Carbohydrates Flashcards
(25 cards)
What is a carbohydrate?
A compound of carbon and water; the most common biomolecule, used for energy, storage, and structural roles.
What are Lewis structures?
Straight-line covalent bond diagrams with dots for unpaired electrons.
What is a Fischer projection?
A simple way to depict isomers, commonly used for carbohydrates.
What is a Haworth projection?
A 3D-like projection useful for visualizing carbohydrates in ring form.
What is a chair conformation?
A model showing the actual spatial structure of a molecule; more detailed but can be confusing.
How are carbohydrates named by carbon number?
3 C → Triose
4 C → Tetrose
5 C → Pentose
6 C → Hexose
How are carbohydrates named by functional group?
Aldehyde → Aldose
Ketone → Ketose
Example of aldohexose and ketohexose?
Aldohexose → Glucose
Ketohexose → Fructose
What does the suffix “-ose” mean?
It indicates a sugar.
What are enantiomers?
Isomers that are mirror images.
What are diastereomers?
Isomers with more than one chiral center that are not mirror images.
What are epimers?
Isomers differing at only one chiral center.
Example of D- and L- configurations?
D-tetrose (with aldehyde group, 4 C, 2 chiral centers → 4 stereoisomers) has D- and L- forms as enantiomers.
How many stereoisomers for a sugar with 4 chiral centers?
16 stereoisomers (8 D, 8 L; 8 enantiomer pairs).
What increases carbohydrate stability?
Cyclization:
6-membered ring → pyranose
5-membered ring → furanose
What are anomers?
Cyclic monosaccharide epimers that differ at the anomeric carbon.
What’s the difference between α and β anomers?
α (alpha): OH on anomeric C opposite side of O (trans)
β (beta): OH on anomeric C same side as O (cis)
What type of reaction forms a glycosidic bond?
A condensation reaction (dehydration reaction).
What are examples of disaccharides?
Maltose = glucose + glucose
Lactose = glucose + galactose
Sucrose = glucose + fructose
What is the most abundant organic compound?
Cellulose.
Why does the body store glucose as glycogen?
Because glycogen is insoluble in water, making it a compact, efficient storage form.
What is the base unit of chitin?
N-acetyl-β-D-glucosamine.
How can carbohydrates be chemically modified?
By redox reactions or addition of functional groups (e.g., phosphate, amino, N-acetyl).
What is the general formula of carbohydrates?
(CH2O)n
