# Describe how osmosis and active transport differ as methods of moving substances across a cell membrane. Include in your answer what is meant by osmosis, what is meant by active transport, and how the two processes differ.

> Eduqas A-Level Biology — 1.3 Cell membranes and transport · Describe · 5 marks

## Mark scheme (5 marks)

1. Osmosis is the movement of water molecules
2. Osmosis occurs from a region of higher water concentration to a region of lower water concentration (down a concentration gradient)
3. Osmosis does not require energy (passive process)
4. Active transport moves substances against a concentration gradient (from lower to higher concentration)
5. Active transport requires energy (from respiration) whereas osmosis does not

## Key terms

- [osmosis](https://www.gradenine.co.uk/glossary/osmosis)
- [active transport](https://www.gradenine.co.uk/glossary/active-transport)
- [cell membrane](https://www.gradenine.co.uk/glossary/cell-membrane)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-osmosis-and-active-transport-15d9664c) · Published by Druglandscape Ltd.