QQ- 6

What is the typical outcome when proto-oncogenes undergo mutation?

• They become tumor suppressor genes

• They lose all function

• They continue to regulate normal cell behavior

• They may become oncogenes and promote uncontrolled cell growth

What initiates the transition from the G1 phase to the S phase in the cell cycle?

• DNA replication

• G1 cyclin expression

• Mitosis completion

• Cell differentiation

Which transcription factor is responsible for controlling transcription activation during the cell cycle?

• p53 tumor suppressor

• Cyclin D

• E2F transcription factor

• CDK inhibitor

Which medical condition results from a defect in the Rb gene?

• Cataracts

• Glaucoma

• Retinoblastoma

• Macular degeneration

When does the genetic predisposition to cancer become relevant in individuals with one functional Rb gene (Rb+)?

• It is always relevant in such individuals

• It never becomes relevant in such individuals

• The predisposition becomes relevant when a second mutation occurs in the other Rb gene, leading to tumor development

• It becomes relevant only in old age

How does the "Cancer Barrier" relate to colon tumor formation risk?

• It accelerates cellular death or suppression

• It facilitates cancer cell shedding

• It identifies obstacles to tumor formation, including cancer

• It promotes cancer cell accumulation in crypts