Zusammenfassung der Ressource
B3.1 - Movement of Molecules In and
Out of cells
- Diffusion
- Particles move from an area of high
concentration to low
Anmerkungen:
- For example, different gases can simply diffuse through one another. Alternatively, dissolved particles can diffuse in and out of cells through cell membranes.
- The structure of leaves let gases diffuse in and out of cells
- Diffusion through cell membranes
- Gas exchange happens in the lungs
- The villi provide a really really big
surface area
- Osmosis
- Similar to diffusion, but only refers to water
- Water moves across a partially permeable membrane (eg. cell membrane)
from an area of high water concentration to low
- Active Transport
- Root hairs are specialised for
absorbing water and minerals
- Sometimes substances need to be
absorbed against a concentration gradient
- ie. from a lower to higher concentration
- Root hairs take in minerals
using active transport
- We need active transport to stop us starving