Cell Biology – Test 4 – Final – Cancer
1. Gene expression in Cancerous cells
a. Mutation – sequence change in the bases of DNA
b. In cancerous cells, mutations cause cells to lose control over mitosis i. Proto-oncogene – protein normally causes cells to divide, mutation causes protein to produce a higher rate of mitosis ii. Multiple changes can occur.
1. make the proto-oncogene to the oncogene (mutated version) 2. Could make copies of the same gene
3. Could cause chromosome rearrangement.
iii. Tumor suppressor gene – protein normally inhibits cell division 4. If it becomes mutated, you produce a non-functional protein or quit producing it all together 5. Can lead to excessive cell survival.
iv. The oncogene sends constant divide signals and the tumor suppressor genes are not stopping division, so the buildup of these cells can cause a tumor c. Two types of tumors
v. Benign – mass of essentially normal cells which stays at the site of origin 6. Could have almost a “tissue covering”
7. Typically don’t cause problems unless they get large vi. Malignant – mass of “cancerous” cells that displaces normal tissue growth 8. Has the ability to move and change location
2. Number of mutations
d. Most cancers require more than one mutation to occur vii. If division occurs faster, the cell doesn’t have the same amount of time to make sure everything is okay viii. Most cancers appear la...