All GRE Subject Test: Biology Resources
Example Questions
Example Question #63 : Genetics, Dna, And Molecular Biology
Which of the following choices could activate a proto-oncogene?
Any of these could activate a proto-oncogene
Chromosomal translocations
Exposure to mutagens
Gene duplication
Any of these could activate a proto-oncogene
Proto-oncogenes are genes that have the ability to become oncogenes (genes that cause cancer). There are many ways to activate proto-oncogenes. Gene duplication can cause an increase in the expression of a particular protein, which can lead to cancer. Exposure to mutagens can cause a mutation on a proto-oncogene, which causes it to become activated. Chromosomal translocations can relocate proto-oncogenes to areas where they are expressed more rapidly. Most proto-oncogenes are involved in cell cycle regulation. Irregular expression of these genes can allow the cell to progress through the cell cycle too rapidly, resulting in unregulated cell division and tumor formation.
Example Question #64 : Genetics, Dna, And Molecular Biology
Which of the following best describes an oncogene?
A gene that stimulates apoptosis in cells
A gene that causes uncontrollable growth
A gene that no longer makes a viable protein
A gene that regulates cell growth
A gene that causes uncontrollable growth
Oncogenes can be thought of as cancerous genes, or rather a gene that has the potential to cause cancer. They typically occur when a normal proto-oncogene undergoes a mutation. Proto-oncogenes normally code for growth and development in cells, and tightly regulate these processes. If mutated, these newly cancerous genes can stimulate unregulated growth, a symptom characteristic of cancerous cells.
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