PCB 3023 Exam 1 Quiz 1,2 & 3 |
Questions and Answers with Complete
Rationale | Latest Update 2026/2027
Question 1
What is the major site for ATP production in eukaryotic cells?
A. Mitochondria
B. Nucleus
C. Cytosol
D. Endoplasmic Reticulum
E. Peroxisome
Correct Answer: A. Mitochondria
Rationale: Mitochondria are known as the "powerhouses" of eukaryotic cells
because they house the electron transport chain and ATP synthase complexes in
their inner mitochondrial membrane. Through oxidative phosphorylation,
mitochondria generate the vast majority of cellular ATP (approximately 90-95%).
The cytosol contributes some ATP through glycolysis, but this is far less efficient
than mitochondrial ATP production.
Question 2
Where does transcription occur in a eukaryotic cell?
A. Cell membrane
B. Nucleus
C. Cytoplasm
D. Golgi
E. ER
Correct Answer: B. Nucleus
, Rationale: In eukaryotic cells, transcription (the synthesis of RNA from a DNA
template) occurs within the nucleus because this is where the genomic DNA is
housed. This spatial separation between transcription (nucleus) and translation
(cytoplasm) is a defining feature of eukaryotes, allowing for post-transcriptional
modifications such as splicing, capping, and polyadenylation before mRNA is
exported to the cytoplasm.
Question 3
Which of the following features of eukaryotes are believed to have originated
from the engulfing of a prokaryotic cell?
A. Mitochondria
B. Chloroplasts
C. Peroxisomes
D. Mitochondria and chloroplasts
E. Cytoskeleton
Correct Answer: D. Mitochondria and chloroplasts
Rationale: The endosymbiotic theory proposes that mitochondria and
chloroplasts originated from free-living prokaryotic organisms that were engulfed
by ancestral eukaryotic cells. Evidence supporting this includes their own circular
DNA, double membranes (consistent with phagocytosis), 70S ribosomes (similar
to bacteria), and binary fission division. Chloroplasts likely evolved from
cyanobacteria, while mitochondria evolved from α-proteobacteria.
Question 4
Protein synthesis takes place in the _____.
A. Nucleus
B. Mitochondria
C. ER
D. Cytosol
E. b, c and d
Questions and Answers with Complete
Rationale | Latest Update 2026/2027
Question 1
What is the major site for ATP production in eukaryotic cells?
A. Mitochondria
B. Nucleus
C. Cytosol
D. Endoplasmic Reticulum
E. Peroxisome
Correct Answer: A. Mitochondria
Rationale: Mitochondria are known as the "powerhouses" of eukaryotic cells
because they house the electron transport chain and ATP synthase complexes in
their inner mitochondrial membrane. Through oxidative phosphorylation,
mitochondria generate the vast majority of cellular ATP (approximately 90-95%).
The cytosol contributes some ATP through glycolysis, but this is far less efficient
than mitochondrial ATP production.
Question 2
Where does transcription occur in a eukaryotic cell?
A. Cell membrane
B. Nucleus
C. Cytoplasm
D. Golgi
E. ER
Correct Answer: B. Nucleus
, Rationale: In eukaryotic cells, transcription (the synthesis of RNA from a DNA
template) occurs within the nucleus because this is where the genomic DNA is
housed. This spatial separation between transcription (nucleus) and translation
(cytoplasm) is a defining feature of eukaryotes, allowing for post-transcriptional
modifications such as splicing, capping, and polyadenylation before mRNA is
exported to the cytoplasm.
Question 3
Which of the following features of eukaryotes are believed to have originated
from the engulfing of a prokaryotic cell?
A. Mitochondria
B. Chloroplasts
C. Peroxisomes
D. Mitochondria and chloroplasts
E. Cytoskeleton
Correct Answer: D. Mitochondria and chloroplasts
Rationale: The endosymbiotic theory proposes that mitochondria and
chloroplasts originated from free-living prokaryotic organisms that were engulfed
by ancestral eukaryotic cells. Evidence supporting this includes their own circular
DNA, double membranes (consistent with phagocytosis), 70S ribosomes (similar
to bacteria), and binary fission division. Chloroplasts likely evolved from
cyanobacteria, while mitochondria evolved from α-proteobacteria.
Question 4
Protein synthesis takes place in the _____.
A. Nucleus
B. Mitochondria
C. ER
D. Cytosol
E. b, c and d
