BIOCHEM 210 FINAL EXAM —
Portage Learning-aligned ORIGINAL practice examination • 250 questions • answers marked
Important: This is an original study/practice exam modeled on the subject areas in the Portage Learning CHEM 210 syllabus. It is not a copy of a live, restricted,
or leaked Portage Learning final exam, and no score or pass guarantee is implied.
MODULE 1 — FOUNDATIONS OF BIOCHEMISTRY
1. A molecule has a molecular mass of 1,000 g/mol. Which statement is most accurate?
• It is automatically a macromolecule
■ It is below the usual mass range used for macromolecules
• It must be a protein
• It must be a nucleic acid
Answer rationale: Macromolecules are generally much larger; course materials commonly use about 5,000 g/mol as a rough lower
boundary.
2. Which property makes carbon especially versatile in biomolecules?
■ It commonly forms four covalent bonds
• It forms only ionic bonds
• It cannot form multiple bonds
• It isAnswer
chemically inert
rationale: Carbon's tetravalence permits chains, rings, and multiple-bonded structures.
3. Which functional group is characteristic of an alcohol?
• –COOH
• –NH■
■ –OH
• –PO■²■
Answer rationale: An alcohol contains a hydroxyl group attached to carbon.
4. Which functional group is characteristic of an amine?
■ –NH■
• –COOH
BioChem 210 Final Exam Practice • 2026/2027 • Original study material Page 1
, • –CHO
• –SH
Answer rationale: Amino groups contain nitrogen and commonly occur as –NH■ or protonated variants.
5. Carbon dioxide has which geometry around its carbon atom?
• Bent, about 104.5°
• Trigonal planar, about 120°
■ Linear, 180°
• Tetrahedral, 109.5°
Answer rationale: CO■ has two electron domains around carbon and is linear.
6. A hydrogen bond is best described as:
• A covalent bond between two hydrogens
■ An attraction involving a partially positive H and an electronegative atom
• A bond stronger than a covalent bond
• AnAnswer
ionic bond inside a salt
rationale: Hydrogen bonds are noncovalent attractions involving H attached to an electronegative atom and an electronegative
acceptor.
7. Why does water act as an excellent solvent for many ionic compounds?
• It is nonpolar
■ Its polarity stabilizes separated charges
• It contains no hydrogen bonds
• It cannot interact with ions
Answer rationale: Water's partial charges allow it to surround and stabilize ions.
8. Which change would generally increase the hydrogen-ion concentration of a solution?
• Increasing pH
■ Adding a strong acid
• Adding hydroxide
• Diluting with pure water
Answer rationale: A strong acid increases [H■].
9. A solution has [H■] = 1 × 10■³ M. What is its pH?
■3
•7
• 10
• 13Answer rationale: pH = −log[H■] = 3.
10. A solution at pH 9 is how many times less acidic than a solution at pH 7?
• 2 times
• 10 times
■ 100 times
• 1,000 times
Answer rationale: Each pH unit represents a tenfold change in [H■]; two units = 100-fold.
11. A buffer works best when it contains:
• Only a strong acid
• Only a strong base
■ A weak acid/base pair capable of absorbing added acid or base
• NoAnswer
dissolved ions
rationale: Buffers resist pH changes by reversible proton transfer within a conjugate pair.
12. If a buffer has equal concentrations of a weak acid and its conjugate base, the Henderson-Hasselbalch
relationship predicts:
■ pH = pKa
• pH = 0
BioChem 210 Final Exam Practice • 2026/2027 • Original study material Page 2
, • pH = 14
• pHAnswer
= 2pKa
rationale: When [A■] = [HA], log([A■]/[HA]) = 0, so pH = pKa.
13. Which statement about covalent bonds is correct?
■ They involve sharing electrons
• They always involve complete electron transfer
• They are always weaker than hydrogen bonds
• They occur only between ions
Answer rationale: Covalent bonds involve shared electron pairs.
14. Which particle has a negative charge?
• Proton
• Neutron
■ Electron
• Nucleus
Answer rationale: Electrons carry negative charge.
15. An atom's atomic number equals its number of:
• Neutrons only
■ Protons
• Protons plus neutrons
• Electrons plus neutrons
Answer rationale: Atomic number is defined by proton count.
16. Isotopes of an element differ in their number of:
• Protons
■ Neutrons
• Atomic numbers
• Element identities
Answer rationale: Isotopes have the same proton number but different neutron numbers.
17. Which organelle contains most of the cell's DNA in a typical human cell?
• Lysosome
• Golgi apparatus
■ Nucleus
• Peroxisome
Answer rationale: The nucleus contains the nuclear genome.
18. Which organelle is primarily responsible for ATP production by oxidative phosphorylation?
■ Mitochondrion
• Lysosome
• Golgi apparatus
• Ribosome
Answer rationale: The inner mitochondrial membrane houses the electron transport chain and ATP synthase.
19. Which organelle is most directly associated with protein synthesis?
■ Ribosome
• Lysosome
• Peroxisome
• Centrosome
Answer rationale: Ribosomes translate mRNA into polypeptides.
