Week 12 - Cancer Biology Flashcards
(25 cards)
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: C) To transmit growth signals after being activated
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: C) 15-20%
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: B) Binding to GTP
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: C) It mediates growth signals by binding GTP and GDP.
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: B) To add phosphate groups to proteins
Which transcription factor is known as a “supercharger” for cell proliferation?
A) TP53
B) RAS
C) Myc
D) NF-kB
Answer: C) Myc
What genetic alteration is commonly associated with lymphoma involving the Myc gene?
A) Deletion
B) Duplication
C) Translocation
D) Inversion
Answer: C) Translocation, 8 and 14 chromosomes
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: A) A mutated form of a proto-oncogene that promotes cancer.
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: C) Inhibit progression to S-phase
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: B) Causes cell cycle arrest in response to DNA damage
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: B) G1-S checkpoint
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: C) By driving transcription of growth-promoting genes
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: B) Both alleles of a tumor suppressor gene must be inactivated.
What happens to telomeres with each cell division?
A) They lengthen
B) They shorten
C) They remain the same
D) They disappear
Answer: B) They shorten
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: B) It lengthens telomeres, allowing continued cell division
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: B) Angiogenesis
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: B) Overexpressing BCL-2
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: B) Cells lose their adhesive properties and gain migratory capabilities.
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: C) DNA mismatch repair gene mutation
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: B) By binding and inactivating RB and degrading p53
Which protein is known as the “guardian of the genome”?
A) Myc
B) RAS
C) p53
D) RB
Answer: C) p53
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
D) To signal for DNA repair
Answer: A) To ensure DNA is fully replicated and undamaged
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: A) G0 phase
What type of therapy uses monoclonal antibodies against cancer cell receptors?
A) Hormone therapy
B) Immune-based therapy
C) Radiation therapy
D) Chemotherapy
Answer: B) Immune-based therapy
