Biology Notes

Biology Notes Structure of a cell membrane -CORRECT ANSWER- Bilayer of phospholipids with embedded and attached proteins- fluid mosaic Fluid mosaic -CORRECT ANSWER- A description of membrane structure, depicting a cellular membrane as a mosaic of diverse protein molecules embedded in a fluid bilayer made of phospholipid molecules. Aquaporin -CORRECT ANSWER- Water transport channels that allow for very rapid diffusion of water through a cell membrane. Single allows up to 3 billion water molecules per second. Found in cells that have high water transport needs (blood cells, kidney cells, & plant cells) Unsaturated fatty acid -CORRECT ANSWER- A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton. Selective permeability -CORRECT ANSWER- Membranes that allow some molecules to pass through more easily than others Transport proteins -CORRECT ANSWER- A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane. Glucose -CORRECT ANSWER- Requires a transport protein to enter of leave the cel Phospholipids -CORRECT ANSWER- Part of the membrane structure and function of the cell. A molecule that is a part of the inner bilayer of biological membranes, having a polar hydrophilic head ,and a non-polar hydrophobic tail. Hydrophilic -CORRECT ANSWER- "Water-loving"; pertaining to polar (charged molecules), or parts of molecules, that are soluble (dissolve) in water. Head=polar Hydrophobic -CORRECT ANSWER- "Water-fearing"; pertaining to nonpolar molecules, or parts of molecules, that do not dissolve in water. Tail=non-polar Unsaturated -CORRECT ANSWER- Double-bonds, kinks don't allow for compaction Saturated -CORRECT ANSWER- Single-bonds, tightly packed Cholesterol -CORRECT ANSWER- In between the tails Stable membrane -CORRECT ANSWER- Hot temperature Flexible membrane -CORRECT ANSWER- Cold temperature Thermal motion -CORRECT ANSWER- Heat. Molecules vibrate and move randomly Diffusion -CORRECT ANSWER- The tendency for particles of any kind to spread evenly in an available space. Process: molecules move from an area of higher concentration to an area of lower concentration Concentration gradient -CORRECT ANSWER- When gradient exits substances tend to move from there they are more concentrated to where they are less concentrated Passive transport -CORRECT ANSWER- Cells that do not have to do work when molecules diffuse across its membrane. Simple diffusion. Without energy. SImple diffusion -CORRECT ANSWER- Unassisted diffusion of solutes through the plasma membrane Factors affecting diffusion rate -CORRECT ANSWER- Temperature- temp rides & speeds up motion of molecule. Molecular