Why is the resting membrane potential negative? Shouldn't it be positive as cells move in and out positive ions

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

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 is a common feature of the voltage sensitive Ca++, Na+ and K+ ion channels? A single polypeptide sequence made up of 4 domains A voltage sensing S4 transmembrane domain A transmembrane S5-S6 hydrophobic subunit that binds the membrane A voltage sensing extracellular P loop

Which of the following statements about ion channels are true? all ion channels are selective for only one species of ion The only way ions can cross the membrane is through the actions of a transporter. ions can flow though the pores of ion channels faster than they can diffuse freely in solution the movement of ions through the pore of an ion channel does not require energy

Describe two things that contribute to the resting membrane potential

A change in membrane potential which is due to ion influx or efflux in a single region with the ions then diffusing away from that region is called a(n) ______

Which one of the following will have the most difficulty in crossing the plasma membrane?     Na+ ions     oxygen     "small, nonpolar, hydrophobic molecules such as fatty acids"     carbon dioxide

Ions like K+ cannot diffuse directly across the membrane. They need open ion channels to cross the membrane. Explain why.

Which of the following statements is false? ○ Voltage, stretch, and temperature are all factors that regulate the opening of ions channels The whole cell current (macroscopic current) can be calculated by summing the many microscopic single channel currents It is not possible to predict the precise moment that a channel will be open or closed, only the probability that opening or closing will occur Changing the concentration gradient of an ion will cause an ion channel to open