2. How does the polarity of water make hydrogen bonding possible? Water is a polar molecule slightly positive end (H) and slightly negative end (O) because electrons spend more time in orbit around larger O molecule H’s of one water molecule are attracted to O’s of another Form Hydrogen bonds H-bonds are usually weak, but are unusually strong in water Gives water several important properties
4. How are the 3 properties important in cells and organisms? 3 important properties: Cohesion Water molecules stick together Surface tension, blood Adhesion Water molecules stick to other things Capillary action High Specific Heat Water resists changes in temperature Chemical reactions produce a lot of heat Maintains homeostasis
5. What is blood? Liquid part is called plasma About 95% water Also includes red blood cells, white blood cells, platelets, sugars, proteins, etc.
6. Water as a Solvent Water is an excellent solvent, but not the “universal solvent” as commonly called Water readily dissolves polar substances and ionic compounds Sugars, proteins, salts Water does not dissolve nonpolar substances Fats, oils
8. Other components of the Cell Membrane Proteins Aid in transport of materials in and out of cell Anchor cell membrane to cytoskeleton Carbohydrate chains Identify cells Cholesterol Strengthen membrane
9. How is the cell membrane like a window screen? Selective Permeability It allows some molecules to pass through it but not others Some molecules need an opening, like a transport protein
10. Cellular Transport Two types Passive transport Particles move from higher concentration to lower concentration, requires no cellular energy Diffusion, facilitated diffusion, osmosis Active Transport Particles move from lower concentration to higher concentration, requires cellular energy Pumps, endocytosis, exocytosis
14. Active transport in the body Sodium-Potassium Pumps Help your nerve cells to function Pump sodium ions out of and potassium ions into cell Endocytosis Cell eating and drinking (single-celled organisms) Exocytosis Cell secretions, waste disposal
