BOT3015 EXAM 3 Marking Scheme 2024 100% Correct

BOT3015 EXAM 3 Marking Scheme 2024 100% Correct Brownian movement - Answer- molecules /ions in constant random motion Diffusion - Answer- movement of molecules or ions from region of higher concentration to region of lower concentration Molecules that are moving from a region of higher concentration to a region of lower concentration are said to be moving ______________________________ - Answer- Along a diffusion gradient molecules moving from regions of low to high concentration are said to be moving ______________________ - Answer- against a diffusion gradient Equilibrium - Answer- When the molecules, through their random movement, have become distributed throughout the space available Rate of diffusion depends on several factors such as - Answer- pressure, temperature, and density Solvents - Answer- Are liquids in which substances dissolve Water (a solvent) moves freely from cell to cell semipermeable membrane - Answer- membranes through which different substances diffuse at different rates Osmosis - Answer- the diffusion of water through a semipermeable membrane from a region where the water is more concentrated to a region where it is less concentrated osmosis ceases if concentration of water on both sides of membrane becomes equal osmotic pressure - Answer- pressure that must be applied to prevent osmotic movement across a selectively permeable membrane osmotic potential - Answer- a measure of the potential of water to move from one cell to another as influenced by solute concentration Water gained by osmosis may keep a cell firm or ___________ - Answer- Turgid turgor pressure - Answer- pressure within a cell resulting from the uptake of water pressure potential (ΨP) - Answer- turgor pressure that develops against walls as a result of water entering the vacuole of the cell water potential - Answer- osmotic potential and pressure potential combined ___________ is primary means through which water enters plant from their surrounding environment - Answer- Omosis Osmosis steps - Answer- 1. Water from soil enters the cell walls and intracellular spaces of the epidermis and root hairs and travels along walls until it reaches endothermis 2. here it crosses differentially permeable mebranes and cytoplasm of the endodermal cells on its's way to xylem 3. Water flows from the xylem to the leaves, evaporates within the leaf air spaces, and diffuses out through stomata into the atmosphere 4. The movement of water takes place because there is a water potentil gradient from relatively high soil water potential to so succesively lower water potentials in roots, stems, leaves and the atmosphere Plasmolysis - Answer- the loss of water through osmosis, which is accompanied by the shrinkage of protoplasm away form the cell wall If plasmolyzed cells are placed in freshwater before permanent damage is done, water reenters cells through osmosis and cells become turgid Colloidal materials - Answer- materials that contain a permanent suspension of fine particles