Carbohydrate_Properties_Flashcards
What is the general formula for monosaccharides?
(CH₂O)ₙ, where n is typically 3-7.
Which functional groups are found in monosaccharides?
Aldehyde (aldoses) or ketone (ketoses).
Why are monosaccharides considered reducing sugars?
They can donate electrons in reactions.
What structural feature of monosaccharides allows chirality?
Asymmetric carbon centers in monosaccharides with more than three carbons.
What forms do monosaccharides commonly exist in?
Linear (open-chain) and cyclic (ring) forms.
Why are cyclic forms of monosaccharides more common in biological systems?
Cyclic forms are more stable.
What are stereoisomers in the context of monosaccharides?
Molecules with the same molecular formula but different spatial arrangements.
In monosaccharides, what is the D-form based on?
Configuration of the chiral center farthest from the carbonyl group.
Define epimers in monosaccharides.
Stereoisomers differing at only one chiral carbon.
Give an example of two monosaccharides that are epimers.
Glucose and galactose (differ at C-4).
What is an anomer in a cyclic monosaccharide?
An isomer at the anomeric carbon, with α- or β-configuration.
Describe the α-anomer configuration in monosaccharides.
The -OH on the anomeric carbon is opposite the CH₂OH group.
Describe the β-anomer configuration in monosaccharides.
The -OH on the anomeric carbon is on the same side as the CH₂OH group.
What bond connects two monosaccharides in a disaccharide?
Glycosidic bond.
How are glycosidic bonds specified?
By the α- or β-configuration and the carbons involved (e.g., α(1→4)).
What makes a disaccharide a reducing sugar?
It has a free anomeric carbon.
Why is sucrose a nonreducing sugar?
Both anomeric carbons are involved in the glycosidic bond.
What monosaccharides make up maltose, and how are they bonded?
Two glucose units with an α(1→4) bond.
Which disaccharide consists of glucose and galactose with a β(1→4) bond?
Lactose.
Which monosaccharides form sucrose, and what bond connects them?
Glucose and fructose with an α(1→β2) bond.
What are homopolysaccharides?
Polysaccharides made of one type of monosaccharide.
Give an example of a homopolysaccharide.
Starch, glycogen, or cellulose.
What are heteropolysaccharides?
Polysaccharides composed of different types of monosaccharides.
Name a heteropolysaccharide found in connective tissue.
Glycosaminoglycans (GAGs).
What type of linkages are found in energy storage polysaccharides?
α-linkages (e.g., in starch and glycogen).
What type of linkages are characteristic of structural polysaccharides?
β-linkages (e.g., in cellulose and chitin).
Why are branched polysaccharides like glycogen efficient for fuel storage?
They allow rapid glucose release due to multiple nonreducing ends.
What role does cellulose play in plants?
Provides structural support.
How do β(1→4) linkages in cellulose affect its structure?
They form linear, strong fibers resistant to digestion.
What is the primary function of glycogen in animals?
Storage of glucose.
How do glycoproteins contribute to cell recognition?
They participate in cell signaling and communication.
What is the role of proteoglycans in the extracellular matrix (ECM)?
They aid in cell adhesion and interact with ECM components.
Which carbohydrate-containing lipids are important in immune response?
Glycolipids and glycosphingolipids.
What function do selectins and lectins serve in the body?
Mediate cell-cell adhesion, important in immune response.
What polysaccharide provides structural support in fungi and insects?
Chitin.
