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).
Movement of substances across the plasma membrane by protein carrier molecules (integral membrane protein) --used when molecule cannot cross membrane or crosses very slowly. --protein carrier molecules are embedded in lipid, and have site which specifically binds the molecules. --binding of the molecule to the site promotes a conformational change in protein carrier, resulting in transport of molecule across membrane.