Early in his presidency, Theodore Roosevelt sparked a scandal when he invited the African-American educator Booker T. Washington to dine with him and his family; he was the first president ever to entertain a black man in the White House. In 1886, Roosevelt ran unsuccessfully for mayor of New York City. Two years later, President Benjamin Harrison rewarded Rooseveltâs service to the Republican Party with a job on the U.S. Civil Service Commission; he was reappointed by Harrisonâs successor, Grover Cleveland.
1 Signaling involves a receptor, the transduction of information from the cell surface to inside the cell, and subcellular systems that make a response. 2  Receptors are proteins with specific binding sites for signaling molecules called ligands. All cells are equipped with elaborate systems for receiving signals from their environment. 2  The mechanisms involved in cell signaling are particularly crucial for understanding multi-cellular organisms, and are an important in many diseases.
1 An example of a hormone mediated cell signalling pathway is in the use of Insulin to lower blood glucose levels.2  In response to high glucose levels, Beta-Cells in the pancreas release the hormone Insulin in to the blood, which binds to cells such as muscle and liver cells. The signalling molecule binds to the Repeptor because its shape is complementary. 2  This then instigates a chain of reaction withing the cell, leading to a response. 3  Cell Signalling Pathways can be categorised based the distance over which the signalling occurs.