BIOL 101 Quiz 2 V1 | BIOL 101 Principles of
Biology | Actual Q&A with Rationale (BIOL101 Quiz
2) | Liberty University
1. Which of the following components is the primary constituent of the plasma membrane,
providing it with its unique fluid-like properties?
A. Integral proteins
B. Cholesterol molecules
C. Phospholipids organized in a bilayer
D. Glycoproteins
Correct Answer: C
Explanation: The plasma membrane is fundamentally composed of a phospholipid bilayer
where the hydrophobic tails point inward. This structure allows the membrane to remain
flexible and selectively permeable to various solutes. It is described by the fluid mosaic
model, which highlights the movement of these lipids and associated proteins.
2. According to the Second Law of Thermodynamics, which of the following statements is true
regarding every energy transfer or transformation?
A. The total amount of energy in the universe increases.
B. The entropy of the universe increases.
C. Energy is destroyed during the transformation process.
,D. Order within a closed system is spontaneously maintained.
Correct Answer: B
Explanation: The Second Law of Thermodynamics dictates that energy transfers are never
100% efficient, resulting in the loss of usable energy as heat. This loss contributes to an
overall increase in the disorder or randomness of the universe. Consequently, systems
require constant energy input to maintain high levels of organization.
3. In cellular respiration, what is the specific role of NAD+?
A. It serves as an electron carrier that accepts electrons to become NADH.
B. It functions as an enzyme to catalyze the conversion of glucose.
C. It acts as a final electron acceptor in the electron transport chain.
D. It provides the phosphate group needed for ATP synthesis.
Correct Answer: A
Explanation: NAD+ is a coenzyme that functions as an oxidizing agent by accepting
electrons during various stages of cellular respiration. When it accepts two electrons and a
proton, it is reduced to NADH. This NADH then transports the high-energy electrons to the
electron transport chain to facilitate ATP production.
4. Where does the Citric Acid Cycle (Krebs Cycle) occur within a eukaryotic cell?
A. Cytosol
B. Intermembrane space of the mitochondria
, C. Mitochondrial matrix
D. Inner mitochondrial membrane (cristae)
Correct Answer: C
Explanation: The Citric Acid Cycle takes place in the mitochondrial matrix, which is the
innermost compartment of the organelle. This follows the oxidation of pyruvate which
enters the matrix from the cytosol. The enzymes required for this cyclic metabolic pathway
are localized specifically in this fluid-filled space.
5. What is the primary function of the light-dependent reactions in photosynthesis?
A. To fix carbon dioxide into organic molecules.
B. To release carbon dioxide into the atmosphere.
C. To produce glucose directly from sunlight.
D. To convert solar energy into chemical energy in the form of ATP and NADPH.
Correct Answer: D
Explanation: The light-dependent reactions occur in the thylakoid membranes of the
chloroplasts where chlorophyll absorbs solar energy. This energy is used to drive the
transfer of electrons and protons, ultimately generating ATP and NADPH. These two
molecules are essential power sources for the subsequent Calvin Cycle.
Biology | Actual Q&A with Rationale (BIOL101 Quiz
2) | Liberty University
1. Which of the following components is the primary constituent of the plasma membrane,
providing it with its unique fluid-like properties?
A. Integral proteins
B. Cholesterol molecules
C. Phospholipids organized in a bilayer
D. Glycoproteins
Correct Answer: C
Explanation: The plasma membrane is fundamentally composed of a phospholipid bilayer
where the hydrophobic tails point inward. This structure allows the membrane to remain
flexible and selectively permeable to various solutes. It is described by the fluid mosaic
model, which highlights the movement of these lipids and associated proteins.
2. According to the Second Law of Thermodynamics, which of the following statements is true
regarding every energy transfer or transformation?
A. The total amount of energy in the universe increases.
B. The entropy of the universe increases.
C. Energy is destroyed during the transformation process.
,D. Order within a closed system is spontaneously maintained.
Correct Answer: B
Explanation: The Second Law of Thermodynamics dictates that energy transfers are never
100% efficient, resulting in the loss of usable energy as heat. This loss contributes to an
overall increase in the disorder or randomness of the universe. Consequently, systems
require constant energy input to maintain high levels of organization.
3. In cellular respiration, what is the specific role of NAD+?
A. It serves as an electron carrier that accepts electrons to become NADH.
B. It functions as an enzyme to catalyze the conversion of glucose.
C. It acts as a final electron acceptor in the electron transport chain.
D. It provides the phosphate group needed for ATP synthesis.
Correct Answer: A
Explanation: NAD+ is a coenzyme that functions as an oxidizing agent by accepting
electrons during various stages of cellular respiration. When it accepts two electrons and a
proton, it is reduced to NADH. This NADH then transports the high-energy electrons to the
electron transport chain to facilitate ATP production.
4. Where does the Citric Acid Cycle (Krebs Cycle) occur within a eukaryotic cell?
A. Cytosol
B. Intermembrane space of the mitochondria
, C. Mitochondrial matrix
D. Inner mitochondrial membrane (cristae)
Correct Answer: C
Explanation: The Citric Acid Cycle takes place in the mitochondrial matrix, which is the
innermost compartment of the organelle. This follows the oxidation of pyruvate which
enters the matrix from the cytosol. The enzymes required for this cyclic metabolic pathway
are localized specifically in this fluid-filled space.
5. What is the primary function of the light-dependent reactions in photosynthesis?
A. To fix carbon dioxide into organic molecules.
B. To release carbon dioxide into the atmosphere.
C. To produce glucose directly from sunlight.
D. To convert solar energy into chemical energy in the form of ATP and NADPH.
Correct Answer: D
Explanation: The light-dependent reactions occur in the thylakoid membranes of the
chloroplasts where chlorophyll absorbs solar energy. This energy is used to drive the
transfer of electrons and protons, ultimately generating ATP and NADPH. These two
molecules are essential power sources for the subsequent Calvin Cycle.
