2.7 Active Transport
Notes
Active transport uses energy (ATP) to move substances from low concentration to high concentration, against the gradient.
- Protein pumps do this, such as the sodium-potassium pump in nerve cells.
- Endocytosis: the cell takes in large particles by wrapping membrane around them. Phagocytosis is "cell eating."
- Exocytosis: vesicles fuse with the membrane to release materials out of the cell.
- Endocytosis and exocytosis also require energy.
Practice
Root cells take in minerals from soil even though the minerals are already more concentrated inside the root. This requires:
Moving from low to high concentration needs energy.
A white blood cell surrounds and engulfs a bacterium. This process is:
The membrane wraps around the bacterium to bring it inside.
A scientist adds a poison that stops ATP production. Which process would stop first?
Only active transport depends directly on ATP.
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