In contrast, the electrical gradient revolves around an ion’s electrical charge and the overall charges of the intracellular and extracellular environments. The chemical gradient relies on differences in the abundance of a substance on the outside versus the inside of a cell and flows from areas of high to low ion concentration. However, energy can also be stored in the electrochemical gradient of an ion across the plasma membrane, which is determined by two factors: its chemical and electrical gradients. Generating energy for processes like glucose transport and providing a means for specialized cells such as cardiac, muscle and neurons to generate electrical impulses.Īdenosine triphosphate, or ATP, is considered the primary energy source in cells. The prevalence of positively charged sodium ions outside of the cell and the abundance of negative charged proteins inside are two major factors that contribute to the overall difference in charge across the membrane.Īctive transport uses energy to maintain the electrochemical gradient across the cell membrane with specialized membrane proteins moving ions against their electrochemical gradients. Under specific conditions however, the ions are allowed to move with their gradients. The separation of ions and molecules with positive and negative charges also means that there is an electrical gradient present. However, ion concentration is not the only factor creating a gradient across the cell membrane. So its chemical gradient is in opposition to sodium's gradient. Conversely, there is a lower concentration of potassium outside of the cell and more potassium inside. This creates a chemical or concentration gradient where sodium would flow across the cell membrane from outside to inside if it were given a path. Under normal conditions there is generally more sodium on the outside of a cell than inside. Ions that are critical for cell function including sodium and potassium are unable to diffuse across the membrane relying instead on movement by channels and transporters. One feature of this division of resources inside and outside of the cell is the maintenance of an electrochemical gradient. Keeping some molecules and ions trapped within a cell while keeping others out. I'm really frustrated with this class.The cell membrane functions as a barrier. chemical force is in, so electrical is out meaning X+ favors a more positive membrane potential at equilibrium Positive membrane potential b/c electrical force is always equal and opposite of chemical force. Yes, it will flow from intracellular to extracellular.Ĥ) What reasoning led you to your determination of which direction the ion would flow?Ī) Both the chemical and electrical gradients favor movement out.ī) Both the chemical and electrical gradients favor movement in.Ĭ) The chemical and electrical gradients balance each other out.īoth the chemical and electrical gradients favor movement out.ĥ) Based on the concentration gradient, would you predict that the equilibrium potential for X+ is a positive or negative value? (Consider: you need an electrical force to counteract the chemical force.) Through the ion channel? If so, what direction will the net electrochemical gradient(s) for X+ favor it flowing? (Assume the two gradients are of equal magnitude.)Ī) Yes, it will flow from extracellular to intracellular.ī) Yes, it will flow from intracellular to extracellular. I'm not completely sure because neither a membrane potential nor an equilibrium potential is given for the cell and ion.Ģ) Does a concentration gradient exist for X+? If it exists, what direction is the concentration gradient?ģ) Imagine an ion channel opens that allows X+ to flow. Yes, outward because opposite charges attract each other. ![]() The intracellular space is high and in the extracellular space is low.ġ) Does an electrical gradient exist for X+? If it exists, what direction is the electrical gradient? ![]() ![]() In this cell, the concentration of ion X+ in I tend to over-think and get simple questions wrong.Ī hypothetical cell membrane is positively charged on the intracellular side and negatively charged on the extracellular side.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |