A cell has a membrane potential of -100 mV (more negative inside than outside) and has 1,000 times more calcium ions outside the cell than inside. Which best describes a mechanism by which Ca2+ enters this cell? facilitated diffusion of Ca2+ into the cell down its electrochemical gradient movement of Ca2+ into the cell through an ion channel down its concentration gradient passive diffusion of Ca2+ into the cell down its electrochemical gradient cotransport of Ca2+ into the cell with Cl- movement of Ca2+ into the cell through a carrier protein down its electrical gradient I know that the answer is 1 but please explain why. Thank you.

Hi, please help me know if I answered this question correctly? Thanks!

Which of the following describe active transport or is an example of act transport of a substance across a membrane? Choose all correct answer Glucose transport into intestinal epithelial cells Glucose transport into muscle cells Na* ion pumping out and K* ion pumping into the cell Transport requires a mediator Requires input of energy for transport Movement of ligand against the concentration gradient

The electrochemical gradient across the plasma membraneGroup of answer choices is caused by more sodium on the inside of the cell relative to the outside of the cell Contains stored potential energy that can be harvested by the cell is caused solely by the sodium/potassium ATPase is a form of kinetic energy that can be harvested by the cell All of the above

Which of the following statements are correct? Explain your answers. The plasma membrane is highly impermeable to all charged molecules. Channels have specific binding pockets for the solute molecules they allow to pass. Transporters allow solutes to cross a membrane at much faster rates than do channels. Certain H+ pumps are fueled by light energy. The plasma membrane of many animal cells contains open K+ channels, yet the K+ concentration in the cytosol is much higher than outside the cell. A symport would function as an antiport if its orientation in the membrane were reversed (i.e., if the portion of the molecule normally exposed to the cytosol faced the outside of the cell instead). The membrane potential of an axon temporarily becomes more negative when an action potential excites it.

Cells normally exists in a steady state where the intracellular ions are constant.how is this steady state achieved by limiting the effect of extracellular ions on ions in the cell?

Which of the following can be correctly applied to gap junctions? Select all that apply Allows small molecules and ions to travel between cells They are membrane channels that allow communication between neighboring cells O Prevents cells from separating from one another O They behave as gated ion channels

Compare and contrast the different transport mechanisms: Electrochemical gradient Carrier-Mediated/Not Metabolic Energy Na+ Gradient Inhibition of Na-K Pump

How is the cell membrane like a battery? Membrane potential (think of the properties of a battery) Resting membrane potential Na+ and K+ ions -> -70 mV Na+/K+ pump Stored energy for work

what would the membrane potential be if the membrane became 10X more permeable to both sodium and chloride