, CHEM 210 Final Exam - Biochemistry
CHEM 210 final Module Exam | Biochemistry |
Portage Learning | Q & A | 2026/2027 actual
(PDF)
CHEM 210 FINAL EXAM
Biochemistry
Portage Learning
100-Question Practice Examination
2026/2027 Edition
1. A biochemist isolates a cellular structure surrounded by a phospholipid bilayer and containing
its own circular DNA. Which structure is most consistent with these observations?
A) Golgi apparatus
B) Lysosome
C) Mitochondrion
D) Peroxisome
Correct Answer: Mitochondrion
Rationale: Mitochondria are membrane-bound organelles that retain their own circular DNA, reflecting
their endosymbiotic origin. Lysosomes, the Golgi apparatus, and peroxisomes are membrane-bound but
do not contain an independent circular genome. Recognizing structural features helps connect cell
organization with biochemical function.
2. A molecule contains both a carbonyl group and a hydroxyl group on adjacent carbons. Which
conclusion is most reasonable?
A) It must be completely nonpolar
B) It cannot interact with water
C) It can participate in hydrogen bonding and polar reactions
D) It can form only ionic bonds
Correct Answer: It can participate in hydrogen bonding and polar reactions
Rationale: Carbonyl and hydroxyl groups are polar functional groups. The hydroxyl group can donate and
accept hydrogen bonds, while the carbonyl oxygen can accept them, so the molecule can interact
strongly with water and other polar species. The presence of these groups does not require ionic
bonding or complete nonpolarity.
3. Why is carbon especially well suited to form the molecular skeletons of biomolecules?
A) It is the most electronegative element
B) It exists only as an ion in cells
C) It can form four covalent bonds and stable chains or rings
Practice Examination | 2026/2027 Edition | Page 1
, CHEM 210 Final Exam - Biochemistry
D) It readily forms only one bond
Correct Answer: It can form four covalent bonds and stable chains or rings
Rationale: Carbon has four valence electrons and can form four stable covalent bonds, including bonds
to other carbon atoms. This supports chains, branches, rings, and multiple bonds that create biochemical
diversity. Carbon is not the most electronegative element and does not exist only in ionic form in cells.
4. Two molecules have the same molecular formula but different connectivity of their atoms. How
should they be classified?
A) Constitutional isomers
B) Identical molecules
C) Isotopes
D) Enantiomers only
Correct Answer: Constitutional isomers
Rationale: Constitutional isomers share a molecular formula but differ in how atoms are connected.
Isotopes differ in neutron number, while enantiomers specifically require non-superimposable mirror-
image stereochemistry rather than merely different connectivity. Distinguishing isomer types is important
because connectivity can strongly change biochemical reactivity.
5. A reaction in a cell links two small molecules while releasing water. Which reaction type best
describes this process?
A) Condensation reaction
B) Hydrolysis
C) Oxidative phosphorylation
D) Ionization
Correct Answer: Condensation reaction
Rationale: A condensation, or dehydration-synthesis, reaction forms a covalent bond while eliminating
water. Hydrolysis does the opposite by using water to break a bond. Oxidative phosphorylation concerns
ATP generation through an electron-transport-driven proton gradient, and ionization refers to gain or loss
of charged particles such as protons.
6. A protein is synthesized on ribosomes attached to rough endoplasmic reticulum. Which
destination is most plausible for the mature protein?
A) Exclusive use as cytosolic glycolytic enzyme
B) Conversion directly into DNA
C) Secretion from the cell or insertion into a membrane
D) Permanent storage inside the nucleus
Correct Answer: Secretion from the cell or insertion into a membrane
Rationale: Proteins translated on rough-ER-bound ribosomes commonly enter the secretory pathway,
becoming secreted proteins, lysosomal proteins, or membrane proteins. Most cytosolic enzymes are
translated on free ribosomes. Proteins are not directly converted into DNA, and nuclear residence is not
the default fate of rough-ER products.
7. A scientist wants to separate a mixture of biomolecules primarily on the basis of molecular size.
Which general strategy is most appropriate?
