Concept explainers
Introduction:
Cellular membrane, nucleus, and cytoplasm are the three major components of a cell. Cellular membrane which surrounds the entire cell is composed of phospholipids and proteins. Peripheral proteins are generally found on the membrane surface and are temporarily attached to one face of the plasma membrane. Membrane proteins that traverse the entire cell membrane alone can serve as a membrane channel. A membrane channel aids in the transfer of solutes from one side of the cell membrane which is selectively permeable to the other side of the membrane. Such integral proteins are called as transmembrane proteins. Hormones, like epinephrine (first messenger) do not have the ability to enter the cell through the cell membrane. Thus, they activate the production of a second messenger within the cell.
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ANATOMY & PHYSIOLOGY: THE UNITY OF FORM
- The resting membrane potential of a cell is polarized, meaning that it has a _____ charge on the outside of the cell membrane and a ______ charge on the inside of the cell membranearrow_forwardSecond messengers are needed because: Most ligands cannot enter the cell so they help transmit messages to the cell interior They speed up the rate at which cells respond to signals They catalyze transcription and translation They provide energy for signal transductionarrow_forwardDescribe one type of receptorarrow_forward
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