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).
Membrane-Embedded Proteins. Various proteins, including ion channels, protein pumps and carrier proteins, help large or charged molecules pass through a cell membrane. Ion channels allow ions, which are atoms and molecules with missing or extra electrons, to pass through a cell membrane. These proteins form a gate that opens and closes based on the voltage of the cell and the ion.