How to prepare for your annual encounter with confusion. Daylight Saving Time ends Sunday at 2 a.m., which means that weâre all going to spend a few minutes scratching our heads trying to figure out whether weâre gaining or losing an hour of sleep. Save yourself the trouble and let TIME break it down for you.
For example, plasma membrane proteins carry out functions as diverse as ferrying nutrients across the plasma membrane, receiving chemical signals from outside the cell, translating chemical signals into intracellular action, and sometimes anchoring the cell in a particular location (Figure 4).
THE DISCOVERY OF RIBOZYMES. The central role for many proteins in a cell is to catalyze chemical reactions that are essential for the cell's survival. These proteins are known as enzymes. Until relatively recently, it was thought that proteins were the only biological molecules capable of catalysis.