Practice Examination | 2026/2027 Edition | Page 2
CHEM 210 final Module Exam | Biochemistry |
Portage Learning | Q & A | 2026/2027 actual
(PDF)
CHEM 210 FINAL EXAM
Biochemistry
Portage Learning
100-Question Practice Examination
2026/2027 Edition
1. A biochemist isolates a cellular structure surrounded by a phospholipid bilayer and containing
its own circular DNA. Which structure is most consistent with these observations?
A) Golgi apparatus
B) Lysosome
C) Mitochondrion
D) Peroxisome
Correct Answer: Mitochondrion
Rationale: Mitochondria are membrane-bound organelles that retain their own circular DNA, reflecting
their endosymbiotic origin. Lysosomes, the Golgi apparatus, and peroxisomes are membrane-bound but
do not contain an independent circular genome. Recognizing structural features helps connect cell
organization with biochemical function.
2. A molecule contains both a carbonyl group and a hydroxyl group on adjacent carbons. Which
conclusion is most reasonable?
A) It must be completely nonpolar
B) It cannot interact with water
C) It can participate in hydrogen bonding and polar reactions
D) It can form only ionic bonds
Correct Answer: It can participate in hydrogen bonding and polar reactions
Rationale: Carbonyl and hydroxyl groups are polar functional groups. The hydroxyl group can donate and
accept hydrogen bonds, while the carbonyl oxygen can accept them, so the molecule can interact
strongly with water and other polar species. The presence of these groups does not require ionic
bonding or complete nonpolarity.
3. Why is carbon especially well suited to form the molecular skeletons of biomolecules?
A) It is the most electronegative element
B) It exists only as an ion in cells
C) It can form four covalent bonds and stable chains or rings
Practice Examination | 2026/2027 Edition | Page 1
, CHEM 210 Final Exam - Biochemistry
D) It readily forms only one bond
Correct Answer: It can form four covalent bonds and stable chains or rings
Rationale: Carbon has four valence electrons and can form four stable covalent bonds, including bonds
to other carbon atoms. This supports chains, branches, rings, and multiple bonds that create biochemical
diversity. Carbon is not the most electronegative element and does not exist only in ionic form in cells.
4. Two molecules have the same molecular formula but different connectivity of their atoms. How
should they be classified?
A) Constitutional isomers
B) Identical molecules
C) Isotopes
D) Enantiomers only
Correct Answer: Constitutional isomers
Rationale: Constitutional isomers share a molecular formula but differ in how atoms are connected.
Isotopes differ in neutron number, while enantiomers specifically require non-superimposable mirror-
image stereochemistry rather than merely different connectivity. Distinguishing isomer types is important
because connectivity can strongly change biochemical reactivity.
5. A reaction in a cell links two small molecules while releasing water. Which reaction type best
describes this process?
A) Condensation reaction
B) Hydrolysis
C) Oxidative phosphorylation
D) Ionization
Correct Answer: Condensation reaction
Rationale: A condensation, or dehydration-synthesis, reaction forms a covalent bond while eliminating
water. Hydrolysis does the opposite by using water to break a bond. Oxidative phosphorylation concerns
ATP generation through an electron-transport-driven proton gradient, and ionization refers to gain or loss
of charged particles such as protons.
6. A protein is synthesized on ribosomes attached to rough endoplasmic reticulum. Which
destination is most plausible for the mature protein?
A) Exclusive use as cytosolic glycolytic enzyme
B) Conversion directly into DNA
C) Secretion from the cell or insertion into a membrane
D) Permanent storage inside the nucleus
Correct Answer: Secretion from the cell or insertion into a membrane
Rationale: Proteins translated on rough-ER-bound ribosomes commonly enter the secretory pathway,
becoming secreted proteins, lysosomal proteins, or membrane proteins. Most cytosolic enzymes are
translated on free ribosomes. Proteins are not directly converted into DNA, and nuclear residence is not
the default fate of rough-ER products.
7. A scientist wants to separate a mixture of biomolecules primarily on the basis of molecular size.
Which general strategy is most appropriate?
Practice Examination | 2026/2027 Edition | Page 2
