A multicellular aquatic organism can grow in either a compact form or a branching form. A scientist models both forms using cube-shaped sections. In the branching form, water-filled spaces expose every section to the surrounding water.
Dissolved oxygen enters the organism through its body surface by diffusion.
| Form | Number of identical sections | Exposed surface area of each section in mm² | Total volume in mm³ |
|---|---|---|---|
| Compact | 1 | 600 | 1000 |
| Branching | 125 | 24 | 1000 |
Calculate the surface area to volume ratio of each form.
Explain which form is more likely to need an internal transport system for oxygen.
140 exam-style questions on AQA GCSE Biology 1.3 Transport in cells, covering 1.3.1 Diffusion, 1.3.2 Osmosis, and 1.3.3 Active transport. Each one has a worked solution and a mark scheme showing where the marks go.