BIOL 101 Quiz 3 V3 | BIOL 101 Principles of
Biology | Actual Q&A with Rationale (BIOL101 Quiz
3) | Liberty University
1. During which specific phase of the eukaryotic cell cycle is the genetic material duplicated?
A. M phase
B. G1 phase
C. G2 phase
D. S phase
Correct Answer: D
Explanation: The S phase, or synthesis phase, is the specific period during interphase
when DNA replication occurs. This process ensures that the cell contains two complete sets
of chromosomes before entering mitosis. Proper synthesis is critical for maintaining
genetic stability across subsequent generations of cells.
2. Which enzyme is responsible for unwinding the DNA double helix during the process of
replication?
A. DNA Ligase
B. DNA Polymerase
C. Helicase
D. Primase
,Correct Answer: C
Explanation: Helicase acts by breaking the hydrogen bonds between the nitrogenous base
pairs of the DNA strands. This unwinding creates the replication fork where other enzymes
can begin their work. Without helicase, the double-stranded DNA would remain tightly
coiled and inaccessible for replication.
3. In Mendelian genetics, what is the expected phenotypic ratio of an F2 generation resulting
from a monohybrid cross of two true-breeding parents?
A. 3:1
B. 1:2:1
C. 9:3:3:1
D. 1:1
Correct Answer: A
Explanation: A monohybrid cross between two heterozygotes typically yields a 3:1
phenotypic ratio where three-fourths display the dominant trait and one-fourth display the
recessive trait. This observation led Gregor Mendel to formulate the Law of Segregation.
The underlying genotypic ratio for this cross is actually 1:2:1.
4. Which of the following describes the correct flow of genetic information according to the
central dogma of molecular biology?
A. DNA to RNA to Protein
B. DNA to Protein to RNA
, C. RNA to DNA to Protein
D. Protein to RNA to DNA
Correct Answer: A
Explanation: The central dogma describes the two-step process, transcription and
translation, by which the information in genes flows into proteins. Transcription converts
DNA into a messenger RNA intermediate. Translation then uses the mRNA sequence to
assemble the corresponding amino acids into a polypeptide chain.
5. In humans, how many chromosomes are found in a gamete produced through the process
of meiosis?
A. 46
B. 12
C. 92
D. 23
Correct Answer: D
Explanation: Gametes are haploid cells, meaning they contain only one set of
chromosomes. In humans, the diploid number is 46, so the resulting gametes must contain
exactly 23 chromosomes. This reduction is essential so that the diploid number is restored
upon fertilization.
Biology | Actual Q&A with Rationale (BIOL101 Quiz
3) | Liberty University
1. During which specific phase of the eukaryotic cell cycle is the genetic material duplicated?
A. M phase
B. G1 phase
C. G2 phase
D. S phase
Correct Answer: D
Explanation: The S phase, or synthesis phase, is the specific period during interphase
when DNA replication occurs. This process ensures that the cell contains two complete sets
of chromosomes before entering mitosis. Proper synthesis is critical for maintaining
genetic stability across subsequent generations of cells.
2. Which enzyme is responsible for unwinding the DNA double helix during the process of
replication?
A. DNA Ligase
B. DNA Polymerase
C. Helicase
D. Primase
,Correct Answer: C
Explanation: Helicase acts by breaking the hydrogen bonds between the nitrogenous base
pairs of the DNA strands. This unwinding creates the replication fork where other enzymes
can begin their work. Without helicase, the double-stranded DNA would remain tightly
coiled and inaccessible for replication.
3. In Mendelian genetics, what is the expected phenotypic ratio of an F2 generation resulting
from a monohybrid cross of two true-breeding parents?
A. 3:1
B. 1:2:1
C. 9:3:3:1
D. 1:1
Correct Answer: A
Explanation: A monohybrid cross between two heterozygotes typically yields a 3:1
phenotypic ratio where three-fourths display the dominant trait and one-fourth display the
recessive trait. This observation led Gregor Mendel to formulate the Law of Segregation.
The underlying genotypic ratio for this cross is actually 1:2:1.
4. Which of the following describes the correct flow of genetic information according to the
central dogma of molecular biology?
A. DNA to RNA to Protein
B. DNA to Protein to RNA
, C. RNA to DNA to Protein
D. Protein to RNA to DNA
Correct Answer: A
Explanation: The central dogma describes the two-step process, transcription and
translation, by which the information in genes flows into proteins. Transcription converts
DNA into a messenger RNA intermediate. Translation then uses the mRNA sequence to
assemble the corresponding amino acids into a polypeptide chain.
5. In humans, how many chromosomes are found in a gamete produced through the process
of meiosis?
A. 46
B. 12
C. 92
D. 23
Correct Answer: D
Explanation: Gametes are haploid cells, meaning they contain only one set of
chromosomes. In humans, the diploid number is 46, so the resulting gametes must contain
exactly 23 chromosomes. This reduction is essential so that the diploid number is restored
upon fertilization.
