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CHEM 210 Biochemistry Module 1
Exam (2024/2025) – Portage Learning
Questions and Verified Answers |
100% Guarantee Pass
Multiple Choice Questions
1. What is the primary source of an atom’s chemical reactivity?
A. Protons in the nucleus
B. Valence electrons
C. Neutrons in the nucleus
D. Inner shell electrons
Correct Answer: B. Valence electrons
Rationale: Valence electrons, located in the outermost shell, determine an atom’s ability
to form chemical bonds by interacting with other atoms. Protons and neutrons influence
nuclear properties, and inner shell electrons are not typically involved in bonding.
2. Which subatomic particle determines an element’s identity?
A. Electron
B. Proton
C. Neutron
D. Photon
Correct Answer: B. Proton
Rationale: The number of protons (atomic number) defines an element’s identity on the
periodic table. Electrons affect charge, neutrons affect mass, and photons are not
subatomic particles.
3. What type of bond involves the complete transfer of electrons between atoms?
A. Covalent bond
B. Ionic bond
C. Hydrogen bond
D. Metallic bond
Correct Answer: B. Ionic bond
Rationale: Ionic bonds form when electrons are transferred from one atom to another,
creating oppositely charged ions that attract. Covalent bonds involve electron sharing,
hydrogen bonds are weaker interactions, and metallic bonds occur in metals.
4. Which element is most likely to form a covalent bond?
A. Sodium (Na)
B. Carbon (C)
C. Potassium (K)
D. Calcium (Ca)
, 2
Correct Answer: B. Carbon (C)
Rationale: Carbon, a nonmetal, forms covalent bonds by sharing electrons due to its four
valence electrons. Sodium, potassium, and calcium are metals that typically form ionic
bonds.
5. What is the bond angle in a water molecule?
A. 90°
B. 104.5°
C. 120°
D. 180°
Correct Answer: B. 104.5°
Rationale: Water’s bent molecular geometry, due to two lone pairs on oxygen, results in
a bond angle of approximately 104.5°. The other angles correspond to different molecular
geometries.
6. Which property of water allows it to dissolve polar substances?
A. High boiling point
B. Polarity
C. Low density as ice
D. High specific heat
Correct Answer: B. Polarity
Rationale: Water’s polarity, with partial positive (hydrogen) and negative (oxygen)
charges, enables it to interact with and dissolve other polar substances via dipole-dipole
interactions.
7. What type of bond stabilizes the secondary structure of proteins?
A. Ionic bond
B. Covalent bond
C. Hydrogen bond
D. Disulfide bond
Correct Answer: C. Hydrogen bond
Rationale: Hydrogen bonds between the backbone carbonyl oxygen and amide hydrogen
stabilize secondary protein structures like alpha helices and beta sheets. Disulfide bonds
are covalent and stabilize tertiary structures.
8. Which macromolecule is primarily responsible for energy storage in cells?
A. Proteins
B. Carbohydrates
C. Nucleic acids
D. Lipids
Correct Answer: B. Carbohydrates
Rationale: Carbohydrates, such as glycogen and starch, are the primary energy storage
molecules in cells. Lipids store energy long-term, proteins have structural roles, and
nucleic acids store genetic information.
9. What is the atomic number of an element with 8 protons and 10 neutrons?
A. 8
B. 10
C. 18
D. 2
Correct Answer: A. 8
CHEM 210 Biochemistry Module 1
Exam (2024/2025) – Portage Learning
Questions and Verified Answers |
100% Guarantee Pass
Multiple Choice Questions
1. What is the primary source of an atom’s chemical reactivity?
A. Protons in the nucleus
B. Valence electrons
C. Neutrons in the nucleus
D. Inner shell electrons
Correct Answer: B. Valence electrons
Rationale: Valence electrons, located in the outermost shell, determine an atom’s ability
to form chemical bonds by interacting with other atoms. Protons and neutrons influence
nuclear properties, and inner shell electrons are not typically involved in bonding.
2. Which subatomic particle determines an element’s identity?
A. Electron
B. Proton
C. Neutron
D. Photon
Correct Answer: B. Proton
Rationale: The number of protons (atomic number) defines an element’s identity on the
periodic table. Electrons affect charge, neutrons affect mass, and photons are not
subatomic particles.
3. What type of bond involves the complete transfer of electrons between atoms?
A. Covalent bond
B. Ionic bond
C. Hydrogen bond
D. Metallic bond
Correct Answer: B. Ionic bond
Rationale: Ionic bonds form when electrons are transferred from one atom to another,
creating oppositely charged ions that attract. Covalent bonds involve electron sharing,
hydrogen bonds are weaker interactions, and metallic bonds occur in metals.
4. Which element is most likely to form a covalent bond?
A. Sodium (Na)
B. Carbon (C)
C. Potassium (K)
D. Calcium (Ca)
, 2
Correct Answer: B. Carbon (C)
Rationale: Carbon, a nonmetal, forms covalent bonds by sharing electrons due to its four
valence electrons. Sodium, potassium, and calcium are metals that typically form ionic
bonds.
5. What is the bond angle in a water molecule?
A. 90°
B. 104.5°
C. 120°
D. 180°
Correct Answer: B. 104.5°
Rationale: Water’s bent molecular geometry, due to two lone pairs on oxygen, results in
a bond angle of approximately 104.5°. The other angles correspond to different molecular
geometries.
6. Which property of water allows it to dissolve polar substances?
A. High boiling point
B. Polarity
C. Low density as ice
D. High specific heat
Correct Answer: B. Polarity
Rationale: Water’s polarity, with partial positive (hydrogen) and negative (oxygen)
charges, enables it to interact with and dissolve other polar substances via dipole-dipole
interactions.
7. What type of bond stabilizes the secondary structure of proteins?
A. Ionic bond
B. Covalent bond
C. Hydrogen bond
D. Disulfide bond
Correct Answer: C. Hydrogen bond
Rationale: Hydrogen bonds between the backbone carbonyl oxygen and amide hydrogen
stabilize secondary protein structures like alpha helices and beta sheets. Disulfide bonds
are covalent and stabilize tertiary structures.
8. Which macromolecule is primarily responsible for energy storage in cells?
A. Proteins
B. Carbohydrates
C. Nucleic acids
D. Lipids
Correct Answer: B. Carbohydrates
Rationale: Carbohydrates, such as glycogen and starch, are the primary energy storage
molecules in cells. Lipids store energy long-term, proteins have structural roles, and
nucleic acids store genetic information.
9. What is the atomic number of an element with 8 protons and 10 neutrons?
A. 8
B. 10
C. 18
D. 2
Correct Answer: A. 8
