2026 BIOD 101 Module 3 Final Exam – 2026 | Portage Learning |
Complete Verified Q&As + Review Guide
The second half of our 100-question series for Module 3. This 2026 update dives
into Epigenetics, Operon Systems, PCR Technology, Gel Electrophoresis, and Non-
Mendelian Inheritance (Incomplete Dominance/Codominance). Essential for students pursuing
advanced healthcare degrees
1. Which scientist(s) are credited with discovering the double-helix structure of
DNA?
A. Gregor Mendel
B. Watson and Crick
C. Louis Pasteur
D. Charles Darwin
Rationale: Watson and Crick (using data from Rosalind Franklin) published the first
accurate model of the DNA double helix in 1953.
2. The building blocks of DNA are called:
A. Amino Acids
B. Nucleotides
C. Monosaccharides
D. Fatty Acids
Rationale: A Nucleotide consists of a nitrogenous base, a five-carbon sugar
(deoxyribose), and a phosphate group.
3. In a DNA molecule, Adenine (A) always pairs with:
A. Guanine (G)
B. Cytosine (C)
C. Thymine (T)
D. Uracil (U)
Rationale: According to Chargaff's Rules, Adenine pairs with Thymine via two
hydrogen bonds.
4. Which of the following is a key difference between DNA and RNA?
A. DNA is single-stranded; RNA is double-stranded.
B. DNA contains Deoxyribose; RNA contains Ribose.
C. DNA uses Uracil; RNA uses Thymine.
D. DNA stays in the ribosome; RNA stays in the nucleus.
,Rationale: RNA contains the sugar ribose and the base Uracil, while DNA uses
deoxyribose and Thymine.
5. The process of copying a DNA strand into a complementary mRNA strand is
called:
A. Translation
B. Transcription
C. Replication
D. Mutation
Rationale: Transcription occurs in the nucleus where DNA serves as a template to
create messenger RNA (mRNA).
6. Where does Translation occur within the cell?
A. Nucleus
B. Mitochondria
C. Ribosome
D. Lysosome
Rationale: Translation (protein synthesis) happens in the cytoplasm at the ribosome,
where mRNA is read to build a polypeptide chain.
7. A "Codon" is a sequence of how many nucleotides?
A. 1
B. 2
C. 3
D. 4
Rationale: Each Codon (triplet) codes for one specific amino acid.
8. Which enzyme is responsible for unwinding the DNA double helix during
replication?
A. DNA Polymerase
B. Helicase
C. Ligase
D. RNA Polymerase
Rationale: Helicase "unzips" the hydrogen bonds between base pairs to create a
replication fork.
9. In genetics, an organism's physical appearance is its:
A. Genotype
B. Phenotype
C. Allele
D. Pedigree
, Rationale: Phenotype refers to observable traits (e.g., blue eyes), whereas Genotype
refers to the genetic makeup (e.g., bb).
10. If an individual has two different alleles for a trait (e.g., Tt), they are:
A. Homozygous dominant
B. Homozygous recessive
C. Heterozygous
D. Hemizygous
Rationale: Hetero- means different; the individual carries both a dominant and a
recessive allele.
11. Which phase of Mitosis involves the chromosomes lining up in the center of
the cell?
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Rationale: During Metaphase, spindle fibers pull chromosomes to the "metaphase
plate" or equator of the cell.
12. How many daughter cells are produced at the end of Meiosis?
A. 2 Identical cells
B. 4 Non-identical haploid cells
C. 2 Non-identical diploid cells
D. 4 Identical diploid cells
Rationale: Meiosis results in four genetically unique gametes (sperm or egg) with half
the original chromosome count.
13. The "Start Codon" for every mRNA transcript is:
A. UAA
B. AUG
C. UGA
D. GGG
Rationale: AUG codes for the amino acid Methionine and signals the ribosome to begin
translation.
