Biology 101 — Exam 2
BIOLOGY 101 EXAM 2 | COMPLETE EXAM 2026/2027
ALL QUESTIONS AND CORRECT ANSWERS | PASS
GUARANTEE
Name: ________________________________ Date: ______________
Course/Section: ________________________________
1. Which subatomic particle carries a negative charge?
A. Proton
B. Neutron
C. Electron
D. Positron
C. Electron — Electrons are negatively charged particles that occupy the
space surrounding the nucleus.
2. The atomic number of an element is determined by its number of:
A. Neutrons
B. Protons
C. Electrons
D. Isotopes
B. Protons — Atomic number is defined by the number of protons in the
nucleus.
3. Isotopes of the same element differ in their number of:
A. Protons
B. Electrons
C. Neutrons
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, Biology 101 — Exam 2
D. Valence electrons
C. Neutrons — Isotopes have the same proton number but different
neutron numbers, changing atomic mass.
4. A covalent bond forms when atoms:
A. Transfer electrons completely
B. Share pairs of electrons
C. Attract as oppositely charged ions
D. Form hydrogen bonds only
B. Share pairs of electrons — Covalent bonds involve two atoms sharing
one or more electron pairs.
5. Water is a polar molecule because:
A. It carries no charge at all
B. Oxygen pulls shared electrons more strongly than hydrogen
C. It is held together by ionic bonds
D. It cannot form hydrogen bonds
B. Oxygen pulls shared electrons more strongly than hydrogen —
Oxygen's greater electronegativity gives water molecules partial negative
and positive ends.
6. Hydrogen bonding between water molecules is chiefly responsible
for water's:
A. High surface tension
B. Very low specific heat
C. Low boiling point relative to its size
D. Nonpolar behavior
A. High surface tension — Hydrogen bonds pull surface water molecules
together, producing high surface tension.
7. The pH scale is a measure of a solution's:
A. Sugar concentration
B. Hydrogen ion (H+) concentration
C. Oxygen concentration
D. Salt concentration
B. Hydrogen ion (H+) concentration — pH reflects the concentration of
hydrogen ions; lower pH means more H+.
8. A solution with a pH of 3 would be classified as:
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, Biology 101 — Exam 2
A. Strongly basic
B. Neutral
C. Acidic
D. Amphoteric
C. Acidic — Values below 7 on the pH scale indicate an acidic solution.
9. Water striders can walk on water mainly because of:
A. Adhesion to the air
B. Cohesion creating surface tension
C. Water's high density as ice
D. Capillary action in their legs
B. Cohesion creating surface tension — Hydrogen-bond-driven cohesion
produces a surface tension strong enough to support small insects.
10. Ice floats on liquid water because:
A. Ice is denser than liquid water
B. Hydrogen bonds lock water into a less dense crystal lattice when
frozen
C. Ice contains trapped air bubbles only
D. Water molecules stop existing when frozen
B. Hydrogen bonds lock water into a less dense crystal lattice when
frozen — Freezing arranges water molecules into an open lattice that is
less dense than the liquid form.
11. A buffer helps a biological system by:
A. Rapidly raising pH
B. Resisting changes in pH when acids or bases are added
C. Permanently neutralizing all acids
D. Removing every ion from a solution
B. Resisting changes in pH when acids or bases are added — Buffers
absorb small additions of acid or base, keeping pH relatively stable.
12. The four elements that make up the vast majority of living matter
are:
A. C, H, O, N
B. Na, K, Cl, Ca
C. Fe, Mg, S, P
D. C, Si, O, H
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, Biology 101 — Exam 2
A. C, H, O, N — Carbon, hydrogen, oxygen, and nitrogen form the bulk of
biological molecules.
13. An ionic bond forms when:
A. Electrons are shared equally between atoms
B. One atom transfers an electron to another, creating charged ions
C. Two atoms share neutrons
D. Atoms simply repel one another
B. One atom transfers an electron to another, creating charged ions —
Ionic bonds arise from electrostatic attraction after electron transfer
creates a cation and anion.
14. Cohesion in water refers to:
A. Attraction between water and other polar substances
B. Attraction between water molecules themselves
C. Repulsion of nonpolar molecules by water
D. The bond between hydrogen and oxygen within one molecule
B. Attraction between water molecules themselves — Cohesion is the
mutual attraction of water molecules to each other via hydrogen bonds.
15. Water's high specific heat benefits living organisms by:
A. Causing rapid temperature swings
B. Helping moderate temperature fluctuations in cells and environments
C. Increasing evaporation rate dramatically
D. Preventing any hydrogen bonding
B. Helping moderate temperature fluctuations in cells and environments
— Water absorbs or releases a lot of heat with only small temperature
change, buffering organisms from swings.
Section — Macromolecules (Questions 16–40)
16. Carbohydrates are built from monomers called:
A. Amino acids
B. Monosaccharides
C. Nucleotides
D. Fatty acids
B. Monosaccharides — Simple sugars, or monosaccharides, are the
building blocks of carbohydrates.
