Cambridge IGCSE Combined Science, topic 3
Movement into and out of cells
Cells must take in the substances they need and get rid of the substances they do not. This topic covers the three ways substances cross cell membranes: diffusion, osmosis and active transport. You also need to know how to investigate them, and how water movement keeps plant cells firm.
Revision notes
Worksheet
FlashcardsSubtopics
Work through them in order. Each one has notes, exam questions and flashcards, and a PDF of each. Subtopics that are not in 0653 are left out.
- 1Diffusion Spec B3.1Diffusion is the net movement of particles down a concentration gradient; learn why it matters and what changes its rate.NotesQuestions 4Flashcards 6
- 2Osmosis Spec B3.2Osmosis is the diffusion of water through partially permeable membranes; water potential, turgor and plasmolysis explain what happens to plant cells.NotesQuestions 4Flashcards 10
- 3Active transport SupplementSpec B3.3Active transport moves particles against a concentration gradient using energy from respiration and protein carriers.NotesQuestions 4Flashcards 4
Whole topic
When you have done the subtopics: test yourself on everything, or print the lot.