14. What type of bond holds the two strands of DNA together?
A. Ionic Bond
B. Covalent Bond
C. Hydrogen Bond
D. Peptide Bond
Complete Verified Q&As + Review Guide
The second half of our 100-question series for Module 3. This 2026 update dives
into Epigenetics, Operon Systems, PCR Technology, Gel Electrophoresis, and Non-
Mendelian Inheritance (Incomplete Dominance/Codominance). Essential for students pursuing
advanced healthcare degrees
1. Which scientist(s) are credited with discovering the double-helix structure of
DNA?
A. Gregor Mendel
B. Watson and Crick
C. Louis Pasteur
D. Charles Darwin
Rationale: Watson and Crick (using data from Rosalind Franklin) published the first
accurate model of the DNA double helix in 1953.
2. The building blocks of DNA are called:
A. Amino Acids
B. Nucleotides
C. Monosaccharides
D. Fatty Acids
Rationale: A Nucleotide consists of a nitrogenous base, a five-carbon sugar
(deoxyribose), and a phosphate group.
3. In a DNA molecule, Adenine (A) always pairs with:
A. Guanine (G)
B. Cytosine (C)
C. Thymine (T)
D. Uracil (U)
Rationale: According to Chargaff's Rules, Adenine pairs with Thymine via two
hydrogen bonds.
4. Which of the following is a key difference between DNA and RNA?
A. DNA is single-stranded; RNA is double-stranded.
B. DNA contains Deoxyribose; RNA contains Ribose.
C. DNA uses Uracil; RNA uses Thymine.
D. DNA stays in the ribosome; RNA stays in the nucleus.
,Rationale: RNA contains the sugar ribose and the base Uracil, while DNA uses
deoxyribose and Thymine.
5. The process of copying a DNA strand into a complementary mRNA strand is
called:
A. Translation
B. Transcription
C. Replication
D. Mutation
Rationale: Transcription occurs in the nucleus where DNA serves as a template to
create messenger RNA (mRNA).
6. Where does Translation occur within the cell?
A. Nucleus
B. Mitochondria
C. Ribosome
D. Lysosome
Rationale: Translation (protein synthesis) happens in the cytoplasm at the ribosome,
where mRNA is read to build a polypeptide chain.
7. A "Codon" is a sequence of how many nucleotides?
A. 1
B. 2
C. 3
D. 4
Rationale: Each Codon (triplet) codes for one specific amino acid.
8. Which enzyme is responsible for unwinding the DNA double helix during
replication?
A. DNA Polymerase
B. Helicase
C. Ligase
D. RNA Polymerase
Rationale: Helicase "unzips" the hydrogen bonds between base pairs to create a
replication fork.
9. In genetics, an organism's physical appearance is its:
A. Genotype
B. Phenotype
C. Allele
D. Pedigree
, Rationale: Phenotype refers to observable traits (e.g., blue eyes), whereas Genotype
refers to the genetic makeup (e.g., bb).
10. If an individual has two different alleles for a trait (e.g., Tt), they are:
A. Homozygous dominant
B. Homozygous recessive
C. Heterozygous
D. Hemizygous
Rationale: Hetero- means different; the individual carries both a dominant and a
recessive allele.
11. Which phase of Mitosis involves the chromosomes lining up in the center of
the cell?
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Rationale: During Metaphase, spindle fibers pull chromosomes to the "metaphase
plate" or equator of the cell.
12. How many daughter cells are produced at the end of Meiosis?
A. 2 Identical cells
B. 4 Non-identical haploid cells
C. 2 Non-identical diploid cells
D. 4 Identical diploid cells
Rationale: Meiosis results in four genetically unique gametes (sperm or egg) with half
the original chromosome count.
13. The "Start Codon" for every mRNA transcript is:
A. UAA
B. AUG
C. UGA
D. GGG
Rationale: AUG codes for the amino acid Methionine and signals the ribosome to begin
translation.
14. What type of bond holds the two strands of DNA together?
A. Ionic Bond
B. Covalent Bond
C. Hydrogen Bond
D. Peptide Bond
