BICH 409: EXAM 3 REVIEW UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
Question:
1. what is a carbohydrate
Answer:
organic molecules composed of C, H, and O, usually in the ratio Cₙ(H₂O)ₙ.
Question:
2. What are the major roles of carbohydrates in nature?
Answer:
-Energy storage: Glucose, starch, glycogen
-Structural: Cellulose (plants), chitin (insects, fungi)
-Cell recognition and signaling: Glycoproteins, glycolipids
-Metabolic intermediates: Ribose in nucleotides (DNA/RNA), glucose-6-
phosphate in glycolysis
Question:
3. How to classify monosaccharides by the carbonyl carbon
Answer:
Aldose: contains an aldehyde (-CHO)
Ketose: contains a ketone (C=O)
Question:
4. How to classify monosaccharides by the number of
carbons?
Answer:
3C = triose
4C = tetrose
5C = pentose
6C = hexose
7C = heptose
Question:
5. How to distinguish D from L sugars?
Answer:
Look at the chiral carbon farthest from the carbonyl in the Fischer projection:
-OH on the right → D-sugar
-OH on the left → L-sugar
,Question:
6. What is the abreviation of ribose
Answer:
rib
Question:
7. What is the abreviation of arabinose
Answer:
Ara
Question:
8. What is the abreviation of Xylose
Answer:
Xyl
Question:
9. What is the abreviation of Lyxose
Answer:
Lyx
Question:
10. What is the abreviation of Allose
Answer:
All
Question:
11. What is the abreviation of Glucose
Answer:
Glc
Question:
12. What is the abreviation of Mannose
Answer:
Man
Question:
13. What is the abreviation of Galactose
Answer:
Gal
, Question:
14. What is the abreviation of Idose
Answer:
Ido
Question:
15. D-Arabinose is a C2 epimer of which aldose
Answer:
Ribose
Question:
16. D-Xylose is a C3 epimer of which aldose
Answer:
Ribose
Question:
17. D-Lyxose is a C3 epimer of which aldose
Answer:
Arabinose
Question:
18. Which aldoses are hexoses
Answer:
-D Allose
-D Glucose
-D Mannose
-D Idose
-D Galactose
Question:
19. Which aldose is a triose
Answer:
D-Glyceraldehyde
Question:
20. Which aldoses are a tetrose
Answer:
-D Erythrose
-D Threose
QUESTIONS AND CORRECT ANSWERS
Question:
1. what is a carbohydrate
Answer:
organic molecules composed of C, H, and O, usually in the ratio Cₙ(H₂O)ₙ.
Question:
2. What are the major roles of carbohydrates in nature?
Answer:
-Energy storage: Glucose, starch, glycogen
-Structural: Cellulose (plants), chitin (insects, fungi)
-Cell recognition and signaling: Glycoproteins, glycolipids
-Metabolic intermediates: Ribose in nucleotides (DNA/RNA), glucose-6-
phosphate in glycolysis
Question:
3. How to classify monosaccharides by the carbonyl carbon
Answer:
Aldose: contains an aldehyde (-CHO)
Ketose: contains a ketone (C=O)
Question:
4. How to classify monosaccharides by the number of
carbons?
Answer:
3C = triose
4C = tetrose
5C = pentose
6C = hexose
7C = heptose
Question:
5. How to distinguish D from L sugars?
Answer:
Look at the chiral carbon farthest from the carbonyl in the Fischer projection:
-OH on the right → D-sugar
-OH on the left → L-sugar
,Question:
6. What is the abreviation of ribose
Answer:
rib
Question:
7. What is the abreviation of arabinose
Answer:
Ara
Question:
8. What is the abreviation of Xylose
Answer:
Xyl
Question:
9. What is the abreviation of Lyxose
Answer:
Lyx
Question:
10. What is the abreviation of Allose
Answer:
All
Question:
11. What is the abreviation of Glucose
Answer:
Glc
Question:
12. What is the abreviation of Mannose
Answer:
Man
Question:
13. What is the abreviation of Galactose
Answer:
Gal
, Question:
14. What is the abreviation of Idose
Answer:
Ido
Question:
15. D-Arabinose is a C2 epimer of which aldose
Answer:
Ribose
Question:
16. D-Xylose is a C3 epimer of which aldose
Answer:
Ribose
Question:
17. D-Lyxose is a C3 epimer of which aldose
Answer:
Arabinose
Question:
18. Which aldoses are hexoses
Answer:
-D Allose
-D Glucose
-D Mannose
-D Idose
-D Galactose
Question:
19. Which aldose is a triose
Answer:
D-Glyceraldehyde
Question:
20. Which aldoses are a tetrose
Answer:
-D Erythrose
-D Threose
