Ch. 4 Carbohydrates (Exam 1) Flashcards
Monosaccharides (Nomenclature & Ring Formation), Disaccharides (Glycosidic Bond Geometry), Polysaccharides (Linear & Branched), Carbohydrate Derivatives
What is the empirical formula for a carbohydrate?
C(n)H(2n)O(n)
What functional groups do carbs consist of?
Hydroxyls and carbonyls
Are carbs water soluble?
Yes
What are carbs a good source of?
Rapid energy
What is the range of carbons in a monosaccharide?
3-8
Which sugars have aldehyde groups?
Aldoses
Which sugars have ketone groups?
Ketoses
How many carbonyls are in a monosaccharide?
1
What suffix denotes sugar?
-ose
How are monosaccharides named?
Based on number of carbons
What method is used to draw a monosaccharide?
Fischer projection
Which way does the OH group on the penultimate (next to last) carbon face for D stereochemistry?
Right
Which way does the OH group on the penultimate (next to last) carbon face for L stereochemistry?
Left
How do you decide the stereochemistry of a monosaccharide?
The penultimate (next to last) carbon with the OH group determines where stereochemistry will be L or D
Which carbon is the most oxidized?
C1 - the carbonyl/carbon at top of Fischer projection
Do most organisms metabolize L or D sugars?
D sugars
What are epimers?
Epimers are sugars differing at different carbon atoms other than the D or L carbon
What are 5 common types of monosaccharides discussed in the lecture?
1) Erythose
2) Ribose
3) Glucose
4) Galactose
5) Fructose
How many carbons are needed to form a sugar ring?
5 or more
What reactants are needed to form a hemiacetal/hemiketal (HINT: 2 key function groups)?
Carbonyl and hydroxyl (OH)
What is an anomeric carbon, and what does it determine about a cyclic molecule?
The carbon that was the carbonyl in acyclic form and decides whether the sugar is in alpha or beta conformation in cyclic form
How can you determine whether an anomeric carbon is in alpha or beta conformation?
- Alpha: anomeric carbon faces up on same side of ring w/ 6th carbon
- Beta: anomeric carbon faces down on opposite side of ring w/ 6th carbon
What is the key difference between reducing and non-reducing sugars (HINT: something about the anomeric carbon)?
Reducing sugar: free anomeric sugar
Non-reducing sugar: no free anomeric sugar
What are 2 examples of reducing sugars?
1) Maltose
2) Lactose
What are 2 examples of non-reducing sugars?
1) Sucrose
2) Trehalose
How do amylose molecules bond together?
Alpha 1,4 glycosidic bonds
