Cell and Molecular Biology Complete Exam Bank
With 2026 High Yield Questions and Detailed
Rationales for Medical and Graduate Students
Exam Overview
This comprehensive practice examination contains 300 questions
covering cell and molecular biology. The content is divided into five
major sections: Cell Structure and Organelles, Cell Membrane and
Transport, Cell Signaling and Communication, Cell Cycle and Division,
and Molecular Genetics and Gene Expression. Each question is
followed by a detailed rationale explaining the correct answer and why
the distractors are incorrect. This exam is designed to prepare students
for cell and molecular biology coursework and advanced studies.
Section One: Cell Structure and Organelles Questions 1 through 60
Question 1
The cell is the basic structural and functional unit of:
A) All living organisms
B) All prokaryotic organisms
C) All eukaryotic organisms
D) All multicellular organisms
Answer: A
Explanation: The cell is the basic structural and functional unit of all living
organisms. Cells are the smallest unit of life that can perform all life
processes. Prokaryotic and eukaryotic organisms are both composed of
cells.
Question 2
Prokaryotic cells are characterized by:
A) Absence of a true nucleus and membrane-bound organelles
B) Presence of a true nucleus and membrane-bound organelles
,
C) Presence of a cell wall composed of chitin
D) Presence of mitochondria and chloroplasts
Answer: A
Explanation: Prokaryotic cells are characterized by the absence of a true
nucleus and membrane-bound organelles. Their genetic material is not
enclosed within a nuclear membrane. Bacteria and archaea are prokaryotic
organisms.
Question 3
Eukaryotic cells are characterized by:
A) Presence of a true nucleus and membrane-bound organelles
B) Absence of a true nucleus and membrane-bound organelles
C) Presence of a cell wall composed of peptidoglycan
D) Absence of mitochondria and chloroplasts
Answer: A
Explanation: Eukaryotic cells are characterized by the presence of a true
nucleus and membrane-bound organelles. Their genetic material is enclosed
within a nuclear membrane. Animals, plants, fungi, and protists are
eukaryotic organisms.
Question 4
The nucleus contains which structures?
A) Chromatin, nucleolus, and nuclear envelope
B) Ribosomes, mitochondria, and endoplasmic reticulum
C) Golgi apparatus and lysosomes
D) Vacuoles and peroxisomes
Answer: A
Explanation: The nucleus contains chromatin, which is DNA and proteins,
the nucleolus, which is involved in ribosome assembly, and the nuclear
envelope, which surrounds the nucleus. Ribosomes and mitochondria are
not in the nucleus.
Question 5
,
The nucleolus is responsible for:
A) Ribosome assembly
B) Protein synthesis
C) DNA replication
D) Cell division
Answer: A
Explanation: The nucleolus is responsible for ribosome assembly. It
contains ribosomal RNA and proteins. Ribosomes are then transported to
the cytoplasm for protein synthesis.
Question 6
The nuclear envelope is composed of:
A) Two lipid bilayers with nuclear pores
B) A single lipid bilayer with nuclear pores
C) Two lipid bilayers without nuclear pores
D) A single lipid bilayer without nuclear pores
Answer: A
Explanation: The nuclear envelope is composed of two lipid bilayers with
nuclear pores. The nuclear pores allow the transport of molecules between
the nucleus and the cytoplasm. The outer membrane is continuous with the
endoplasmic reticulum.
Question 7
Ribosomes are responsible for:
A) Protein synthesis
B) Lipid synthesis
C) Carbohydrate synthesis
D) Nucleic acid synthesis
Answer: A
Explanation: Ribosomes are responsible for protein synthesis. They translate
messenger RNA into polypeptide chains. Ribosomes are composed of
ribosomal RNA and proteins.
,
Question 8
Ribosomes are composed of:
A) rRNA and proteins
B) DNA and proteins
C) mRNA and proteins
D) tRNA and proteins
Answer: A
Explanation: Ribosomes are composed of ribosomal RNA and proteins. The
rRNA provides the catalytic activity for peptide bond formation. The
proteins stabilize the ribosome structure.
Question 9
The rough endoplasmic reticulum is characterized by:
A) Ribosomes attached to its surface
B) No ribosomes attached to its surface
C) Synthesis of lipids
D) Storage of calcium
Answer: A
Explanation: The rough endoplasmic reticulum is characterized by
ribosomes attached to its surface. It is involved in protein synthesis and
modification. The smooth ER has no ribosomes and is involved in lipid
synthesis.
Question 10
The smooth endoplasmic reticulum is responsible for:
A) Lipid synthesis and detoxification
B) Protein synthesis
C) Ribosome assembly
D) DNA replication
Answer: A
Explanation: The smooth endoplasmic reticulum is responsible for lipid
synthesis, detoxification, and calcium storage. It has no ribosomes on its
surface. The rough ER is involved in protein synthesis.
