BIOLOGY 5236 PRACTICE EXAM STUDY
GUIDE 2025/2026 ACCURATE QUESTIONS
AND CORRECT DETAILED ANSWERS
WITH RATIONALES || 100% GUARANTEED
PASS <LATEST VERSION>
1
Which organelle is the primary site of ATP production in eukaryotic cells?
A. Golgi apparatus
✅
B. Lysosome
C. Mitochondrion
D. Endoplasmic reticulum
Rationale: Mitochondria perform oxidative phosphorylation, producing most cellular ATP.
2
DNA replication is described as semiconservative because:
A. New strands are built from free nucleotides only
✅
B. Both new strands are conservative copies
C. Each daughter DNA contains one parental strand and one new strand
D. DNA is replicated without any parental template
Rationale: Each double helix after replication has one old and one newly synthesized strand.
3
,Which base pairing is held by two hydrogen bonds?
✅
A. Cytosine–Guanine
B. Adenine–Thymine
C. Guanine–Uracil
D. Adenine–Cytosine
Rationale: A–T (or A–U in RNA) pairs form two hydrogen bonds; C–G forms three.
4
What enzyme synthesizes RNA primers during DNA replication?
A. DNA polymerase I
B. DNA ligase
✅
C. Helicase
D. Primase
Rationale: Primase (an RNA polymerase) lays short RNA primers for DNA polymerases.
5
Which phase of mitosis is characterized by alignment of chromosomes on the metaphase plate?
A. Prophase
✅
B. Anaphase
C. Metaphase
D. Telophase
Rationale: Metaphase features chromosomes lined at the cell equator.
6
In Hardy–Weinberg equilibrium, which of the following is assumed?
A. Non-random mating
✅
B. Strong selection
C. No migration
D. Small population size
Rationale: HW requires large population, random mating, no selection, no migration, no
mutation.
7
, A frameshift mutation usually results from:
✅
A. Point substitution
B. Insertion or deletion of nucleotides not in multiples of three
C. Silent mutation
D. Conservative substitution
Rationale: Insertions/deletions shift reading frame unless in multiples of three.
8
Which of these is a monosaccharide?
A. Sucrose
✅
B. Lactose
C. Glucose
D. Starch
Rationale: Glucose is a simple sugar (monosaccharide); sucrose/lactose are disaccharides.
9
The primary structure of a protein describes:
✅
A. Tertiary folding
B. Amino acid sequence
C. Alpha helices and beta sheets
D. Subunit arrangement
Rationale: Primary structure = linear sequence of amino acids.
10
An example of an essential amino acid (cannot be synthesized de novo in humans) is:
✅
A. Alanine
B. Leucine
C. Glycine
D. Serine
Rationale: Leucine is essential; alanine, glycine, serine are non-essential.
11
GUIDE 2025/2026 ACCURATE QUESTIONS
AND CORRECT DETAILED ANSWERS
WITH RATIONALES || 100% GUARANTEED
PASS <LATEST VERSION>
1
Which organelle is the primary site of ATP production in eukaryotic cells?
A. Golgi apparatus
✅
B. Lysosome
C. Mitochondrion
D. Endoplasmic reticulum
Rationale: Mitochondria perform oxidative phosphorylation, producing most cellular ATP.
2
DNA replication is described as semiconservative because:
A. New strands are built from free nucleotides only
✅
B. Both new strands are conservative copies
C. Each daughter DNA contains one parental strand and one new strand
D. DNA is replicated without any parental template
Rationale: Each double helix after replication has one old and one newly synthesized strand.
3
,Which base pairing is held by two hydrogen bonds?
✅
A. Cytosine–Guanine
B. Adenine–Thymine
C. Guanine–Uracil
D. Adenine–Cytosine
Rationale: A–T (or A–U in RNA) pairs form two hydrogen bonds; C–G forms three.
4
What enzyme synthesizes RNA primers during DNA replication?
A. DNA polymerase I
B. DNA ligase
✅
C. Helicase
D. Primase
Rationale: Primase (an RNA polymerase) lays short RNA primers for DNA polymerases.
5
Which phase of mitosis is characterized by alignment of chromosomes on the metaphase plate?
A. Prophase
✅
B. Anaphase
C. Metaphase
D. Telophase
Rationale: Metaphase features chromosomes lined at the cell equator.
6
In Hardy–Weinberg equilibrium, which of the following is assumed?
A. Non-random mating
✅
B. Strong selection
C. No migration
D. Small population size
Rationale: HW requires large population, random mating, no selection, no migration, no
mutation.
7
, A frameshift mutation usually results from:
✅
A. Point substitution
B. Insertion or deletion of nucleotides not in multiples of three
C. Silent mutation
D. Conservative substitution
Rationale: Insertions/deletions shift reading frame unless in multiples of three.
8
Which of these is a monosaccharide?
A. Sucrose
✅
B. Lactose
C. Glucose
D. Starch
Rationale: Glucose is a simple sugar (monosaccharide); sucrose/lactose are disaccharides.
9
The primary structure of a protein describes:
✅
A. Tertiary folding
B. Amino acid sequence
C. Alpha helices and beta sheets
D. Subunit arrangement
Rationale: Primary structure = linear sequence of amino acids.
10
An example of an essential amino acid (cannot be synthesized de novo in humans) is:
✅
A. Alanine
B. Leucine
C. Glycine
D. Serine
Rationale: Leucine is essential; alanine, glycine, serine are non-essential.
11
