Lecture 2-1 Basics of Ion Movement

Question 1

How do neural cells create electrical activity?

Answer 1

-Ions

Question 2

What are ions?

Answer 2

-Ions are charged particles essential for neuronal activity
-Key Ions: Sodium (Na+), potassium (K+), chloride (Cl-)
-The movement of these ions generates electrical impulses

Question 3

How does ion movement in the membrane work?

Answer 3

-using the phospholipid bilayer:
-Impermeable
-cannot transport ions

• using Membrane-spanning proteins:
  -Transporter, Pumps : need energy, conformational changes
  - ion channel: quick, passive pathways for ion: open-close, no need energy

Question 4

What does ion movement in the cells look like with a phospholipid membrane ONLY?

Answer 4

-Ions cannot cross the membrane

Question 5

What does ion movement look like with a phospholipid membrane with ion channels?

Answer 5

-Example with a chloride channel: only Cl- can move through this hole, then the electrical activity happens

Question 6

What are the Basic principles of ion movement?

Answer 6

-Ions are charged particles essential for neuronal activity
-Key ions: sodium (Na+), potassium (K+), chloride (Cl-)
-The movement of these ions generates electrical charges

Question 7

What does happen ion movement follows the concentration gradient?

Answer 7

-Ion movement follows the concentration gradient
-Concentration gradient: the concentration difference between two points in space
-Ions move toward
Higher concentration to Lower concentration
Until equal distribution: concentration equilibrium

Question 8

What does happen ion movement follows the electrical gradient?

Answer 8

-electric gradient: the voltage difference between two points in space

-Positive ions move toward the direction of Negative ions
-Negative ions move toward the direction of Positive ions

 -Until the charges are equally distributed: electric equilibrium

Question 9

What is a membrane potential?

Answer 9

In the neural cells, The movement of ions through ion channels generates electrical activity
: Na+, K+, Cl-

The movement of ions following
- Concentration gradient
- Electric gradient

Membrane potential
A voltage difference between the inside and outside of cells