Week 12 - Cancer Biology

Question 1

What is the primary function of the RAS protein in cell signaling?

A) To initiate apoptosis
B) To act as a transcription factor
C) To transmit growth signals after being activated
D) To bind to DNA directly

Answer 1

Answer: C) To transmit growth signals after being activated

Question 2

What percentage of all human tumors are associated with mutations in the RAS gene?

A) 5-10%
B) 10-15%
C) 15-20%
D) 20-25%

Answer 2

Answer: C) 15-20%

Question 3

What causes RAS to switch from its inactive to active form?

A) Binding to GDP
B) Binding to GTP
C) Binding to a kinase
D) Hydrolysis of ATP

Answer 3

Answer: B) Binding to GTP

Question 4

What is the role of the RAS protein in cell signaling?

A) It inhibits cell growth.
B) It activates the transcription of DNA.
C) It mediates growth signals by binding GTP and GDP.
D) It serves as a structural component of the cell membrane.

Answer 4

Answer: C) It mediates growth signals by binding GTP and GDP.

Question 5

What is the role of kinases in the phosphorylation cascade?

A) To remove phosphate groups from proteins
B) To add phosphate groups to proteins
C) To degrade proteins
D) To activate GTP

Answer 5

Answer: B) To add phosphate groups to proteins

Question 6

Which transcription factor is known as a “supercharger” for cell proliferation?

A) TP53
B) RAS
C) Myc
D) NF-kB

Answer 6

Answer: C) Myc

Question 7

What genetic alteration is commonly associated with lymphoma involving the Myc gene?

A) Deletion
B) Duplication
C) Translocation
D) Inversion

Answer 7

Answer: C) Translocation, 8 and 14 chromosomes

Question 8

What does the term “oncogene” refer to?
A) A mutated form of a proto-oncogene that promotes cancer.
B) A normal gene that inhibits tumor growth.
C) A gene involved in DNA repair.
D) A virus that causes cancer.

Answer 8

Answer: A) A mutated form of a proto-oncogene that promotes cancer.

Question 9

What is the primary function of the retinoblastoma (RB) protein in the cell cycle?

A) Promote DNA synthesis
B) Regulate apoptosis
C) Inhibit progression to S-phase
D) Activate cyclins

Answer 9

Answer: C) Inhibit progression to S-phase

Question 10

What is the role of p53 in the cell cycle?

A) Induces DNA replication
B) Causes cell cycle arrest in response to DNA damage
C) Promotes cell division
D) Facilitates angiogenesis

Answer 10

Answer: B) Causes cell cycle arrest in response to DNA damage

Question 11

Which checkpoint is primarily responsible for detecting DNA damage before the S phase?

A) G1-M checkpoint
B) G1-S checkpoint
C) G2-M checkpoint
D) S-G checkpoint

Answer 11

Answer: B) G1-S checkpoint

Question 12

How does Myc promote cancer?

A) By enhancing apoptosis
B) By repressing cell growth
C) By driving transcription of growth-promoting genes
D) By repairing DNA

Answer 12

Answer: C) By driving transcription of growth-promoting genes

Question 13

What is the significance of the two-hit hypothesis in cancer?

A) It applies only to oncogenes.
B) Both alleles of a tumor suppressor gene must be inactivated.
C) It explains mutations in RAS.
D) It involves chromosomal rearrangements.

Answer 13

Answer: B) Both alleles of a tumor suppressor gene must be inactivated.

Question 14

What happens to telomeres with each cell division?

A) They lengthen
B) They shorten
C) They remain the same
D) They disappear

Answer 14

Answer: B) They shorten

Question 15

What role does telomerase play in cancer cells?

A) It repairs DNA breaks.
B) It lengthens telomeres, allowing continued cell division.
C) It induces apoptosis.
D) It activates p53.

Answer 15

Answer: B) It lengthens telomeres, allowing continued cell division

Question 16

Which of the following is a hallmark of cancer associated with tumor blood supply?

A) Evasion of apoptosis
B) Angiogenesis
C) Self-sufficiency in growth signals
D) Insensitivity to growth inhibition

Answer 16

Answer: B) Angiogenesis

Question 17

What is a common method by which cancer cells evade apoptosis?

A) Upregulating p53
B) Overexpressing BCL-2
C) Inducing cell cycle arrest
D) Activating RB

Answer 17

Answer: B) Overexpressing BCL-2

Question 18

Which of the following best describes the epithelial to mesenchymal transition (EMT) in cancer?

A) Cells become more differentiated.
B) Cells lose their adhesive properties and gain migratory capabilities.
C) Cells enter senescence.
D) Cells undergo apoptosis.

Answer 18

Answer: B) Cells lose their adhesive properties and gain migratory capabilities.

Question 19

What mutation is commonly associated with hereditary nonpolyposis colorectal cancer (HNPCC)?

A) APC gene mutation
B) BRCA1 mutation
C) DNA mismatch repair gene mutation
D) RAS mutation

Answer 19

Answer: C) DNA mismatch repair gene mutation

Question 20

How does HPV contribute to cervical cancer?
A) By activating p53
B) By binding and inactivating RB and degrading p53
C) By promoting angiogenesis
D) By enhancing apoptosis

Answer 20

Answer: B) By binding and inactivating RB and degrading p53

Question 21

Which protein is known as the “guardian of the genome”?

A) Myc
B) RAS
C) p53
D) RB

Answer 21

Answer: C) p53

Question 22

What is the main purpose of the G2-M checkpoint?

A) To ensure DNA is fully replicated and undamaged
B) To initiate apoptosis
C) To promote cell differentiation

Answer 22

D) To signal for DNA repair
Answer: A) To ensure DNA is fully replicated and undamaged

Question 23

In which phase do cells typically enter senescence due to short telomeres?

A) G0 phase
B) G1 phase
C) S phase
D) G2 phase

Answer 23

Answer: A) G0 phase

Question 24

What type of therapy uses monoclonal antibodies against cancer cell receptors?

A) Hormone therapy
B) Immune-based therapy
C) Radiation therapy
D) Chemotherapy

Answer 24

Answer: B) Immune-based therapy

Question 25

What is the role of telomerase in cell replication?

Answer 25

The enzyme telomerase keeps restoring the ends of telomeres in cell replication
Telomerase is expressed in gametes and stem cells, but most tissues do NOT have telomerase

85% of cancer cells have telomerase