PLANT CELL TRANSPORT

• A plant cell has a cell wall, cell membrane, cytoplasm, nucleus, and other organelles

  
• A plant cell contains a vacuole that stores water, nutrients, and waste products

  
• Diffusion is the net movement of ions or solute molecules from a region of higher concentration to a region of lower concentration, down a concentration gradient
• Diffusion in gases involves gas molecules moving from a region of higher concentration to that of a lower concentration until they are evenly spread
• Diffusion in liquids occurs when dissolved particles of a substance in a liquid move from a region where they are more concentrated to a region where they are less concentrated
• Factors affecting the rate of diffusion include temperature, size of particles, thickness of the barrier, concentration gradient, and surface area
• Osmosis is the diffusion of water across a selectively permeable membrane, from a high water potential to a low water potential
• Osmosis is important in biology for maintaining water balance in cells and aiding in the transport of nutrients and waste products
• Osmotic potential (ΨS) is a measure of the potential of water to move from one cell to another as influenced by solute concentrations
• Turgor pressure in plant cells is the outward pressure exerted by the cell sap against the cell wall, helping maintain cell rigidity
• Plasmolysis is the loss of water through osmosis, leading to the shrinkage of protoplasm away from the cell wall
• Active transport is an energy-consuming process by which substances are transported from regions of low concentration to regions of high concentration against a concentration gradient
• Facilitated diffusion occurs when substances move through protein channels or carriers, allowing them to passively cross cell membranes without requiring energy input.
• The concentration gradient is the difference between the solute concentrations on either side of the membrane.
• Exocytosis refers to the release of materials outside the cell through fusion with the plasma membrane.
• Endocytosis involves the uptake of large molecules into the cytoplasm via vesicles formed at the plasma membrane.
• Passive transport does not require ATP and can occur downhill or uphill depending on the concentration gradient.
• Simple diffusion involves small nonpolar molecules that easily diffuse across the lipid bilayer.
• Simple diffusion is the passive movement of small nonpolar molecules (e.g., oxygen) across the lipid bilayer of the plasma membrane.
• DIFFUSION

  -LIVING CELLS CONTINUOUSLY USE UP OXYGEN DURING AEROBIC RESPIRATION.

  -THE CONCENTRATION OF OXYGEN INSIDE THE CELL FALLS.

  -OXYGEN MOLECULES DIFFUSE INTO THE CELL UNTIL THE OXYGEN CONCENTRATION IS RAISED AGAIN.

  -DURING RESPIRATION, CARBON DIOXIDE IS PRODUCED.

  -THE CONCENTRATION OF CARBON DIOXIDE RISES AND CREATES A CONCENTRATION GRADIENT
• : MEMBRANES OF PLANT AND ANIMAL CELLS ARE OF ABOUT THE SAME IN THICKNESS AND PERMEABILITY. PLANT CELL WALLS VARY IN THEIR THICKNESS. THE THICKER THE CELL WALLS, THE SLOWER THE RATE OF DIFFUSION.

  THICKNESS OF THE BARRIER
• water potential (Ψ)- measure of potential energy in water.

  EXPRESSED IN UNITS OF PRESSURE CALLED MEGAPASCALS (MPA)
• 2 types of cell transport: Active transport and Passive transport