ATP and Active Transport

Open Ended

Do Now: What is the difference between passive and active transport?

Introduction to Active Transport and Pumps

• Active transport: Requires energy (ATP) to move molecules against their concentration gradient.

Sodium-Potassium Pump: A key example of active transport, powered by ATP, used to maintain cellular balance and resting membrane potential.

Multiple Choice

What molecule provides the energy for the sodium-potassium pump to function?

• Glucose

• Oxygen

• ATP

• Carbon dioxide

Sodium-Potassium Pump Function

• Moves Ions Against Concentration Gradient:

  • Pumps 3 sodium ions (Na⁺) out of the cell.

  • Pumps 2 potassium ions (K⁺) into the cell.

• Steps of the Pump’s Action:

  • Sodium binding: Three Na⁺ ions bind to the pump inside the cell.

  • Phosphorylation: ATP donates a phosphate group, changing the pump’s shape.

  • Sodium release: Sodium is released outside the cell.

  • Potassium binding: Two K⁺ ions bind to the pump outside the cell.

  • Phosphate release: The pump changes shape again, releasing K⁺ into the cell.

  • Cycle repeats: The pump is ready to bind more Na⁺ ions.

Multiple Choice

How does the sodium-potassium pump help maintain the cell’s resting membrane potential?

• By moving ions down their concentration gradient

• By maintaining a difference in ion concentrations between the inside and outside of the cell

• By moving water in and out of the cell

• By creating energy for the cell

Multiple Choice

How many sodium ions are moved out of the cell with each cycle of the pump?

• Two

• Three

• Four

• One

Multiple Choice

What happens to the pump when ATP phosphorylates it?

• The pump changes shape

• The pump releases water

• The pump moves faster

• The pump stops working

Multiple Choice

How many potassium ions are pumped into the cell?

• Three

• Two

• One

• Four

Multiple Choice

Why is the movement of sodium and potassium considered active transport?

• It moves ions down their concentration gradient

• It requires energy to move ions against their concentration gradient

• It uses passive diffusion

• It does not require any energy

Concentration Gradients and Active Transport

• Sodium: High concentration outside the cell.

• Potassium: High concentration inside the cell.

• The pump moves ions from low to high concentration, which requires ATP energy.

Multiple Choice

What is a concentration gradient, and how does the sodium-potassium pump work against it?

• A concentration gradient is the movement of ions from low to high concentration, which the pump supports

• A concentration gradient is the difference in solute concentration across a membrane; the pump moves ions from low to high concentration

• A concentration gradient is the movement of ions through diffusion, and the pump assists with this

• The pump only works when there is no concentration gradient

Importance of the Sodium-Potassium Pump (4:24 - 6:36)

• Electrochemical Gradient: Creates a difference in ion concentration and charge across the membrane.

• This gradient is crucial for:

  • Maintaining resting membrane potential.

  • Facilitating other transport processes, like glucose uptake.

Multiple Choice

How does the sodium-potassium pump contribute to the cell’s more negative interior charge?

• By bringing in more positive sodium ions

• By allowing ions to passively move out

• By moving three positive sodium ions out for every two positive potassium ions brought in

• By increasing the flow of potassium out of the cell

Multiple Choice

What is the role of potassium leakage channels in maintaining membrane potential?

• They let sodium leak into the cell

• They block potassium from moving

• They allow potassium ions to move out of the cell, contributing to the negative charge inside

• They pump potassium into the cell

Multiple Choice

Besides sodium and potassium, what other ions contribute to maintaining the electrochemical gradient?

• Glucose and water

• Chloride and calcium

• Hydrogen and carbon dioxide

• Oxygen and nitrogen

Match

Exit Ticket:

Match the Following

• Movement of molecules from low to high concentration

• Moves 3 sodium ions out of the cell and 2 potassium ions in

• A molecule that provides energy for cellular pumps

• The process of adding a phosphate group to change protein shape

• The difference in charge and ion concentration across a membrane

Active Transport

Sodium-Potassium Pump

ATP

Phosphorylation

Resting Membrane Potential

• Active Transport

• Sodium-Potassium Pump

• ATP

• Phosphorylation

• Resting Membrane Potential