PCAT Biology Exam
Question 1. Which organelle is primarily responsible for energy
production in eukaryotic cells?
A) Golgi apparatus
B) Mitochondria
C) Lysosome
D) Endoplasmic reticulum
Answer: B
Explanation: Mitochondria are known as the powerhouses of the cell
because they generate ATP through cellular respiration, providing
energy for cellular processes.
Question 2. Which of the following structures is unique to prokaryotic
cells?
A) Nucleus
B) Mitochondria
C) Nucleoid region
D) Endoplasmic reticulum
Answer: C
Explanation: Prokaryotic cells lack a true nucleus; instead, they have a
,PCAT Biology Exam
nucleoid region where their DNA is localized, unlike eukaryotic cells that
have a membrane-bound nucleus.
Question 3. During the process of diffusion, molecules move:
A) From areas of low concentration to high concentration
B) Against their concentration gradient
C) From areas of high concentration to low concentration
D) In a directed, energy-dependent manner
Answer: C
Explanation: Diffusion is the passive movement of molecules from an
area of high concentration to an area of low concentration, driven by
the concentration gradient.
Question 4. Which phase of the cell cycle is characterized by the
duplication of the genetic material?
A) G1 phase
B) S phase
C) G2 phase
D) M phase
Answer: B
,PCAT Biology Exam
Explanation: The S phase (synthesis phase) involves DNA replication,
ensuring each daughter cell receives an identical copy of the genome
during cell division.
Question 5. Apoptosis is best described as:
A) Cell division
B) Programmed cell death
C) Cell differentiation
D) Cellular aging
Answer: B
Explanation: Apoptosis is a controlled, programmed process of cell
death that is essential for development and removal of damaged cells.
Question 6. Enzymes are catalysts that:
A) Are consumed in reactions
B) Increase activation energy
C) Lower activation energy and increase reaction rate
D) Are only active at high temperatures
Answer: C
Explanation: Enzymes lower the activation energy required for
, PCAT Biology Exam
reactions, thereby increasing the rate without being consumed in the
process.
Question 7. Which process occurs in the mitochondria during cellular
respiration?
A) Glycolysis
B) Calvin cycle
C) Krebs cycle
D) Photosynthesis
Answer: C
Explanation: The Krebs cycle (citric acid cycle) occurs in the
mitochondria, generating electron carriers used in oxidative
phosphorylation to produce ATP.
Question 8. Photosynthesis involves which of the following as a product
of the light-dependent reactions?
A) Glucose
B) Oxygen
C) NADPH
D) ATP
Question 1. Which organelle is primarily responsible for energy
production in eukaryotic cells?
A) Golgi apparatus
B) Mitochondria
C) Lysosome
D) Endoplasmic reticulum
Answer: B
Explanation: Mitochondria are known as the powerhouses of the cell
because they generate ATP through cellular respiration, providing
energy for cellular processes.
Question 2. Which of the following structures is unique to prokaryotic
cells?
A) Nucleus
B) Mitochondria
C) Nucleoid region
D) Endoplasmic reticulum
Answer: C
Explanation: Prokaryotic cells lack a true nucleus; instead, they have a
,PCAT Biology Exam
nucleoid region where their DNA is localized, unlike eukaryotic cells that
have a membrane-bound nucleus.
Question 3. During the process of diffusion, molecules move:
A) From areas of low concentration to high concentration
B) Against their concentration gradient
C) From areas of high concentration to low concentration
D) In a directed, energy-dependent manner
Answer: C
Explanation: Diffusion is the passive movement of molecules from an
area of high concentration to an area of low concentration, driven by
the concentration gradient.
Question 4. Which phase of the cell cycle is characterized by the
duplication of the genetic material?
A) G1 phase
B) S phase
C) G2 phase
D) M phase
Answer: B
,PCAT Biology Exam
Explanation: The S phase (synthesis phase) involves DNA replication,
ensuring each daughter cell receives an identical copy of the genome
during cell division.
Question 5. Apoptosis is best described as:
A) Cell division
B) Programmed cell death
C) Cell differentiation
D) Cellular aging
Answer: B
Explanation: Apoptosis is a controlled, programmed process of cell
death that is essential for development and removal of damaged cells.
Question 6. Enzymes are catalysts that:
A) Are consumed in reactions
B) Increase activation energy
C) Lower activation energy and increase reaction rate
D) Are only active at high temperatures
Answer: C
Explanation: Enzymes lower the activation energy required for
, PCAT Biology Exam
reactions, thereby increasing the rate without being consumed in the
process.
Question 7. Which process occurs in the mitochondria during cellular
respiration?
A) Glycolysis
B) Calvin cycle
C) Krebs cycle
D) Photosynthesis
Answer: C
Explanation: The Krebs cycle (citric acid cycle) occurs in the
mitochondria, generating electron carriers used in oxidative
phosphorylation to produce ATP.
Question 8. Photosynthesis involves which of the following as a product
of the light-dependent reactions?
A) Glucose
B) Oxygen
C) NADPH
D) ATP
