BIOL 101 Final Exam V3 | BIOL 101 Principles of Biology | Actual Q&A
with Rationale (BIOL101 Final Exam) | Liberty University
1. Which of the following best describes the structural component of a cell membrane that
allows it to be fluid yet stable?
A. A phospholipid bilayer with embedded proteins and cholesterol
B. A rigid layer of cellulose
C. A solid wall of chitin and mineral salts
D. A single layer of glycoproteins
Correct Answer: A
Explanation: The cell membrane is composed of a phospholipid bilayer which provides a
flexible matrix. Proteins are embedded within this layer to facilitate transport and
signaling, while cholesterol molecules help regulate fluidity at different temperatures. This
‘fluid mosaic model’ is essential for maintaining the cell’s integrity while allowing for the
movement of essential materials.
2. In the process of photosynthesis, what is the primary purpose of the Light-Dependent
Reactions?
A. To convert light energy into chemical energy in the form of ATP and NADPH
B. To produce water as a byproduct for the plant
C. To fix carbon dioxide into glucose molecules
D. To breakdown glucose into pyruvate for the mitochondria
Correct Answer: A
Explanation: The light-dependent reactions occur in the thylakoid membranes of the
chloroplast where sunlight is captured by chlorophyll. This energy is used to split water
molecules and excite electrons, eventually producing ATP and NADPH. These two
molecules provide the necessary chemical energy and reducing power for the subsequent
Calvin Cycle.
3. According to the principles of Mendelian genetics, what is the expected phenotypic ratio of
a cross between two individuals heterozygous for a single trait (Aa x Aa)?
A. 1:1
B. 1:2:1
C. 9:3:3:1
D. 3:1
,Correct Answer: D
Explanation: In a monohybrid cross between two heterozygotes, the genotypic ratio is
typically 1:2:1 (AA:Aa:aa). However, because the dominant allele masks the recessive one,
both the homozygous dominant and heterozygous individuals display the same phenotype.
This results in a phenotypic ratio where 75% show the dominant trait and 25% show the
recessive trait, or 3:1.
4. Which organelle is responsible for the synthesis of proteins that are destined for secretion
or membrane insertion?
A. Smooth Endoplasmic Reticulum
B. Lysosome
C. Rough Endoplasmic Reticulum
D. Peroxisome
Correct Answer: C
Explanation: The Rough Endoplasmic Reticulum (RER) is studded with ribosomes, which
are the sites of protein synthesis. As these ribosomes translate mRNA, the resulting
polypeptides are threaded into the RER lumen for folding and modification. This specific
pathway is utilized for proteins that will eventually be sent to the Golgi apparatus for
further sorting to the cell exterior or membrane.
5. During which phase of the cell cycle is DNA replicated to ensure each daughter cell receives
a full complement of genetic material?
A. S phase
B. G1 phase
C. G2 phase
D. M phase
Correct Answer: A
Explanation: The cell cycle consists of Interphase and the Mitotic phase. Interphase is
further divided into G1 (growth), S (synthesis), and G2 (preparation for division). DNA
replication occurs specifically during the S phase, ensuring that every chromosome is
duplicated into two sister chromatids before mitosis begins.
6. Which nitrogenous base is found in RNA but not in DNA?
A. Uracil
B. Adenine
C. Thymine
, D. Guanine
Correct Answer: A
Explanation: DNA and RNA share three nitrogenous bases: Adenine, Cytosine, and
Guanine. DNA uniquely uses Thymine to pair with Adenine. In contrast, RNA utilizes Uracil
in place of Thymine, which allows for different structural interactions and stability levels
suitable for temporary genetic messaging.
7. In cellular respiration, where does the Electron Transport Chain (ETC) take place within a
eukaryotic cell?
A. Inner mitochondrial membrane
B. Mitochondrial matrix
C. Cytoplasm
D. Chloroplast stroma
Correct Answer: A
Explanation: The Electron Transport Chain is the final stage of aerobic cellular respiration.
It consists of a series of protein complexes located on the cristae, or inner folds, of the
mitochondrial membrane. This location is critical because it allows for the establishment of
a proton gradient between the matrix and the intermembrane space, which drives ATP
synthesis.
8. What is the role of an enzyme in a biological chemical reaction?
A. To increase the total amount of energy released by the reaction
B. To lower the activation energy required for the reaction to proceed
C. To serve as a reactant that is consumed during the process
D. To prevent the reaction from occurring spontaneously
Correct Answer: B
Explanation: Enzymes are biological catalysts that speed up chemical reactions by
providing an alternative pathway with a lower activation energy. They bind specifically to
substrates at an active site, facilitating the transition state without being permanently
altered themselves. This efficiency allows life-sustaining reactions to occur rapidly at body
temperatures.
