Active Transport
Higher Tier Only
- Active transport can be defined as:
The movement of molecules across a selectively permeable membrane against a concentration gradient
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- In active transport molecules move from a region of lower concentration to a region of higher concentration
- The movement of molecules against a concentration gradient requires energy from respiration
- Respiration produces a molecule called ATP
- ATP powers the activity of specialised carrier molecules within cell membranes; these carriers act as 'pumps' to move substances against a gradient
Active transport diagram
Active transport is the movement of substances across a cell membrane against a concentration gradient
It requires energy in the form of ATP