20. Which organelle is specialized for degradation of many macromolecules?
■ Lysosome
• Nucleus
• Smooth ER
• Centrosome
BioChem 210 Final Exam Practice • 2026/2027 • Original study material Page 3
, Answer rationale: Lysosomes contain acid hydrolases for degradation.
21. Peroxisomes are especially important for:
• DNA replication
■ Certain oxidative reactions and fatty-acid processing
• Translation
• Ribosomal RNA synthesis
Answer rationale: Peroxisomes carry out oxidative reactions and specific lipid metabolic functions.
22. The plasma membrane is best described as:
• A rigid carbohydrate shell
■ A phospholipid bilayer containing proteins
• A layer made only of cholesterol
• A protein-free lipid monolayer
Answer rationale: Cell membranes are phospholipid bilayers with embedded proteins and other components.
23. Which molecule is amphipathic?
■ A phospholipid
• Sodium chloride only
• A simple hydrocarbon with no polar group
• Molecular oxygen
Answer rationale: Phospholipids have hydrophilic and hydrophobic regions.
24. What is the main immediate effect of increasing membrane cholesterol in many animal-cell membranes?
■ It can modulate membrane fluidity and permeability
• It converts the bilayer into a protein sheet
• It eliminates all membrane proteins
• It makes the membrane completely rigid at all temperatures
Answer rationale: Cholesterol buffers membrane fluidity and reduces permeability to some small polar molecules.
25. Diffusion down a concentration gradient requires:
• ATP hydrolysis
■ A concentration gradient
• A ribosome
• DNA polymerase
Answer rationale: Passive diffusion is driven by a concentration or electrochemical gradient.
26. Osmosis refers specifically to movement of:
• Proteins across ribosomes
■ Water across a selectively permeable membrane
• DNA into mitochondria
• ATP into lysosomes
Answer rationale: Osmosis is water movement driven by differences in effective solute concentration.
27. A cell placed in a strongly hypotonic solution is most likely to:
• Lose water and shrink
■ Gain water and swell
• Remain unchanged in all cases
• Lose all intracellular proteins immediately
Answer rationale: Water moves into the cell when the extracellular solution is hypotonic.
28. Which interaction is strongest among the following under typical biological conditions?
• Hydrogen bond
• Van der Waals interaction
■ Covalent bond
• Hydrophobic effect
Answer rationale: Covalent bonds are substantially stronger than these noncovalent interactions.
29. The hydrophobic effect is most directly related to:
BioChem 210 Final Exam Practice • 2026/2027 • Original study material Page 4
Portage Learning-aligned ORIGINAL practice examination • 250 questions • answers marked
Important: This is an original study/practice exam modeled on the subject areas in the Portage Learning CHEM 210 syllabus. It is not a copy of a live, restricted,
or leaked Portage Learning final exam, and no score or pass guarantee is implied.
MODULE 1 — FOUNDATIONS OF BIOCHEMISTRY
1. A molecule has a molecular mass of 1,000 g/mol. Which statement is most accurate?
• It is automatically a macromolecule
■ It is below the usual mass range used for macromolecules
• It must be a protein
• It must be a nucleic acid
Answer rationale: Macromolecules are generally much larger; course materials commonly use about 5,000 g/mol as a rough lower
boundary.
2. Which property makes carbon especially versatile in biomolecules?
■ It commonly forms four covalent bonds
• It forms only ionic bonds
• It cannot form multiple bonds
• It isAnswer
chemically inert
rationale: Carbon's tetravalence permits chains, rings, and multiple-bonded structures.
3. Which functional group is characteristic of an alcohol?
• –COOH
• –NH■
■ –OH
• –PO■²■
Answer rationale: An alcohol contains a hydroxyl group attached to carbon.
4. Which functional group is characteristic of an amine?
■ –NH■
• –COOH
BioChem 210 Final Exam Practice • 2026/2027 • Original study material Page 1
, • –CHO
• –SH
Answer rationale: Amino groups contain nitrogen and commonly occur as –NH■ or protonated variants.
5. Carbon dioxide has which geometry around its carbon atom?
• Bent, about 104.5°
• Trigonal planar, about 120°
■ Linear, 180°
• Tetrahedral, 109.5°
Answer rationale: CO■ has two electron domains around carbon and is linear.
6. A hydrogen bond is best described as:
• A covalent bond between two hydrogens
■ An attraction involving a partially positive H and an electronegative atom
• A bond stronger than a covalent bond
• AnAnswer
ionic bond inside a salt
rationale: Hydrogen bonds are noncovalent attractions involving H attached to an electronegative atom and an electronegative
acceptor.
7. Why does water act as an excellent solvent for many ionic compounds?
• It is nonpolar
■ Its polarity stabilizes separated charges
• It contains no hydrogen bonds
• It cannot interact with ions
Answer rationale: Water's partial charges allow it to surround and stabilize ions.
8. Which change would generally increase the hydrogen-ion concentration of a solution?
• Increasing pH
■ Adding a strong acid
• Adding hydroxide
• Diluting with pure water
Answer rationale: A strong acid increases [H■].
