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Osmosis: GCSE Biology Definition

Cara Head

Written by: Cara Head

Reviewed by: Naomi Holyoak

Published

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2 minutes

Contents

  1. 1. What is osmosis?
  2. 2. Osmosis revision resources to ace your exams

What is osmosis?

In GCSE biology osmosis is the movement of water from a region of high water concentration to a region of low water concentration, across a partially permeable membrane.

A solution with a high water concentration can also be described as dilute or having a high water potential, while a solution with a low water concentration can be said to have a high solute concentration or a low water potential. The solute concentration of a solution increases when solutes, such as sugars or salt, are dissolved in water. 

Osmosis can only occur across a partially permeable membrane because the membrane prevents the movement of solute particles but allows water molecules to cross.

Diagram showing osmosis: water molecules move through a partially permeable membrane from a water solution to a cell containing sucrose molecules.
Osmosis is the movement of water molecules from a dilute solution to a concentrated solution, though a partially permeable membrane

Osmosis revision resources to ace your exams

You can find out more about osmosis in our GCSE biology revision note pages:

Meet all your GCSE biology revision needs, improve your grades, and boost your confidence using revision resources from Save My Exams. This includes revision notes, videos, flashcards and exam questions with student-friendly mark schemes.

GCSE Biology Revision Resources

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Author
Reviewer
Cara Head

Author: Cara Head

Expertise: Biology Content Creator

Cara graduated from the University of Exeter in 2005 with a degree in Biological Sciences. She has fifteen years of experience teaching the Sciences at KS3 to KS5, and Psychology at A-Level. Cara has taught in a range of secondary schools across the South West of England before joining the team at SME. Cara is passionate about Biology and creating resources that bring the subject alive and deepen students' understanding

Naomi Holyoak

Author: Naomi Holyoak

Expertise: Biology

Naomi graduated from the University of Oxford with a degree in Biological Sciences. She has 8 years of classroom experience teaching Key Stage 3 up to A-Level biology, and is currently a tutor and A-Level examiner. Naomi especially enjoys creating resources that enable students to build a solid understanding of subject content, while also connecting their knowledge with biology’s exciting, real-world applications.

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