Membrane potentials

Question 1

Voltage

Answer 1

Moving protons out of a cell to make a charged cell

Question 2

Membrane potential

Answer 2

measure of difference in charge inside and outside the cell

Question 3

Current

Answer 3

direction of net movement of positive charges

Question 4

Which direction does K+ flow and what is the resulting charge of the cell? which cells use K+ channels?

Answer 4

flows from inside to outside of the cell creating a negative charge inside the cell. Used in neurons

Question 5

Which direction does Cl- flow and what is the resulting charge of the cell? which cells use Cl- channels?

Answer 5

flows from outside to inside creating a negative charge within the cell, in skeletal muscle

Question 6

Which direction does Na+ flow and what is the resulting charge of the cell?

Answer 6

From outside to inside creating a positive charge within the cell

Question 7

Which direction does Ca2+ flow and what is the resulting charge of the cell?

Answer 7

outside to inside, creating a positive charge within the cell

Question 8

Which molecules are permeable through the plasma membrane?

Answer 8

hydrophobic: aspirin, steroid hormones, local anesthetics.

Small, neutral, non polar: O2, CO2

Question 9

Which molecules are NOT permeable through the plasma membrane?

Answer 9

Small ions, proteins, insulin, nucleic acids, polar molecules like ATP, sugars, Acetylcholine - neurotransmitter

Question 10

How does Ca2+ get unto sarcoplasm of muscle cells?

Answer 10

Ca2+ ATPase - actively transports calcium across the membrane and into the lumen using ATP

Question 11

How does the Na-K pump create a concentration/electric gradient?

Answer 11

Pumps 3 Na+ out, and 2 K+ into the cell, creating a net negative charge within the cell.