With 2026 High Yield Questions and Detailed
Rationales for Medical and Graduate Students
Exam Overview
This comprehensive practice examination contains 300 questions
covering cell and molecular biology. The content is divided into five
major sections: Cell Structure and Organelles, Cell Membrane and
Transport, Cell Signaling and Communication, Cell Cycle and Division,
and Molecular Genetics and Gene Expression. Each question is
followed by a detailed rationale explaining the correct answer and why
the distractors are incorrect. This exam is designed to prepare students
for cell and molecular biology coursework and advanced studies.
Section One: Cell Structure and Organelles Questions 1 through 60
Question 1
The cell is the basic structural and functional unit of:
A) All living organisms
B) All prokaryotic organisms
C) All eukaryotic organisms
D) All multicellular organisms
Answer: A
Explanation: The cell is the basic structural and functional unit of all living
organisms. Cells are the smallest unit of life that can perform all life
processes. Prokaryotic and eukaryotic organisms are both composed of
cells.
Question 2
Prokaryotic cells are characterized by:
A) Absence of a true nucleus and membrane-bound organelles
B) Presence of a true nucleus and membrane-bound organelles
,
C) Presence of a cell wall composed of chitin
D) Presence of mitochondria and chloroplasts
Answer: A
Explanation: Prokaryotic cells are characterized by the absence of a true
nucleus and membrane-bound organelles. Their genetic material is not
enclosed within a nuclear membrane. Bacteria and archaea are prokaryotic
organisms.
Question 3
Eukaryotic cells are characterized by:
A) Presence of a true nucleus and membrane-bound organelles
B) Absence of a true nucleus and membrane-bound organelles
C) Presence of a cell wall composed of peptidoglycan
D) Absence of mitochondria and chloroplasts
Answer: A
Explanation: Eukaryotic cells are characterized by the presence of a true
nucleus and membrane-bound organelles. Their genetic material is enclosed
within a nuclear membrane. Animals, plants, fungi, and protists are
eukaryotic organisms.
Question 4
The nucleus contains which structures?
A) Chromatin, nucleolus, and nuclear envelope
B) Ribosomes, mitochondria, and endoplasmic reticulum
C) Golgi apparatus and lysosomes
D) Vacuoles and peroxisomes
Answer: A
Explanation: The nucleus contains chromatin, which is DNA and proteins,
the nucleolus, which is involved in ribosome assembly, and the nuclear
envelope, which surrounds the nucleus. Ribosomes and mitochondria are
not in the nucleus.
Question 5
,
The nucleolus is responsible for:
A) Ribosome assembly
B) Protein synthesis
C) DNA replication
D) Cell division
Answer: A
Explanation: The nucleolus is responsible for ribosome assembly. It
contains ribosomal RNA and proteins. Ribosomes are then transported to
the cytoplasm for protein synthesis.
Question 6
The nuclear envelope is composed of:
A) Two lipid bilayers with nuclear pores
B) A single lipid bilayer with nuclear pores
C) Two lipid bilayers without nuclear pores
D) A single lipid bilayer without nuclear pores
Answer: A
Explanation: The nuclear envelope is composed of two lipid bilayers with
nuclear pores. The nuclear pores allow the transport of molecules between
the nucleus and the cytoplasm. The outer membrane is continuous with the
endoplasmic reticulum.
Question 7
Ribosomes are responsible for:
A) Protein synthesis
B) Lipid synthesis
C) Carbohydrate synthesis
D) Nucleic acid synthesis
Answer: A
Explanation: Ribosomes are responsible for protein synthesis. They translate
messenger RNA into polypeptide chains. Ribosomes are composed of
ribosomal RNA and proteins.
,
Question 8
Ribosomes are composed of:
A) rRNA and proteins
B) DNA and proteins
C) mRNA and proteins
D) tRNA and proteins
Answer: A
Explanation: Ribosomes are composed of ribosomal RNA and proteins. The
rRNA provides the catalytic activity for peptide bond formation. The
proteins stabilize the ribosome structure.
Question 9
The rough endoplasmic reticulum is characterized by:
A) Ribosomes attached to its surface
B) No ribosomes attached to its surface
C) Synthesis of lipids
D) Storage of calcium
Answer: A
Explanation: The rough endoplasmic reticulum is characterized by
ribosomes attached to its surface. It is involved in protein synthesis and
modification. The smooth ER has no ribosomes and is involved in lipid
synthesis.
Question 10
The smooth endoplasmic reticulum is responsible for:
A) Lipid synthesis and detoxification
B) Protein synthesis
C) Ribosome assembly
D) DNA replication
Answer: A
Explanation: The smooth endoplasmic reticulum is responsible for lipid
synthesis, detoxification, and calcium storage. It has no ribosomes on its
surface. The rough ER is involved in protein synthesis.
