,BIOD 101 Module 6 Exam | Essential Biology I
w/Lab Exam Q&A | Portage Learning
1. The nucleoid region of a prokaryotic cell is best described as
A) a membrane-bound organelle containing linear chromosomes
B) a non-membrane-bound area where the circular chromosome is located
C) a structure that exports proteins out of the cell
D) a vesicle that stores metabolic enzymes
Correct Answer: a non-membrane-bound area where the circular chromosome
is located
Rationale: Prokaryotic DNA is not enclosed by a nuclear membrane; it
aggregates in the nucleoid region. This contrasts with the eukaryotic nucleus.
The DNA is typically a single circular chromosome. The nucleoid does not export
proteins or store enzymes.
2. Plasmids are small, circular DNA molecules in bacteria that often
A) carry genes for antibiotic resistance and can be transferred between cells
B) serve as the primary chromosome for all essential genes
C) are enclosed within a protein capsid
D) are responsible for ribosome synthesis
Correct Answer: carry genes for antibiotic resistance and can be transferred
between cells
,Rationale: Plasmids are extrachromosomal DNA that replicate independently.
They frequently encode resistance genes and can spread via conjugation. They
are not the main chromosome, nor are they involved in ribosome synthesis;
capsids are viral structures.
3. Prokaryotic ribosomes are structurally different from eukaryotic ribosomes
because they
A) are 80S and found free in the cytoplasm
B) are 70S and are not bound to any membrane
C) contain DNA as their main component
D) are larger and more complex
Correct Answer: are 70S and are not bound to any membrane
Rationale: Prokaryotic ribosomes are 70S (50S+30S subunits), whereas
eukaryotic cytoplasmic ribosomes are 80S. This difference allows antibiotics to
selectively target bacterial ribosomes. They are not membrane-bound and
consist of rRNA and protein, not DNA.
4. The bacterial plasma membrane functions in all of the following ways EXCEPT
A) acting as a selectively permeable barrier
B) providing a site for metabolic reactions such as respiration
C) synthesizing peptidoglycan for the cell wall
D) containing enzymes for ATP production in some species
Correct Answer: synthesizing peptidoglycan for the cell wall
, Rationale: Peptidoglycan synthesis occurs at the cell wall, not the plasma
membrane itself. The plasma membrane regulates transport, houses respiratory
enzymes in many bacteria, and maintains the proton gradient for ATP synthesis.
Peptidoglycan assembly involves membrane-bound carriers but the final
crosslinking is outside.
5. The rigid cell wall of bacteria is responsible for
A) DNA replication and segregation
B) maintaining cell shape and protecting against osmotic pressure
C) generating ATP via oxidative phosphorylation
D) synthesizing cytoplasmic proteins
Correct Answer: maintaining cell shape and protecting against osmotic pressure
Rationale: The peptidoglycan cell wall provides structural integrity, preventing
lysis in hypotonic environments. It determines bacterial shape (cocci, bacilli,
etc.). DNA replication, ATP generation, and protein synthesis occur in the
cytoplasm or at the membrane, not the wall.
6. A bacterial capsule contributes to virulence primarily by
A) enhancing flagellar rotation
B) facilitating DNA uptake during transformation
C) enabling adherence to surfaces and evasion of phagocytosis
D) synthesizing toxic proteins
Correct Answer: enabling adherence to surfaces and evasion of phagocytosis
w/Lab Exam Q&A | Portage Learning
1. The nucleoid region of a prokaryotic cell is best described as
A) a membrane-bound organelle containing linear chromosomes
B) a non-membrane-bound area where the circular chromosome is located
C) a structure that exports proteins out of the cell
D) a vesicle that stores metabolic enzymes
Correct Answer: a non-membrane-bound area where the circular chromosome
is located
Rationale: Prokaryotic DNA is not enclosed by a nuclear membrane; it
aggregates in the nucleoid region. This contrasts with the eukaryotic nucleus.
The DNA is typically a single circular chromosome. The nucleoid does not export
proteins or store enzymes.
2. Plasmids are small, circular DNA molecules in bacteria that often
A) carry genes for antibiotic resistance and can be transferred between cells
B) serve as the primary chromosome for all essential genes
C) are enclosed within a protein capsid
D) are responsible for ribosome synthesis
Correct Answer: carry genes for antibiotic resistance and can be transferred
between cells
,Rationale: Plasmids are extrachromosomal DNA that replicate independently.
They frequently encode resistance genes and can spread via conjugation. They
are not the main chromosome, nor are they involved in ribosome synthesis;
capsids are viral structures.
3. Prokaryotic ribosomes are structurally different from eukaryotic ribosomes
because they
A) are 80S and found free in the cytoplasm
B) are 70S and are not bound to any membrane
C) contain DNA as their main component
D) are larger and more complex
Correct Answer: are 70S and are not bound to any membrane
Rationale: Prokaryotic ribosomes are 70S (50S+30S subunits), whereas
eukaryotic cytoplasmic ribosomes are 80S. This difference allows antibiotics to
selectively target bacterial ribosomes. They are not membrane-bound and
consist of rRNA and protein, not DNA.
4. The bacterial plasma membrane functions in all of the following ways EXCEPT
A) acting as a selectively permeable barrier
B) providing a site for metabolic reactions such as respiration
C) synthesizing peptidoglycan for the cell wall
D) containing enzymes for ATP production in some species
Correct Answer: synthesizing peptidoglycan for the cell wall
, Rationale: Peptidoglycan synthesis occurs at the cell wall, not the plasma
membrane itself. The plasma membrane regulates transport, houses respiratory
enzymes in many bacteria, and maintains the proton gradient for ATP synthesis.
Peptidoglycan assembly involves membrane-bound carriers but the final
crosslinking is outside.
5. The rigid cell wall of bacteria is responsible for
A) DNA replication and segregation
B) maintaining cell shape and protecting against osmotic pressure
C) generating ATP via oxidative phosphorylation
D) synthesizing cytoplasmic proteins
Correct Answer: maintaining cell shape and protecting against osmotic pressure
Rationale: The peptidoglycan cell wall provides structural integrity, preventing
lysis in hypotonic environments. It determines bacterial shape (cocci, bacilli,
etc.). DNA replication, ATP generation, and protein synthesis occur in the
cytoplasm or at the membrane, not the wall.
6. A bacterial capsule contributes to virulence primarily by
A) enhancing flagellar rotation
B) facilitating DNA uptake during transformation
C) enabling adherence to surfaces and evasion of phagocytosis
D) synthesizing toxic proteins
Correct Answer: enabling adherence to surfaces and evasion of phagocytosis