9. Which process results in four non-identical haploid daughter cells?
A. Mitosis
B. Meiosis
C. Binary Fission
with Rationale (BIOL101 Final Exam) | Liberty University
1. Which of the following best describes the structural component of a cell membrane that
allows it to be fluid yet stable?
A. A phospholipid bilayer with embedded proteins and cholesterol
B. A rigid layer of cellulose
C. A solid wall of chitin and mineral salts
D. A single layer of glycoproteins
Correct Answer: A
Explanation: The cell membrane is composed of a phospholipid bilayer which provides a
flexible matrix. Proteins are embedded within this layer to facilitate transport and
signaling, while cholesterol molecules help regulate fluidity at different temperatures. This
‘fluid mosaic model’ is essential for maintaining the cell’s integrity while allowing for the
movement of essential materials.
2. In the process of photosynthesis, what is the primary purpose of the Light-Dependent
Reactions?
A. To convert light energy into chemical energy in the form of ATP and NADPH
B. To produce water as a byproduct for the plant
C. To fix carbon dioxide into glucose molecules
D. To breakdown glucose into pyruvate for the mitochondria
Correct Answer: A
Explanation: The light-dependent reactions occur in the thylakoid membranes of the
chloroplast where sunlight is captured by chlorophyll. This energy is used to split water
molecules and excite electrons, eventually producing ATP and NADPH. These two
molecules provide the necessary chemical energy and reducing power for the subsequent
Calvin Cycle.
3. According to the principles of Mendelian genetics, what is the expected phenotypic ratio of
a cross between two individuals heterozygous for a single trait (Aa x Aa)?
A. 1:1
B. 1:2:1
C. 9:3:3:1
D. 3:1
,Correct Answer: D
Explanation: In a monohybrid cross between two heterozygotes, the genotypic ratio is
typically 1:2:1 (AA:Aa:aa). However, because the dominant allele masks the recessive one,
both the homozygous dominant and heterozygous individuals display the same phenotype.
This results in a phenotypic ratio where 75% show the dominant trait and 25% show the
recessive trait, or 3:1.
4. Which organelle is responsible for the synthesis of proteins that are destined for secretion
or membrane insertion?
A. Smooth Endoplasmic Reticulum
B. Lysosome
C. Rough Endoplasmic Reticulum
D. Peroxisome
Correct Answer: C
Explanation: The Rough Endoplasmic Reticulum (RER) is studded with ribosomes, which
are the sites of protein synthesis. As these ribosomes translate mRNA, the resulting
polypeptides are threaded into the RER lumen for folding and modification. This specific
pathway is utilized for proteins that will eventually be sent to the Golgi apparatus for
further sorting to the cell exterior or membrane.
5. During which phase of the cell cycle is DNA replicated to ensure each daughter cell receives
a full complement of genetic material?
A. S phase
B. G1 phase
C. G2 phase
D. M phase
Correct Answer: A
Explanation: The cell cycle consists of Interphase and the Mitotic phase. Interphase is
further divided into G1 (growth), S (synthesis), and G2 (preparation for division). DNA
replication occurs specifically during the S phase, ensuring that every chromosome is
duplicated into two sister chromatids before mitosis begins.
6. Which nitrogenous base is found in RNA but not in DNA?
A. Uracil
B. Adenine
C. Thymine
, D. Guanine
Correct Answer: A
Explanation: DNA and RNA share three nitrogenous bases: Adenine, Cytosine, and
Guanine. DNA uniquely uses Thymine to pair with Adenine. In contrast, RNA utilizes Uracil
in place of Thymine, which allows for different structural interactions and stability levels
suitable for temporary genetic messaging.
7. In cellular respiration, where does the Electron Transport Chain (ETC) take place within a
eukaryotic cell?
A. Inner mitochondrial membrane
B. Mitochondrial matrix
C. Cytoplasm
D. Chloroplast stroma
Correct Answer: A
Explanation: The Electron Transport Chain is the final stage of aerobic cellular respiration.
It consists of a series of protein complexes located on the cristae, or inner folds, of the
mitochondrial membrane. This location is critical because it allows for the establishment of
a proton gradient between the matrix and the intermembrane space, which drives ATP
synthesis.
8. What is the role of an enzyme in a biological chemical reaction?
A. To increase the total amount of energy released by the reaction
B. To lower the activation energy required for the reaction to proceed
C. To serve as a reactant that is consumed during the process
D. To prevent the reaction from occurring spontaneously
Correct Answer: B
Explanation: Enzymes are biological catalysts that speed up chemical reactions by
providing an alternative pathway with a lower activation energy. They bind specifically to
substrates at an active site, facilitating the transition state without being permanently
altered themselves. This efficiency allows life-sustaining reactions to occur rapidly at body
temperatures.
9. Which process results in four non-identical haploid daughter cells?
A. Mitosis
B. Meiosis
C. Binary Fission
