PORTAGE LEARNING CHEM 210 MODULE 4 PROBLEM
SET QUESTIONS WITH ANSWERS AND EXPLANATIONS
Question 1.
Which cyclic functional group is formed when a ketose closes to a ring?
A. Anhydride
B. Hemiacetal
C. Peptide
D. Hemiketal
Correct Answer: D. Hemiketal
Explanation: Hemiketal matches the carbohydrate structure or linkage described in the
stem. The distractors differ in carbonyl type, stereochemical relationship, linkage
geometry, or biologic function. Careful tracking of the anomeric carbon and glycosidic
bond is central to Module 4 problem solving.
Question 2.
A laboratory observation shows that it is useful for identifying alpha and beta anomers.
Which concept best explains this finding?
A. Triose
B. Hemiketal
C. Haworth projection
D. Enantiomers
Correct Answer: C. Haworth projection
Explanation: Haworth projection best explains the observation because a Haworth
projection is a simplified representation of a cyclic sugar ring showing substituents above
or below the ring plane. The clue in the stem points directly to this mechanism or
structural feature. The other options involve different biochemical properties and therefore
do not account for the observation as well.
Question 3.
Which choice correctly names the following description: Galactose is an aldohexose that is
the C-4 epimer of glucose.
A. Galactose
B. Hexose
C. Reducing sugar
D. Polysaccharide
Correct Answer: A. Galactose
Explanation: Galactose is defined by this description. The key identifying feature is that it
is a component of lactose. The other choices refer to distinct concepts within carbohydrate
structure, stereochemistry, cyclic forms, glycosidic linkages, and polysaccharide function
and do not match all parts of the description.
,Question 4.
A laboratory observation shows that cyclic glucose contains a hemiacetal at its anomeric
carbon. Which concept best explains this finding?
A. Carbohydrate
B. Hemiacetal
C. Triose
D. Beta glycosidic linkage
Correct Answer: B. Hemiacetal
Explanation: Hemiacetal best explains the observation because a hemiacetal forms when
an aldehyde reacts intramolecularly with an alcohol during aldose ring closure. The clue in
the stem points directly to this mechanism or structural feature. The other options involve
different biochemical properties and therefore do not account for the observation as well.
Question 5.
Which pairing in this set correctly associates a biochemical term with its definition? Focus
on the set built around Deoxyribose.
A. Chitin - A reducing sugar has a free anomeric carbon that can access an open-chain
carbonyl form and reduce mild oxidizing agents.
B. Glycogen - Chitin is a structural polysaccharide composed mainly of beta(1->4)-linked
N-acetylglucosamine residues.
C. Reducing sugar - Glycogen is a highly branched animal storage polysaccharide of
glucose.
D. Deoxyribose - 2-deoxyribose is the pentose sugar of DNA and lacks the 2-prime
hydroxyl group present in ribose.
Correct Answer: D. Deoxyribose - 2-deoxyribose is the pentose sugar of DNA and
lacks the 2-prime hydroxyl group present in ribose.
Explanation: The correct pairing is Deoxyribose with its defining description. Each
distractor deliberately pairs a valid biochemical term with the definition of a different
concept. Matching vocabulary to mechanism is essential before applying the ideas to
calculations or molecular examples.
Question 6.
A laboratory observation shows that its cyclic pyranose form predominates in aqueous
solution. Which concept best explains this finding?
A. Beta glycosidic linkage
B. Carbohydrate
C. Glucose
D. Monosaccharide
Correct Answer: C. Glucose
,Explanation: Glucose best explains the observation because glucose is an aldohexose
and a central metabolic fuel. The clue in the stem points directly to this mechanism or
structural feature. The other options involve different biochemical properties and therefore
do not account for the observation as well.
Question 7.
What is the main role of cellulose in plants?
A. Structural support in cell walls
B. Rapid animal glucose storage
C. Steroid hormone synthesis
D. Oxygen transport
Correct Answer: A. Structural support in cell walls
Explanation: Structural support in cell walls matches the carbohydrate structure or
linkage described in the stem. The distractors differ in carbonyl type, stereochemical
relationship, linkage geometry, or biologic function. Careful tracking of the anomeric
carbon and glycosidic bond is central to Module 4 problem solving.
Question 8.
A laboratory observation shows that glucose and fructose are monosaccharides. Which
concept best explains this finding?
