Understanding Oncogenes and Tumor Suppressor Genes

The video tutorial discusses tumor biology, focusing on oncogenes and tumor suppressor genes. It explains how proto-oncogenes, which normally promote cell growth, can mutate into oncogenes that cause cancer. The tutorial also covers tumor suppressor genes, which act as brakes on cell division, and how their inactivation leads to cancer. The two-hit hypothesis and the role of the p53 gene in DNA repair and apoptosis are also discussed.

What is the primary function of proto-oncogenes in healthy cells?

• To induce apoptosis

• To stimulate cell division and growth

• To inhibit cell division

• To repair DNA damage

What type of mutation transforms a proto-oncogene into an oncogene?

• Loss of function mutation

• Gain of function mutation

• Silent mutation

• Nonsense mutation

What is the result of a gain of function mutation in proto-oncogenes?

• Enhanced DNA repair

• Uncontrolled cell division

• Decreased cell proliferation

• Increased apoptosis

What is the role of tumor suppressor genes in normal cell function?

• To accelerate cell division

• To repair DNA mistakes and slow down cell division

• To promote cell growth

• To mutate into oncogenes

What analogy is used to describe the function of tumor suppressor genes?

• A gear shift in a car

• A brake pedal in a car

• A gas pedal in a car

• A steering wheel in a car

According to the two-hit hypothesis, how many alleles must be mutated for tumor suppressor genes to lose function?

• One allele

• Two alleles

• Three alleles

• Four alleles

What is the function of the p53 protein in cells?

• To repair DNA and induce apoptosis

• To act as a molecular switch

• To promote cell division

• To mutate into an oncogene

What happens when tumor suppressor genes are inactivated?

• Apoptosis is initiated

• Cancer is promoted

• DNA repair is enhanced

• Cell division is slowed down

What percentage of human cancers involve p53 mutations?

• 25%

• 75%

• 10%

• 50%

What is the main difference between proto-oncogenes and tumor suppressor genes?

• Both inhibit cell division

• Both promote cell division

• Proto-oncogenes promote cell division, while tumor suppressor genes inhibit it

• Proto-oncogenes inhibit cell division, while tumor suppressor genes promote it