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BIOLOGY 101 EXAM 2 | COMPLETE EXAM 2026/2027
ALL QUESTIONS AND CORRECT ANSWERS | PASS
GUARANTEE
Name: ________________________________ Date: ______________
Course/Section: ________________________________
1. Which subatomic particle carries a negative charge?
A. Proton
B. Neutron
C. Electron
D. Positron
C. Electron — Electrons are negatively charged particles that occupy the
space surrounding the nucleus.
2. The atomic number of an element is determined by its number of:
A. Neutrons
B. Protons
C. Electrons
D. Isotopes
B. Protons — Atomic number is defined by the number of protons in the
nucleus.
3. Isotopes of the same element differ in their number of:
A. Protons
B. Electrons
C. Neutrons
Page 1 of 46
, Biology 101 — Exam 2
D. Valence electrons
C. Neutrons — Isotopes have the same proton number but different
neutron numbers, changing atomic mass.
4. A covalent bond forms when atoms:
A. Transfer electrons completely
B. Share pairs of electrons
C. Attract as oppositely charged ions
D. Form hydrogen bonds only
B. Share pairs of electrons — Covalent bonds involve two atoms sharing
one or more electron pairs.
5. Water is a polar molecule because:
A. It carries no charge at all
B. Oxygen pulls shared electrons more strongly than hydrogen
C. It is held together by ionic bonds
D. It cannot form hydrogen bonds
B. Oxygen pulls shared electrons more strongly than hydrogen —
Oxygen's greater electronegativity gives water molecules partial negative
and positive ends.
6. Hydrogen bonding between water molecules is chiefly responsible
for water's:
A. High surface tension
B. Very low specific heat
C. Low boiling point relative to its size
D. Nonpolar behavior
A. High surface tension — Hydrogen bonds pull surface water molecules
together, producing high surface tension.
7. The pH scale is a measure of a solution's:
A. Sugar concentration
B. Hydrogen ion (H+) concentration
C. Oxygen concentration
D. Salt concentration
B. Hydrogen ion (H+) concentration — pH reflects the concentration of
hydrogen ions; lower pH means more H+.
8. A solution with a pH of 3 would be classified as:
Page 2 of 46
, Biology 101 — Exam 2
A. Strongly basic
B. Neutral
C. Acidic
D. Amphoteric
C. Acidic — Values below 7 on the pH scale indicate an acidic solution.
9. Water striders can walk on water mainly because of:
A. Adhesion to the air
B. Cohesion creating surface tension
C. Water's high density as ice
D. Capillary action in their legs
B. Cohesion creating surface tension — Hydrogen-bond-driven cohesion
produces a surface tension strong enough to support small insects.
10. Ice floats on liquid water because:
A. Ice is denser than liquid water
B. Hydrogen bonds lock water into a less dense crystal lattice when
frozen
C. Ice contains trapped air bubbles only
D. Water molecules stop existing when frozen
B. Hydrogen bonds lock water into a less dense crystal lattice when
frozen — Freezing arranges water molecules into an open lattice that is
less dense than the liquid form.
11. A buffer helps a biological system by:
A. Rapidly raising pH
B. Resisting changes in pH when acids or bases are added
C. Permanently neutralizing all acids
D. Removing every ion from a solution
B. Resisting changes in pH when acids or bases are added — Buffers
absorb small additions of acid or base, keeping pH relatively stable.
12. The four elements that make up the vast majority of living matter
are:
A. C, H, O, N
B. Na, K, Cl, Ca
C. Fe, Mg, S, P
D. C, Si, O, H
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, Biology 101 — Exam 2
A. C, H, O, N — Carbon, hydrogen, oxygen, and nitrogen form the bulk of
biological molecules.
13. An ionic bond forms when:
A. Electrons are shared equally between atoms
B. One atom transfers an electron to another, creating charged ions
C. Two atoms share neutrons
D. Atoms simply repel one another
B. One atom transfers an electron to another, creating charged ions —
Ionic bonds arise from electrostatic attraction after electron transfer
creates a cation and anion.
14. Cohesion in water refers to:
A. Attraction between water and other polar substances
B. Attraction between water molecules themselves
C. Repulsion of nonpolar molecules by water
D. The bond between hydrogen and oxygen within one molecule
B. Attraction between water molecules themselves — Cohesion is the
mutual attraction of water molecules to each other via hydrogen bonds.
15. Water's high specific heat benefits living organisms by:
A. Causing rapid temperature swings
B. Helping moderate temperature fluctuations in cells and environments
C. Increasing evaporation rate dramatically
D. Preventing any hydrogen bonding
B. Helping moderate temperature fluctuations in cells and environments
— Water absorbs or releases a lot of heat with only small temperature
change, buffering organisms from swings.
Section — Macromolecules (Questions 16–40)
16. Carbohydrates are built from monomers called:
A. Amino acids
B. Monosaccharides
C. Nucleotides
D. Fatty acids
B. Monosaccharides — Simple sugars, or monosaccharides, are the
building blocks of carbohydrates.
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