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1
Question
What are the main compositional differences between monosaccharides, oligosaccharides, and polysaccharides?
Answer
Monosaccharides: one sugar unit; Oligosaccharides: 2-20 units; Polysaccharides: hundreds to thousands of units
2
Question
What structural feature defines aldoses versus ketoses in monosaccharides?
Answer
Aldoses have an aldehyde group; ketoses have a ketone group
3
Question
Why are 5- and 6-carbon monosaccharides most abundant in nature?
Answer
They are key components in nucleic acids and energy metabolism
4
Question
How many stereoisomers exist for aldohexoses like glucose?
Answer
16 stereoisomers (2^4)
5
Question
What determines if a monosaccharide is D or L enantiomer?
Answer
Configuration at the chiral carbon farthest from the carbonyl group
6
Question
What are epimers in monosaccharides?
Answer
Stereoisomers differing at only one chiral center
7
Question
How do monosaccharides with 5 or more carbons typically exist?
Answer
In cyclic structures forming hemiacetals or hemiketals
8
Question
What is the anomeric carbon in cyclic monosaccharides?
Answer
The carbonyl carbon that becomes a new chiral center
9
Question
What distinguishes alpha from beta anomers in glucose?
Answer
Orientation of OH at C1: below (alpha) or above (beta) the ring plane
10
Question
What is mutarotation in monosaccharides?
Answer
Interconversion between alpha and beta anomers in solution
11
Question
Why are sugars with free aldehyde or ketone groups called reducing sugars?
Answer
They can reduce mild oxidizing agents like in Benedict's test
12
Question
How is vitamin C synthesized in most organisms?
Answer
From glucose via enzyme-catalyzed oxidation steps
13
Question
What are sugar alcohols used for industrially?
Answer
Low-calorie sweeteners and anti-cariogenic agents
14
Question
What forms a glycosidic bond between monosaccharides?
Answer
Condensation of anomeric OH with another sugar's OH, losing water
15
Question
What enzyme catalyzes glycosidic bond formation?
Answer
Glycosyltransferase, specific to the donor sugar
16
Question
What are the key functions of oligosaccharides?
Answer
Energy storage, cryoprotection, signaling, and glycoconjugate components
17
Question
What linkage defines lactose as a disaccharide?
Answer
Beta-1,4 linkage between galactose and glucose
18
Question
Why is sucrose a non-reducing sugar?
Answer
Both anomeric carbons are involved in the glycosidic bond
19
Question
What is the role of trehalose in organisms?
Answer
Acts as a cryoprotectant and blood sugar in insects
20
Question
What are prebiotics in the context of oligosaccharides?
Answer
Oligosaccharides that promote growth of beneficial gut bacteria
21
Question
What distinguishes homopolysaccharides from heteropolysaccharides?
Answer
Homopolysaccharides: one sugar type; Heteropolysaccharides: multiple types
22
Question
What structural features make cellulose strong?
Answer
Beta-1,4 linkages and extensive hydrogen bonding between chains
23
Question
Why can't most humans digest cellulose?
Answer
Lack of cellulase enzyme; only ruminants have symbiotic microbes
24
Question
What is chitin's primary function in organisms?
Answer
Structural component in exoskeletons of invertebrates
25
Question
What are alginates composed of?
Answer
Alternating beta-1,4-mannuronic acid and alpha-1,4-guluronic acid
26
Question
How does amylopectin differ from amylose in starch?
Answer
Amylopectin is branched with alpha-1,6 linkages; amylose is linear
27
Question
What enzymes degrade glycogen in animals?
Answer
Glycogen phosphorylase, debranching enzyme, and alpha-glucosidase
28
Question
What defines a glycoconjugate?
Answer
Carbohydrate covalently linked to another biomolecule like protein or lipid
29
Question
What are the main types of glycoconjugates in prokaryotes?
Answer
Glycolipids, lipopolysaccharides (LPS), and peptidoglycans
30
Question
How does LPS function in Gram-negative bacteria?
Answer
Stabilizes membrane and acts as endotoxin triggering immune response