PCB 3023 Final Exam 08/27/2026
PCB 3023 Final Exam: (Latest Update 2026 /
2027) Molecular Cell Biology | Questions &
Answers | Grade A | 100% Correct - UCF
You create cells with a version of Cdc6 that cannot be phosphorylated and thus cannot be degraded.
What is the likely consequence of this change in Cdc6?
A. Cells will enter another S phase prematurely.
B. Cells will be unable to complete DNA synthesis.
C. The origin recognition complex (ORC) will be unable to bind to DNA.
D. Cde6 will be produced inappropriately during M phase.
A. Cells will enter another S phase prematurely.
The Retinoblastoma protein
A. is a negative regulator of proliferation.
B. is a positive regulator of proliferation.
C. drives the transition from G, to S phase.
D. blocks the transition from G, to M phase.
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, PCB 3023 Final Exam 08/27/2026
A. is a negative regulator of proliferation.
What would a cak (Cdk activating kinase) mutant look like?
A. weel-
B. cdc25-
C. wild type
B. cdc25-
Which is a regulator of M-Cdk at the M checkpoint?
А. АРС
B. Rb
C. S-Cdk
D. Securin
E. Cdc25
А. АРС
A malignant tumor is more dangerous than a benign tumor because
A. its cells are proliferating faster
B. it causes neighboring cells to mutate
C. its cells attack and phagocytose neighboring normal tissue cells
D. its cells invade other tissues
its cells invade other tissues
Which of the following statements about cancer is false?
A. Viruses cause some cancers.
B. Cancer is a disease of enhanced cell proliferation and reduced cell death.
C. A mutation in even a single cancer-critical gene is sufficient to convert a normal cell into a cancer
cell.
D. Some carcinogens cause cancer by changing the nucleotide sequence of DNA.
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, PCB 3023 Final Exam 08/27/2026
C. A mutation in even a single cancer-critical gene is sufficient to convert a normal cell into a
cancer cell.
Q3. Which of the following genetic changes would not convert a proto-oncogene into an oncogene?
A. A mutation that introduces a stop codon immediately after the codon for the initiator methionine.
B. A mutation within the coding sequence that makes the protein hyperactive.
C. An amplification of the proto-oncogene, causing overproduction of the normal protein.
D. A mutation in the promoter of the proto-oncogene, causing the normal protein to be expressed at
an abnormally high level
.
A. A mutation that introduces a stop codon immediately after the codon for the initiator
methionine.
Which of the following statements about tumor suppressor genes is false?
A. Gene amplification of a tumor suppressor gene is less dangerous than gene amplification of a proto-
oncogene.
B. Cells with one functional copy of a tumor suppressor gene will usually proliferate faster than normal
cells.
C. Homozygous inactivation of a tumor suppressor gene leads to enhanced cell survival and
proliferation.
D. Individuals with only one functional copy of a tumor suppressor gene are more prone to cancer
than individuals with two functional copies of a tumor suppressor gene.
B. Cells with one functional copy of a tumor suppressor gene will usually proliferate faster than
normal cells.
A mutation in the epidermal growth factor receptor (EGFR) causes the receptor to send a positive
signal along its intracellular signaling pathway even when the EGF ligand is not bound to it. This signal
leads to abnormal cell proliferation in the absence of growth factor. On the basis of this information,
would you classify the EGFR gene as a tumor suppressor gene or a proto-oncogene?
A. tumor suppressor
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, PCB 3023 Final Exam 08/27/2026
B. proto-oncogene
C. neither
proto-oncogene
Which of the following descriptions is consistent with the behavior of a cell that lacks a protein
required for a checkpoint mechanism that operates in G2?
A) The cell would be unable to enter M phase.
B) The cell would be unable to enter G2.
C) The cell would enter M phase under conditions when normal cells would not.
D) The cell would pass through M phase more slowly than normal cells.
C) The cell would enter M phase under conditions when normal cells would not.
Progression through the cell cycle requires a cyclin to bind to a Cdk because
A) the cyclins are the molecules with the enzymatic activity in the complex.
B) the binding of a cyclin to Cdk is required for Cdk enzymatic activity.
C) cyclin binding inhibits Cdk activity until the appropriate time in the cell cycle.
D) without cyclin binding, a cell-cycle checkpoint will be activated.
B) the binding of a cyclin to Cdk is required for Cdk enzymatic activity.
Levels of Cdk activity change during the cell cycle, in part because
A)the Cdks phosphorylate each other.
B) the Cdks activate the cyclins.
C) Cdk degradation precedes entry into the next phase of the cell cycle.
D) cyclin activity changes during the cycle.