A. Glucose
B. Monosaccharide
C. Glycosidic bond
D. Alpha glycosidic linkage
Correct Answer: B. Monosaccharide
Explanation: Monosaccharide best explains the observation because a monosaccharide is
a single carbohydrate unit that cannot be hydrolyzed to a simpler carbohydrate. The clue
in the stem points directly to this mechanism or structural feature. The other options
involve different biochemical properties and therefore do not account for the observation
as well.
Question 9.
Why can humans digest starch more readily than cellulose?
A. Starch contains peptide bonds
B. Cellulose contains no glucose
C. Cellulose is a lipid
D. Human enzymes hydrolyze alpha-linked glucose polymers but not cellulose beta(1->4)
linkages
Correct Answer: D. Human enzymes hydrolyze alpha-linked glucose polymers
but not cellulose beta(1->4) linkages
, Explanation: Human enzymes hydrolyze alpha-linked glucose polymers but not cellulose
beta(1->4) linkages matches the carbohydrate structure or linkage described in the stem.
The distractors differ in carbonyl type, stereochemical relationship, linkage geometry, or
biologic function. Careful tracking of the anomeric carbon and glycosidic bond is central to
Module 4 problem solving.
Question 10.
A laboratory observation shows that starch, glycogen, cellulose, and chitin are
polysaccharides. Which concept best explains this finding?
A. Polysaccharide
B. Glucose
C. D configuration
D. L configuration
Correct Answer: A. Polysaccharide
Explanation: Polysaccharide best explains the observation because a polysaccharide is a
polymer containing many monosaccharide residues. The clue in the stem points directly to
this mechanism or structural feature. The other options involve different biochemical
properties and therefore do not account for the observation as well.
Question 11.
Consider the following description. Which term matches the following description: A
Haworth projection is a simplified representation of a cyclic sugar ring showing
substituents above or below the ring plane.
A. Hemiketal
B. Triose
C. Haworth projection
D. Enantiomers
Correct Answer: C. Haworth projection
Explanation: Haworth projection is defined by this description. The key identifying
feature is that it is useful for identifying alpha and beta anomers. The other choices refer
to distinct concepts within carbohydrate structure, stereochemistry, cyclic forms,
glycosidic linkages, and polysaccharide function and do not match all parts of the
description.
Question 12.
A laboratory observation shows that glucose and galactose are epimers at C-4. Which
concept best explains this finding?
A. Mutarotation
B. Epimers
C. Amylose
D. Aldose
Correct Answer: B. Epimers
SET QUESTIONS WITH ANSWERS AND EXPLANATIONS
Question 1.
Which cyclic functional group is formed when a ketose closes to a ring?
A. Anhydride
B. Hemiacetal
C. Peptide
D. Hemiketal
Correct Answer: D. Hemiketal
Explanation: Hemiketal matches the carbohydrate structure or linkage described in the
stem. The distractors differ in carbonyl type, stereochemical relationship, linkage
geometry, or biologic function. Careful tracking of the anomeric carbon and glycosidic
bond is central to Module 4 problem solving.
Question 2.
A laboratory observation shows that it is useful for identifying alpha and beta anomers.
Which concept best explains this finding?
A. Triose
B. Hemiketal
C. Haworth projection
D. Enantiomers
Correct Answer: C. Haworth projection
Explanation: Haworth projection best explains the observation because a Haworth
projection is a simplified representation of a cyclic sugar ring showing substituents above
or below the ring plane. The clue in the stem points directly to this mechanism or
structural feature. The other options involve different biochemical properties and therefore
do not account for the observation as well.
Question 3.
Which choice correctly names the following description: Galactose is an aldohexose that is
the C-4 epimer of glucose.
A. Galactose
B. Hexose
C. Reducing sugar
D. Polysaccharide
Correct Answer: A. Galactose
Explanation: Galactose is defined by this description. The key identifying feature is that it
is a component of lactose. The other choices refer to distinct concepts within carbohydrate
structure, stereochemistry, cyclic forms, glycosidic linkages, and polysaccharide function
and do not match all parts of the description.
,Question 4.
A laboratory observation shows that cyclic glucose contains a hemiacetal at its anomeric
carbon. Which concept best explains this finding?
A. Carbohydrate
B. Hemiacetal
C. Triose
D. Beta glycosidic linkage
Correct Answer: B. Hemiacetal
Explanation: Hemiacetal best explains the observation because a hemiacetal forms when
an aldehyde reacts intramolecularly with an alcohol during aldose ring closure. The clue in
the stem points directly to this mechanism or structural feature. The other options involve
different biochemical properties and therefore do not account for the observation as well.
Question 5.
Which pairing in this set correctly associates a biochemical term with its definition? Focus
on the set built around Deoxyribose.
