


X Weiss, (2008) We are made up of thousands of billions of cells that must act in concert to allow us to perform our daily activities and meet challenges. This cooperation is achieved partly by cells communicating with each other. Sensory neurons have specialized receptors that convert diverse types of stimuli from the environment (e.g., light, touch, sound, odorants) into electric signals. These electric signals are then converted into chemical signals that are passed on to other cells, which convert the information back into electric signals. Chemical signals, or first messengers, transmit information between cells., while electric signals, or second messengers, process and conduct information within a cell. Cellular communication involves signals between cells -- i.e. first messengers, and signals within a cell -- i.e. second messengers. The first messenger is converted or transducted to a second messenger within a cell. Signal transduction refers to small ion movements changing the cell’s electrical potential. More complex signal transduction changes enzyme activities and protein conformations. Protein conformation is necessary for normal protein function and overall cellular intelligence, since proteins represent the brain of the cell. Any alteration in cellular activity is related to changes in the program of genes expressed within the responding cells.