CHEM 210 Module 4 Exam Portage
Learning | 50 Comprehensive Q&As with
Detailed Rationales (Carbohydrates &
Biochemistry Prep)
overveiw
To excel on the CHEM 210 Biochemistry Module 4 Exam through Portage Learning, you
need a firm grasp of Carbohydrate Chemistry. This module covers the classification,
structural properties, and functions of monosaccharides, disaccharides, and
polysaccharides.
The highest-yield concepts, actual exam-style questions, and detailed rationales are
detailed below:
Core Conceptual Breakdown
Aldoses vs. Ketoses: Aldoses contain an aldehyde functional group (typically at the
C1 terminal carbon), such as glucose, galactose, and glyceraldehyde. Ketoses
contain a ketone functional group (typically at the C2 carbon), with
dihydroxyacetone and fructose being classic examples.
D vs. L Designation: Determined by looking at the penultimate carbon (the
second-to-last carbon in the Fischer projection). If the hydroxyl (−OH) group on this
carbon is on the right, the sugar is a D-isomer. If it is on the left, it is an L-isomer.
, Epimers: Two monosaccharides that differ only in the stereochemical configuration
about a single asymmetric carbon atom (e.g., D-glucose and D-galactose are C-4
epimers).
Anomers: Isomers that differ only in configuration at the hemiacetal or hemiketal
carbon (the anomeric carbon, which becomes chiral during ring closure). Example:
α-D-glucose and β-D-glucose.
Glycosidic Bond Formation: When two monosaccharides undergo a condensation
reaction to form a disaccharide, water is released (H2O), forming a covalent
glycosidic linkage.
1. Which of the following organic compounds does not fit the formal empirical formula
or chemical definition of a classic carbohydrate molecule?
o A) $C_6H_{12}O_6$
o B) $C_7H{10}O_7$_
o C) $C_5H_{10}O_5$
o D) $C_3H_6O_3$
o E) $C_{12}H_{22}O_{11}$
Carbohydrates typically adhere to the empirical formula $C_n(H_2O)_n$. The formula
$C_7H_{10}O_7$ does not have the expected two-to-one ratio of hydrogen to oxygen,
meaning it does not fit the structural criteria of a carbohydrate.
2. Which of the following simple monosaccharides is structurally classified as a ketose
rather than an aldose?
o A) Erythrose
, o B) Galactose
o C) Glucose
o D) Dihydroxyacetone
o E) Glyceraldehyde
Dihydroxyacetone contains a ketone functional group at its central carbon atom, which
makes it a ketose, whereas the other options all contain terminal aldehyde functional
groups.
3. When comparing two distinct monosaccharide isomers that are classified as
epimers, which of the following statements is true?
o A) They differ in their molecular backbone length by exactly one carbon atom.
o B) One is a pyranose ring structure while the other is a furanose ring
structure.
o C) They differ only in the stereochemical configuration about one single
carbon atom.
o D) One is an aldose sugar while the other is a ketose sugar.
o E) They react completely differently when exposed to an iodine solution.
Epimers are diastereomers that possess multiple chiral centers but differ in their
stereochemical configuration at only a single asymmetric carbon atom.
4. Which of the following pairs of carbohydrates represents anomers of each other in
aqueous solution?
o A) D-glucose and D-fructose
o B) D-glucose and L-glucose
Learning | 50 Comprehensive Q&As with
Detailed Rationales (Carbohydrates &
Biochemistry Prep)
overveiw
To excel on the CHEM 210 Biochemistry Module 4 Exam through Portage Learning, you
need a firm grasp of Carbohydrate Chemistry. This module covers the classification,
structural properties, and functions of monosaccharides, disaccharides, and
polysaccharides.
The highest-yield concepts, actual exam-style questions, and detailed rationales are
detailed below:
Core Conceptual Breakdown
Aldoses vs. Ketoses: Aldoses contain an aldehyde functional group (typically at the
C1 terminal carbon), such as glucose, galactose, and glyceraldehyde. Ketoses
contain a ketone functional group (typically at the C2 carbon), with
dihydroxyacetone and fructose being classic examples.
D vs. L Designation: Determined by looking at the penultimate carbon (the
second-to-last carbon in the Fischer projection). If the hydroxyl (−OH) group on this
carbon is on the right, the sugar is a D-isomer. If it is on the left, it is an L-isomer.
, Epimers: Two monosaccharides that differ only in the stereochemical configuration
about a single asymmetric carbon atom (e.g., D-glucose and D-galactose are C-4
epimers).
Anomers: Isomers that differ only in configuration at the hemiacetal or hemiketal
carbon (the anomeric carbon, which becomes chiral during ring closure). Example:
α-D-glucose and β-D-glucose.
Glycosidic Bond Formation: When two monosaccharides undergo a condensation
reaction to form a disaccharide, water is released (H2O), forming a covalent
glycosidic linkage.
1. Which of the following organic compounds does not fit the formal empirical formula
or chemical definition of a classic carbohydrate molecule?
o A) $C_6H_{12}O_6$
o B) $C_7H{10}O_7$_
o C) $C_5H_{10}O_5$
o D) $C_3H_6O_3$
o E) $C_{12}H_{22}O_{11}$
Carbohydrates typically adhere to the empirical formula $C_n(H_2O)_n$. The formula
$C_7H_{10}O_7$ does not have the expected two-to-one ratio of hydrogen to oxygen,
meaning it does not fit the structural criteria of a carbohydrate.
2. Which of the following simple monosaccharides is structurally classified as a ketose
rather than an aldose?
o A) Erythrose
, o B) Galactose
o C) Glucose
o D) Dihydroxyacetone
o E) Glyceraldehyde
Dihydroxyacetone contains a ketone functional group at its central carbon atom, which
makes it a ketose, whereas the other options all contain terminal aldehyde functional
groups.
3. When comparing two distinct monosaccharide isomers that are classified as
epimers, which of the following statements is true?
o A) They differ in their molecular backbone length by exactly one carbon atom.
o B) One is a pyranose ring structure while the other is a furanose ring
structure.
o C) They differ only in the stereochemical configuration about one single
carbon atom.
o D) One is an aldose sugar while the other is a ketose sugar.
o E) They react completely differently when exposed to an iodine solution.
Epimers are diastereomers that possess multiple chiral centers but differ in their
stereochemical configuration at only a single asymmetric carbon atom.
4. Which of the following pairs of carbohydrates represents anomers of each other in
aqueous solution?
o A) D-glucose and D-fructose
o B) D-glucose and L-glucose