A. Chitin - A reducing sugar has a free anomeric carbon that can access an open-chain
carbonyl form and reduce mild oxidizing agents.
B. Glycogen - Chitin is a structural polysaccharide composed mainly of beta(1->4)-linked
N-acetylglucosamine residues.
C. Reducing sugar - Glycogen is a highly branched animal storage polysaccharide of
glucose.
D. Deoxyribose - 2-deoxyribose is the pentose sugar of DNA and lacks the 2-prime
hydroxyl group present in ribose.
Correct Answer: D. Deoxyribose - 2-deoxyribose is the pentose sugar of DNA and
lacks the 2-prime hydroxyl group present in ribose.
Explanation: The correct pairing is Deoxyribose with its defining description. Each
distractor deliberately pairs a valid biochemical term with the definition of a different
concept. Matching vocabulary to mechanism is essential before applying the ideas to
calculations or molecular examples.
Question 6.
A laboratory observation shows that its cyclic pyranose form predominates in aqueous
solution. Which concept best explains this finding?
A. Beta glycosidic linkage
B. Carbohydrate
C. Glucose
D. Monosaccharide
Correct Answer: C. Glucose
,Explanation: Glucose best explains the observation because glucose is an aldohexose
and a central metabolic fuel. The clue in the stem points directly to this mechanism or
structural feature. The other options involve different biochemical properties and therefore
do not account for the observation as well.
Question 7.
What is the main role of cellulose in plants?
A. Structural support in cell walls
B. Rapid animal glucose storage
C. Steroid hormone synthesis
D. Oxygen transport
Correct Answer: A. Structural support in cell walls
Explanation: Structural support in cell walls matches the carbohydrate structure or
linkage described in the stem. The distractors differ in carbonyl type, stereochemical
relationship, linkage geometry, or biologic function. Careful tracking of the anomeric
carbon and glycosidic bond is central to Module 4 problem solving.
Question 8.
A laboratory observation shows that glucose and fructose are monosaccharides. Which
concept best explains this finding?
A. Glucose
B. Monosaccharide
C. Glycosidic bond
D. Alpha glycosidic linkage
Correct Answer: B. Monosaccharide
Explanation: Monosaccharide best explains the observation because a monosaccharide is
a single carbohydrate unit that cannot be hydrolyzed to a simpler carbohydrate. The clue
in the stem points directly to this mechanism or structural feature. The other options
involve different biochemical properties and therefore do not account for the observation
as well.
Question 9.
Why can humans digest starch more readily than cellulose?
A. Starch contains peptide bonds
B. Cellulose contains no glucose
C. Cellulose is a lipid
D. Human enzymes hydrolyze alpha-linked glucose polymers but not cellulose beta(1->4)
linkages
Correct Answer: D. Human enzymes hydrolyze alpha-linked glucose polymers
but not cellulose beta(1->4) linkages
, Explanation: Human enzymes hydrolyze alpha-linked glucose polymers but not cellulose
beta(1->4) linkages matches the carbohydrate structure or linkage described in the stem.
The distractors differ in carbonyl type, stereochemical relationship, linkage geometry, or
biologic function. Careful tracking of the anomeric carbon and glycosidic bond is central to
Module 4 problem solving.
Question 10.
A laboratory observation shows that starch, glycogen, cellulose, and chitin are
polysaccharides. Which concept best explains this finding?
A. Polysaccharide
B. Glucose
C. D configuration
D. L configuration
Correct Answer: A. Polysaccharide
Explanation: Polysaccharide best explains the observation because a polysaccharide is a
polymer containing many monosaccharide residues. The clue in the stem points directly to
this mechanism or structural feature. The other options involve different biochemical
properties and therefore do not account for the observation as well.
Question 11.
Consider the following description. Which term matches the following description: A
Haworth projection is a simplified representation of a cyclic sugar ring showing
substituents above or below the ring plane.
A. Hemiketal
B. Triose
C. Haworth projection
D. Enantiomers
Correct Answer: C. Haworth projection
Explanation: Haworth projection is defined by this description. The key identifying
feature is that it is useful for identifying alpha and beta anomers. The other choices refer
to distinct concepts within carbohydrate structure, stereochemistry, cyclic forms,
glycosidic linkages, and polysaccharide function and do not match all parts of the
description.
Question 12.
A laboratory observation shows that glucose and galactose are epimers at C-4. Which
concept best explains this finding?
A. Mutarotation
B. Epimers
C. Amylose
D. Aldose
Correct Answer: B. Epimers
