Study Notes
Transport in plants involves the movement of substances like water, minerals, and food through specialized structures. Diffusion — the net movement of molecules from a region of higher concentration to a region of lower concentration down a concentration gradient. Example: Oxygen diffusing into cells for respiration. Osmosis — the diffusion of water molecules through a partially permeable membrane from a region of high-water potential to low water potential. Example: Water entering plant cells making them turgid. Transpiration — the process of water evaporation from the surface of leaves. Example: Water vapor exiting through stomata. Xylem — transports water and mineral salts from the roots to all parts of the plant. Example: Water moving from roots to leaves. Phloem — transports food made in the leaves to all parts of the plant. Example: Sugars moving from leaves to roots.
Exam Tips
Key Definitions to Remember
- Diffusion: Movement of molecules from high to low concentration.
- Osmosis: Movement of water through a partially permeable membrane.
- Transpiration: Evaporation of water from plant leaves.
- Xylem: Transports water and minerals.
- Phloem: Transports food.
Common Confusions
- Diffusion vs. Osmosis: Diffusion involves all molecules, osmosis specifically involves water.
- Turgid vs. Flaccid: Turgid cells are swollen with water, flaccid cells are not.
Typical Exam Questions
- What is diffusion? Movement of molecules from high to low concentration.
- How does osmosis affect plant cells? Water enters or exits cells, making them turgid or plasmolyzed.
- What is the role of xylem in plants? Transports water and minerals from roots to other parts.
What Examiners Usually Test
- Understanding of diffusion and osmosis processes.
- Differences between xylem and phloem functions.
- Effects of different solutions on plant cells (turgid, flaccid, plasmolyzed).