Q&A | Portage Learning
Here are 100 original NCLEX-style practice questions for BIOD 101 Module 3 | Essential
Biology I. These questions cover DNA structure and replication, gene expression, cell
division, Mendelian genetics, mutations, genetic disorders, cancer genetics,
biotechnology, genetic testing, and clinical applications.
Question 1:
A nurse is teaching a client about DNA replication. Which statement best describes
semi-conservative replication?
A. Both strands of the original DNA molecule are destroyed.
B. Each new DNA molecule contains one original strand and one new strand.
C. Only RNA is copied during replication.
D. Proteins are copied directly from DNA.
Correct answer: B
Rationale:
DNA replication is semi-conservative. Each new DNA molecule consists of one original
parental strand and one newly synthesized daughter strand.
Question 2:
A client asks which nitrogenous base pairs with adenine in DNA.
A. Guanine
B. Cytosine
C. Thymine
D. Uracil
Correct answer: C
Rationale:
In DNA, adenine pairs with thymine via two hydrogen bonds. In RNA, adenine pairs with
uracil.
Question 3:
Which base pairs with adenine in RNA?
,A. Thymine
B. Uracil
C. Guanine
D. Cytosine
Correct answer: B
Rationale:
RNA contains uracil instead of thymine. Adenine pairs with uracil in RNA.
Question 4:
A nurse is explaining where transcription occurs in a eukaryotic cell.
A. Ribosome
B. Cytoplasm
C. Nucleus
D. Mitochondria
Correct answer: C
Rationale:
Transcription, the synthesis of mRNA from DNA, occurs in the nucleus of eukaryotic
cells.
Question 5:
Where does translation occur?
A. Nucleus
B. Ribosome
C. Golgi apparatus
D. Lysosome
Correct answer: B
Rationale:
Translation occurs at the ribosome, where mRNA is decoded into a polypeptide chain.
Question 6:
Which molecule carries the genetic message from DNA to the ribosome?
A. tRNA
B. mRNA
,C. rRNA
D. DNA polymerase
Correct answer: B
Rationale:
Messenger RNA (mRNA) carries the genetic code from DNA to the ribosome.
Question 7:
Which molecule brings amino acids to the ribosome during translation?
A. mRNA
B. tRNA
C. rRNA
D. DNA
Correct answer: B
Rationale:
Transfer RNA (tRNA) delivers specific amino acids to the ribosome based on codon-
anticodon pairing.
Question 8:
Which molecule is a structural component of the ribosome?
A. mRNA
B. tRNA
C. rRNA
D. DNA
Correct answer: C
Rationale:
Ribosomal RNA (rRNA) combines with proteins to form ribosomes, the site of protein
synthesis.
Question 9:
A three-base sequence on mRNA that codes for an amino acid is called a:
A. Anticodon
B. Codon
C. Gene
D. Promoter
, Correct answer: B
Rationale:
A codon is a three-nucleotide sequence on mRNA that specifies an amino acid.
Question 10:
Which codon is the start codon for translation?
A. UAA
B. UAG
C. UGA
D. AUG
Correct answer: D
Rationale:
AUG is the start codon and codes for methionine, initiating translation.
Question 11:
Which of the following is a stop codon?
A. AUG
B. UAA
C. GUA
D. CAU
Correct answer: B
Rationale:
UAA, UAG, and UGA are stop codons that terminate translation.
Question 12:
Which enzyme unwinds the DNA double helix during replication?
A. DNA polymerase
B. Helicase
C. Ligase
D. RNA polymerase
Correct answer: B