9. A solution has [H■] = 1 × 10■³ M. What is its pH?
■3
•7
• 10
• 13Answer rationale: pH = −log[H■] = 3.
10. A solution at pH 9 is how many times less acidic than a solution at pH 7?
• 2 times
• 10 times
■ 100 times
• 1,000 times
Answer rationale: Each pH unit represents a tenfold change in [H■]; two units = 100-fold.
11. A buffer works best when it contains:
• Only a strong acid
• Only a strong base
■ A weak acid/base pair capable of absorbing added acid or base
• NoAnswer
dissolved ions
rationale: Buffers resist pH changes by reversible proton transfer within a conjugate pair.
12. If a buffer has equal concentrations of a weak acid and its conjugate base, the Henderson-Hasselbalch
relationship predicts:
■ pH = pKa
• pH = 0
BioChem 210 Final Exam Practice • 2026/2027 • Original study material Page 2
, • pH = 14
• pHAnswer
= 2pKa
rationale: When [A■] = [HA], log([A■]/[HA]) = 0, so pH = pKa.
13. Which statement about covalent bonds is correct?
■ They involve sharing electrons
• They always involve complete electron transfer
• They are always weaker than hydrogen bonds
• They occur only between ions
Answer rationale: Covalent bonds involve shared electron pairs.
14. Which particle has a negative charge?
• Proton
• Neutron
■ Electron
• Nucleus
Answer rationale: Electrons carry negative charge.
15. An atom's atomic number equals its number of:
• Neutrons only
■ Protons
• Protons plus neutrons
• Electrons plus neutrons
Answer rationale: Atomic number is defined by proton count.
16. Isotopes of an element differ in their number of:
• Protons
■ Neutrons
• Atomic numbers
• Element identities
Answer rationale: Isotopes have the same proton number but different neutron numbers.
17. Which organelle contains most of the cell's DNA in a typical human cell?
• Lysosome
• Golgi apparatus
■ Nucleus
• Peroxisome
Answer rationale: The nucleus contains the nuclear genome.
18. Which organelle is primarily responsible for ATP production by oxidative phosphorylation?
■ Mitochondrion
• Lysosome
• Golgi apparatus
• Ribosome
Answer rationale: The inner mitochondrial membrane houses the electron transport chain and ATP synthase.
19. Which organelle is most directly associated with protein synthesis?
■ Ribosome
• Lysosome
• Peroxisome
• Centrosome
Answer rationale: Ribosomes translate mRNA into polypeptides.
20. Which organelle is specialized for degradation of many macromolecules?
■ Lysosome
• Nucleus
• Smooth ER
• Centrosome
BioChem 210 Final Exam Practice • 2026/2027 • Original study material Page 3
, Answer rationale: Lysosomes contain acid hydrolases for degradation.
21. Peroxisomes are especially important for:
• DNA replication
■ Certain oxidative reactions and fatty-acid processing
• Translation
• Ribosomal RNA synthesis
Answer rationale: Peroxisomes carry out oxidative reactions and specific lipid metabolic functions.
22. The plasma membrane is best described as:
• A rigid carbohydrate shell
■ A phospholipid bilayer containing proteins
• A layer made only of cholesterol
• A protein-free lipid monolayer
Answer rationale: Cell membranes are phospholipid bilayers with embedded proteins and other components.
23. Which molecule is amphipathic?
■ A phospholipid
• Sodium chloride only
• A simple hydrocarbon with no polar group
• Molecular oxygen
Answer rationale: Phospholipids have hydrophilic and hydrophobic regions.
24. What is the main immediate effect of increasing membrane cholesterol in many animal-cell membranes?
■ It can modulate membrane fluidity and permeability
• It converts the bilayer into a protein sheet
• It eliminates all membrane proteins
• It makes the membrane completely rigid at all temperatures
Answer rationale: Cholesterol buffers membrane fluidity and reduces permeability to some small polar molecules.
25. Diffusion down a concentration gradient requires:
• ATP hydrolysis
■ A concentration gradient
• A ribosome
• DNA polymerase
Answer rationale: Passive diffusion is driven by a concentration or electrochemical gradient.
26. Osmosis refers specifically to movement of:
• Proteins across ribosomes
■ Water across a selectively permeable membrane
• DNA into mitochondria
• ATP into lysosomes
Answer rationale: Osmosis is water movement driven by differences in effective solute concentration.
27. A cell placed in a strongly hypotonic solution is most likely to:
• Lose water and shrink
■ Gain water and swell
• Remain unchanged in all cases
• Lose all intracellular proteins immediately
Answer rationale: Water moves into the cell when the extracellular solution is hypotonic.
28. Which interaction is strongest among the following under typical biological conditions?
• Hydrogen bond
• Van der Waals interaction
■ Covalent bond
• Hydrophobic effect
Answer rationale: Covalent bonds are substantially stronger than these noncovalent interactions.
29. The hydrophobic effect is most directly related to:
BioChem 210 Final Exam Practice • 2026/2027 • Original study material Page 4