P a g e 4 | 63
PCB 3023 Final Exam: (Latest Update 2026 /
2027) Molecular Cell Biology | Questions &
Answers | Grade A | 100% Correct - UCF
You create cells with a version of Cdc6 that cannot be phosphorylated and thus cannot be degraded.
What is the likely consequence of this change in Cdc6?
A. Cells will enter another S phase prematurely.
B. Cells will be unable to complete DNA synthesis.
C. The origin recognition complex (ORC) will be unable to bind to DNA.
D. Cde6 will be produced inappropriately during M phase.
A. Cells will enter another S phase prematurely.
The Retinoblastoma protein
A. is a negative regulator of proliferation.
B. is a positive regulator of proliferation.
C. drives the transition from G, to S phase.
D. blocks the transition from G, to M phase.
P a g e 1 | 63
, PCB 3023 Final Exam 08/27/2026
A. is a negative regulator of proliferation.
What would a cak (Cdk activating kinase) mutant look like?
A. weel-
B. cdc25-
C. wild type
B. cdc25-
Which is a regulator of M-Cdk at the M checkpoint?
А. АРС
B. Rb
C. S-Cdk
D. Securin
E. Cdc25
А. АРС
A malignant tumor is more dangerous than a benign tumor because
A. its cells are proliferating faster
B. it causes neighboring cells to mutate
C. its cells attack and phagocytose neighboring normal tissue cells
D. its cells invade other tissues
its cells invade other tissues
Which of the following statements about cancer is false?
A. Viruses cause some cancers.
B. Cancer is a disease of enhanced cell proliferation and reduced cell death.
C. A mutation in even a single cancer-critical gene is sufficient to convert a normal cell into a cancer
cell.
D. Some carcinogens cause cancer by changing the nucleotide sequence of DNA.
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, PCB 3023 Final Exam 08/27/2026
C. A mutation in even a single cancer-critical gene is sufficient to convert a normal cell into a
cancer cell.
Q3. Which of the following genetic changes would not convert a proto-oncogene into an oncogene?
A. A mutation that introduces a stop codon immediately after the codon for the initiator methionine.
B. A mutation within the coding sequence that makes the protein hyperactive.
C. An amplification of the proto-oncogene, causing overproduction of the normal protein.
D. A mutation in the promoter of the proto-oncogene, causing the normal protein to be expressed at
an abnormally high level
.
A. A mutation that introduces a stop codon immediately after the codon for the initiator
methionine.
Which of the following statements about tumor suppressor genes is false?
A. Gene amplification of a tumor suppressor gene is less dangerous than gene amplification of a proto-
oncogene.
B. Cells with one functional copy of a tumor suppressor gene will usually proliferate faster than normal
cells.
C. Homozygous inactivation of a tumor suppressor gene leads to enhanced cell survival and
proliferation.
D. Individuals with only one functional copy of a tumor suppressor gene are more prone to cancer
than individuals with two functional copies of a tumor suppressor gene.
B. Cells with one functional copy of a tumor suppressor gene will usually proliferate faster than
normal cells.
A mutation in the epidermal growth factor receptor (EGFR) causes the receptor to send a positive
signal along its intracellular signaling pathway even when the EGF ligand is not bound to it. This signal
leads to abnormal cell proliferation in the absence of growth factor. On the basis of this information,
would you classify the EGFR gene as a tumor suppressor gene or a proto-oncogene?
A. tumor suppressor
P a g e 3 | 63
, PCB 3023 Final Exam 08/27/2026
B. proto-oncogene
C. neither
proto-oncogene
Which of the following descriptions is consistent with the behavior of a cell that lacks a protein
required for a checkpoint mechanism that operates in G2?
A) The cell would be unable to enter M phase.
B) The cell would be unable to enter G2.
C) The cell would enter M phase under conditions when normal cells would not.
D) The cell would pass through M phase more slowly than normal cells.
C) The cell would enter M phase under conditions when normal cells would not.
Progression through the cell cycle requires a cyclin to bind to a Cdk because
A) the cyclins are the molecules with the enzymatic activity in the complex.
B) the binding of a cyclin to Cdk is required for Cdk enzymatic activity.
C) cyclin binding inhibits Cdk activity until the appropriate time in the cell cycle.
D) without cyclin binding, a cell-cycle checkpoint will be activated.
B) the binding of a cyclin to Cdk is required for Cdk enzymatic activity.
Levels of Cdk activity change during the cell cycle, in part because
A)the Cdks phosphorylate each other.
B) the Cdks activate the cyclins.
C) Cdk degradation precedes entry into the next phase of the cell cycle.
D) cyclin activity changes during the cycle.
P a g e 4 | 63
