❖Cell/Plasma Membrane  Regulates what enters and leaves the cell and provides protection and support.  Phospholipid Bilayer  Selectively Permeable ❖Cell/Plasma Membrane  FIRST color the phospholipid bilayer!  Blue – phosphate heads  Red – lipid tails  Purple - protein I. Passive Transport – when the cell does not require energy to move molecules across a membrane.  Movement from high to low concentration (conc.) Diffusion Definition Particle movement from an area of high concentration to an area of low concentration. Vocabulary Equilibrium – when the concentration of the solute is the same throughout a system. Hot Water Cold Water Room Temp. Water • How does temperature affect diffusion? • Why is a warm body advantageous to a living thing? Diffusion Picture Examples Osmosis Definition Vocabulary The diffusion of water through a selectively permeable membrane. • Isotonic – The concentration of solutes is the same inside and outside the cell • Hypotonic – solution has a lower solute concentration than the cell. • Hypertonic – solution has a higher concentration of solute than the cell Osmosis Picture Examples • Fill this in after GummyBear Lab! Facilitated Diffusion Definition Movement of specific molecules across cell membranes through protein channels Vocabulary Protein channel – act as “doorways” for larger molecules, and allow certain molecules to cross membrane Facilitated Diffusion Picture Examples • Red blood cells have a cell membrane protein that allows glucose to pass through it. • Does not need energy! 2. Active Transport – energy-requiring process that moves material across a cell membrane against a concentration difference. Molecular Transport Definition When small molecules and ions are carried across membranes by proteins in the membrane that act like energy-requiring pumps Vocabulary Needs ENERGY! Moves from low concentration to high concentration Molecular Transport Picture Examples • Many cells move calcium, potassium, and sodium across cell membranes Endocytosis Definition • Process of taking material into the cell by means of infoldings, or pockets, of the cell membrane Vocabulary • • Phagocytosis – “cell eating” extensions of cytoplasm surround and engulf large particles and take them into the cell Pinocytosis – cell takes in liquid from the surrounding environment Endocytosis Picture • See previous slide. Examples • Amoeba’s use endocytosis to get their food Exocytosis Definition • Process by which a cell releases large amounts of material Vocabulary • None Exocytosis Picture Examples • Cell can get rid of waste or cellular materials this way 1. 2. 3. 4. 5. 6. A cell membrane encloses and takes in a drop of fluid. Carrier proteins use energy and act as a pump to move nutrients into a root cell. Carrier proteins take sugar (glucose) into a cell without requiring energy input. Water diffuses across a cell membrane from a region of high concentration to a region of low concentration. Mucus and waste products packaged by Golgi apparatus are secreted by a cell. A cell membrane encloses and takes in large food particles. Passive or active? Passive or active? Passive or active? Food particle Amoeba Passive or active? Passive or active? Passive or active? 1. 2. 3. 4. 5. 6. 7. Obtain a piece of red onion, slide and cover slip. Create a wet mount slide with water. Observe the appearance of the cells under the microscope. Use toweling method to add several drops of salt water. Observe the appearance of the cells under the microscope. What happened? Why? Before Salt Water After Salt Water