BIOLOGIA

Apuntes

**G10** **Unit II: Transport Across Cells** **Atlas** **Extracted from IGCSE Biology Coursebook** **By: SEDDIK** • Subtopic: Diffusion and Related Diagrams There is a high concentration of hydrogen sulfide molecules in one corner. Given time, the molecules spread evenly through the space available. Figure 3.2: The random movements of gas molecules result in them spreading evenly through all the space available. Figure 3.3: This diagram shows how we can use the analogy of a slope to think about a concentration gradient. We can imagine particles moving down the slope, from a high concentration to a low concentration. Figure 3.4: Some substances, such as oxygen and carbon dioxide, move into and out of cells by diffusion through the cell membrane. • Subtopic: Osmosis Figure 3.5: How osmosis happens. It is important to think about the diffusion of each kind of molecule separately. Figure 3.6: We can think of a water potential gradient as a "slope." Water molecules have a tendency to move down the slope, from a high water potential to a low water potential. Figure 3.8: If an animal cell is placed in pure water, water enters the cell by osmosis. The cell ...