Active Transport (ATP Required)
Low → High Concentration (Against Gradient)
Extracellular:
8
Intracellular:
24
ATP Pool:
5
Extracellular Fluid (Outside Cell)
[Solute]: Low
[Solute]: High
Cytoplasm / Intracellular (Inside Cell)
ATP hydrolyzed to ADP + Pi! Protein conformation changed.
Hydrophilic Head
Hydrophobic Tails
Carrier / Channel Protein
Glucose Molecule
Experiment Controls
Cellular Energy (ATP)
1 ATP = 1 Pump Cycle
Carrier proteins require ATP hydrolysis (ATP → ADP + Pᵢ) to change shape and pump molecules against their concentration gradient.
2. Adjust Concentration Gradient
Extracellular (Outside)
8 molecules
Intracellular (Inside)
24 molecules
Active Transport: Glucose & Amino Acids
Cells often need to absorb nutrients like glucose or amino acids even when their concentration is already higher inside the cytoplasm than outside. Because this moves molecules against their concentration gradient, passive diffusion cannot work.
Mechanism Summary:
- Solute binds to a specific transmembrane carrier protein.
- ATP binds & hydrolyzes into ADP + Pᵢ, releasing energy.
- Protein undergoes a conformational shape change, releasing the solute inside the cell.