Lecture Notes: Sodium Potassium Pump and Resting Membrane Potential

Introduction to Fish and Pumps

Interest in Fish: Fish enthusiasts often have aquariums of various sizes (5, 10, 20, 55 gallons)
Importance of Pumps:
- Essential for aeration and filtration
- Typically require electrical power to operate

Microscopic Pumps:
- Present in cells, do not use electrical outlets
- Require energy, often in the form of ATP

Animal Cell Structure:
- Extracellular (outside cell) and intracellular (inside cell) regions
Key Ions:
- Sodium (Na+)
- Potassium (K+)
Ion Movement Through Membrane:
- Requires proteins (channels or pumps)
Electric Potential:
- Difference in voltage inside vs. outside the cell
- Most cells are more negative inside

Process:
- Begins open to intracellular side
  - Binds 3 sodium ions
  - Gets phosphorylated (ATP transfers phosphate)
  - Changes shape, opens to extracellular side
  - Releases sodium outside
- Opens to extracellular side
  - Binds 2 potassium ions
  - Phosphate released, reverts to original position
  - Releases potassium inside
Active Transport:
- Sodium and potassium move against their concentration gradients
- Moves ions from low to high concentration

Results of Pump Activity:
- More potassium inside, more sodium outside
- Creates an electrochemical gradient
- Encourages movement from high to low concentration

Potassium Leakage Channels:
- More common, making the membrane more permeable to potassium
- Positive potassium ions moving out contribute to negative charge inside

Other Contributing Ions: Other ions also affect resting potential
Role in Cellular Processes:
- Important for action potentials
- Needed for other proteins to transport molecules like glucose

Summary:
- Sodium potassium pump is crucial for maintaining resting potential
- It establishes essential electrochemical gradients for cellular activities
Final Note: Encouragement to remain curious about cellular functions and biological processes.