Liberty BIOL 101 Individual Assignment 3 Answers Complete Solutions

Individual Assignment 3 – 10 Discoveries in the War on Cancer

Virologists are modifying lentiviruses as vectors for carrying proto-oncogenes into cancer-transformed cells in culture. They are developing this virus for inserting the ras proto-oncogene directly into its correct location in the genome. The correct ras gene will already be linked to human DNA on either side of it and complexed with a recombination enzyme that will insert it into its correct location within the human genome. At the same time, the recombination enzyme will excise the defective oncogenic form of ras. The cells in culture should again come under normal hormonal control and require extra-cellular signals in order to continue dividing.

Malignant brain tumors in adults are fast-growing cancers with median survival rates of 15 months, even with aggressive treatment. Researchers have been searching for genetic “signatures” (characteristic groups of cancer-causing genes) that could help in defining the kind of brain tumor the patient has. They hope to be better able to predict the course of the disease and more accurately design the patient’s course of treatment.
Tobacco smoking is the leading cause of preventable deaths worldwide. It is a risk factor for lung cancer and several other types of cancer. Results of analysis of the entire human gene collection (the “genome”) support some previous findings that a region of human chromosome number 15 contains one or more genes that are associated with smoking intensity (the number of cigarettes smoked per day) and the closely related trait of nicotine dependency. Scanning people’s genomes for these genes will help them to determine their risk of addiction should they begin smoking tobacco.
Immunologists are working with a mutation (HER2) that is expressed on the surface of many breast, bladder, pancreatic, and ovarian cancer cells. They have made antibodies against this mutant surface protein. These antibodies have been covalently bonded to a “gene expression vector” that makes cells light up when incubated with luciferin from fire flies. The vector takes the gene for luciferin into the cancer cells. The researchers have shown that their antibody can accurately find and “light up” cancer cells. Their next step is to bond the antibody to an expression vector that carries the normal HER2 gene into mutant cancer cells.
Immunologists are investigating ways to destroy lymphocytes (white blood cells of the immune system) that have become cancerous (lymphomas). A current drug Rituximab contains antibodies that bind to the surfaces of these lymphocytes setting them up for destruction by the cancer patient’s own immune system. They are currently seeking ways to modify the antibody’s structure so that it will attract the cancer patient’s “natural killer” (NK) cells to the lymphocytes. Success of this project will bring a multi-faceted immune response against lymphomas and hasten destruction.
Biochemists have discovered a protein kinase enzyme named BRAF that is an important link in a molecular pathway that causes a cell to divide. Normally, BRAF responds to signals coming from outside the cell—signals calling for the cell to divide normally under normal conditions. But there is a mutation in BRAF enzymes that causes it activate the cell toward division continually.