BIOD 101 / BIOD101 Essential Biology I with Lab Exam
Actual 2025/2026 with Detailed Rationales | 100%
Verified | Pass Guaranteed – A+ Graded
SECTION 1: CELLULAR STRUCTURE & FUNCTION (Q1–Q12)
Q1: Which organelle is responsible for synthesizing proteins destined for secretion
from the cell?
A. Lysosome
B. Peroxisome
C. Rough endoplasmic reticulum
D. Smooth endoplasmic reticulum
Correct Answer: C
Rationale: Correct because ribosomes on the rough ER synthesize proteins that enter
the lumen for post-translational modification, folding, and transport to the Golgi
apparatus for secretion.
Q2: Which structure is found in prokaryotic cells but absent in eukaryotic cells?
A. Ribosomes
B. Plasma membrane
C. Nucleoid region
D. Mitochondria
Correct Answer: C
Rationale: Correct because prokaryotes lack a membrane-bound nucleus and instead
contain a nucleoid region where their circular chromosome is localized;
mitochondria are present only in eukaryotes.
Q3: The cytoskeleton of eukaryotic cells is composed of which three main filament
types?
A. DNA, RNA, and proteins
B. Microfilaments, intermediate filaments, and microtubules
C. Cellulose, chitin, and peptidoglycan
D. Phospholipids, cholesterol, and proteins
Correct Answer: C
, Rationale: Correct because the eukaryotic cytoskeleton consists of microfilaments
(actin), intermediate filaments (keratins, vimentin, lamins), and microtubules
(tubulin), which provide structural support and enable cell motility.
Q4: Which organelle contains hydrolytic enzymes capable of breaking down
macromolecules and damaged organelles?
A. Golgi apparatus
B. Lysosome
C. Ribosome
D. Nucleolus
Correct Answer: C
Rationale: Correct because lysosomes are membrane-bound organelles containing
acid hydrolases that degrade worn-out organelles, engulfed particles, and
macromolecules in the acidic intracellular environment.
Q5: In plant cells, which organelle is responsible for photosynthesis?
A. Mitochondrion
B. Chloroplast
C. Vacuole
D. Peroxisome
Correct Answer: C
Rationale: Correct because chloroplasts contain chlorophyll and the thylakoid
membrane systems where the light-dependent reactions of photosynthesis occur,
converting light energy into chemical energy.
Q6: Which cellular structure is the primary site of ATP synthesis through oxidative
phosphorylation?
A. Cytoplasm
B. Mitochondrion
C. Nucleus
D. Golgi apparatus
Correct Answer: C
Rationale: Correct because mitochondria house the electron transport chain and ATP
synthase on their inner membrane, where the proton-motive force drives ATP
synthesis during cellular respiration.
Q7: The nuclear envelope of eukaryotic cells is characterized by which feature?
A. It is a single membrane continuous with the plasma membrane.
Actual 2025/2026 with Detailed Rationales | 100%
Verified | Pass Guaranteed – A+ Graded
SECTION 1: CELLULAR STRUCTURE & FUNCTION (Q1–Q12)
Q1: Which organelle is responsible for synthesizing proteins destined for secretion
from the cell?
A. Lysosome
B. Peroxisome
C. Rough endoplasmic reticulum
D. Smooth endoplasmic reticulum
Correct Answer: C
Rationale: Correct because ribosomes on the rough ER synthesize proteins that enter
the lumen for post-translational modification, folding, and transport to the Golgi
apparatus for secretion.
Q2: Which structure is found in prokaryotic cells but absent in eukaryotic cells?
A. Ribosomes
B. Plasma membrane
C. Nucleoid region
D. Mitochondria
Correct Answer: C
Rationale: Correct because prokaryotes lack a membrane-bound nucleus and instead
contain a nucleoid region where their circular chromosome is localized;
mitochondria are present only in eukaryotes.
Q3: The cytoskeleton of eukaryotic cells is composed of which three main filament
types?
A. DNA, RNA, and proteins
B. Microfilaments, intermediate filaments, and microtubules
C. Cellulose, chitin, and peptidoglycan
D. Phospholipids, cholesterol, and proteins
Correct Answer: C
, Rationale: Correct because the eukaryotic cytoskeleton consists of microfilaments
(actin), intermediate filaments (keratins, vimentin, lamins), and microtubules
(tubulin), which provide structural support and enable cell motility.
Q4: Which organelle contains hydrolytic enzymes capable of breaking down
macromolecules and damaged organelles?
A. Golgi apparatus
B. Lysosome
C. Ribosome
D. Nucleolus
Correct Answer: C
Rationale: Correct because lysosomes are membrane-bound organelles containing
acid hydrolases that degrade worn-out organelles, engulfed particles, and
macromolecules in the acidic intracellular environment.
Q5: In plant cells, which organelle is responsible for photosynthesis?
A. Mitochondrion
B. Chloroplast
C. Vacuole
D. Peroxisome
Correct Answer: C
Rationale: Correct because chloroplasts contain chlorophyll and the thylakoid
membrane systems where the light-dependent reactions of photosynthesis occur,
converting light energy into chemical energy.
Q6: Which cellular structure is the primary site of ATP synthesis through oxidative
phosphorylation?
A. Cytoplasm
B. Mitochondrion
C. Nucleus
D. Golgi apparatus
Correct Answer: C
Rationale: Correct because mitochondria house the electron transport chain and ATP
synthase on their inner membrane, where the proton-motive force drives ATP
synthesis during cellular respiration.
Q7: The nuclear envelope of eukaryotic cells is characterized by which feature?
A. It is a single membrane continuous with the plasma membrane.
