ketones to form ___ and ____
Hemiacetal, kemiketal
Does hemiacetal/hemiketal formation create a new chiral center?
Yes.