A mutation that results in a single amino acid substitution in Ras abolishes its ability to hydrolyze GTP, even when GTPase-activating proteins (GAPs) are present. Approximately 30% of human cancers have this mutation in Ras. The pharmaceutical company AztraZeneca, which markets popular breast cancer drugs like Iressa® (generic: Gefitinib) has recently developed a new drug that prevents the dimerization of a receptor tyrosine kinase expressed in lung cancer cells, which signals via Ras. Would you expect this new drug to be effective for the treatment of cancers that express the mutant form of Ras?

The new drug will not be effective against the treatment of cancer.

Explanation:

The drug will not be effective against the cancer treatment because the drug will inhibit the dimerization of receptor tyrosine kinase (RTK) but as the Ras has undergone mutation due to replacement of one amino acid, it will be constitutively expressed and the drug is not effective in stopping the Ras functioning.

Thus, Gefitinib cannot work against the cancerous cell as it is not potent to stop the functioning of mutant Ras protein.

americans began to notice growing differences between the northern and southern sections of the country. there were more people living in cities in the north, which made it more urban. more people lived on farms in the south, which made it more rural. while many people were farmers in the northern states, there were now other ways to make a living, such as working in mechanical cotton gins factories manufacturing cloth, tools and other goods. people in the north supported high tariffs on goods imported from europe because the extra cost encouraged people to “buy american” instead. in the southern states, planters did not like tariffs because they sold most of their production to europe and bought their tools from there as well. southerners believed the protective tariff was something that only northern factory owners keep their profits high. so the southern politicians came up with an idea. they would opt out. they would simply ignore the protective tariff. it was ‘null and void’ in south carolina. the state would not collect the taxes on goods imported into south carolina, no matter what the president said they had to do. this decision led to the nullification crisis.