C785 Biochemistry - Week 2 Study Guide Comprehensive Quiz 2026
|WGU
1. Which type of bond is formed when electrons are shared equally between
two atoms?
A. Non-polar covalent bond
B. Polar covalent bond
C. Ionic bond
D. Hydrogen bond
Answer: A
Rationale: Non-polar covalent bonds occur when the electronegativity difference between
atoms is negligible, leading to equal electron sharing.
2. What is the primary reason water is considered a polar molecule?
A. It contains ionic bonds
B. Hydrogen atoms have a higher electronegativity than oxygen
C. It can dissolve lipids
D. Oxygen is more electronegative than hydrogen
Answer: D
Rationale: Oxygen’s higher electronegativity pulls electrons closer to itself, creating a
partial negative charge on oxygen and partial positive charges on hydrogen.
,3. Which property of water allows it to move upward through a plant’s xylem?
A. Cohesion and adhesion
B. High specific heat
C. High heat of vaporization
D. Density as a solid
Answer: A
Rationale: Cohesion (water-water attraction) and adhesion (water-surface attraction)
allow water to counteract gravity in narrow tubes.
4. A solution with a pH of 3 is how many times more acidic than a solution with
a pH of 5?
A. 2 times
B. 10 times
C. 100 times
D. 1000 times
Answer: C
Rationale: The pH scale is logarithmic; each unit represents a 10-fold difference in H+
concentration. Two units (5 minus 3) equals 10 squared, or 100.
5. Which functional group is characterized by a formula of -NH2?
A. Carboxyl
B. Hydroxyl
C. Phosphate
D. Amino
Answer: D
Rationale: The amino group consists of a nitrogen atom bonded to two hydrogen atoms.
, 6. Which macromolecule is primarily responsible for long-term energy storage in
animals?
A. Glucose
B. Triglycerides
C. Glycogen
D. Cellulose
Answer: B
Rationale: Triglycerides (fats) provide highly concentrated energy storage in adipose
tissue, whereas glycogen is for shorter-term use.
7. The secondary structure of a protein, such as an alpha-helix, is stabilized by
which type of interaction?
A. Disulfide bridges
B. Peptide bonds
C. Hydrophobic interactions between R-groups
D. Hydrogen bonds between backbone atoms
Answer: D
Rationale: Secondary structures are formed by hydrogen bonding between the carbonyl
oxygen and the amide hydrogen of the polypeptide backbone.
8. Which amino acid is known for creating kinks in the polypeptide chain due to
its cyclic R-group?
A. Proline
B. Glycine
C. Cysteine
D. Lysine
Answer: A
Rationale: Proline’s side chain is covalently bonded to the amino group nitrogen, forming a
ring that restricts rotation and disrupts secondary structures.
|WGU
1. Which type of bond is formed when electrons are shared equally between
two atoms?
A. Non-polar covalent bond
B. Polar covalent bond
C. Ionic bond
D. Hydrogen bond
Answer: A
Rationale: Non-polar covalent bonds occur when the electronegativity difference between
atoms is negligible, leading to equal electron sharing.
2. What is the primary reason water is considered a polar molecule?
A. It contains ionic bonds
B. Hydrogen atoms have a higher electronegativity than oxygen
C. It can dissolve lipids
D. Oxygen is more electronegative than hydrogen
Answer: D
Rationale: Oxygen’s higher electronegativity pulls electrons closer to itself, creating a
partial negative charge on oxygen and partial positive charges on hydrogen.
,3. Which property of water allows it to move upward through a plant’s xylem?
A. Cohesion and adhesion
B. High specific heat
C. High heat of vaporization
D. Density as a solid
Answer: A
Rationale: Cohesion (water-water attraction) and adhesion (water-surface attraction)
allow water to counteract gravity in narrow tubes.
4. A solution with a pH of 3 is how many times more acidic than a solution with
a pH of 5?
A. 2 times
B. 10 times
C. 100 times
D. 1000 times
Answer: C
Rationale: The pH scale is logarithmic; each unit represents a 10-fold difference in H+
concentration. Two units (5 minus 3) equals 10 squared, or 100.
5. Which functional group is characterized by a formula of -NH2?
A. Carboxyl
B. Hydroxyl
C. Phosphate
D. Amino
Answer: D
Rationale: The amino group consists of a nitrogen atom bonded to two hydrogen atoms.
, 6. Which macromolecule is primarily responsible for long-term energy storage in
animals?
A. Glucose
B. Triglycerides
C. Glycogen
D. Cellulose
Answer: B
Rationale: Triglycerides (fats) provide highly concentrated energy storage in adipose
tissue, whereas glycogen is for shorter-term use.
7. The secondary structure of a protein, such as an alpha-helix, is stabilized by
which type of interaction?
A. Disulfide bridges
B. Peptide bonds
C. Hydrophobic interactions between R-groups
D. Hydrogen bonds between backbone atoms
Answer: D
Rationale: Secondary structures are formed by hydrogen bonding between the carbonyl
oxygen and the amide hydrogen of the polypeptide backbone.
8. Which amino acid is known for creating kinks in the polypeptide chain due to
its cyclic R-group?
A. Proline
B. Glycine
C. Cysteine
D. Lysine
Answer: A
Rationale: Proline’s side chain is covalently bonded to the amino group nitrogen, forming a
ring that restricts rotation and disrupts secondary structures.
