BIO 181 Lecture : BioNotes1_30_13.docx
Document Summary
Active energy required; goes against concentration gradient. Movement of molecules of molecules/ions from areas of high concentration to low concentration; no energy input required. Passive transport: molecules have kinetic energy, which makes the ions move around randomly. Over time, molecules will move from an area of high concentration to be evenly spread out. Hydrophobic molecules cross membranes easily, while hydrophilic molecules do not. Water passes through membranes easily party due to aqua porins. Solute concentrations: how many molecules are dissolved in water or other solvents: hypotonic, hypertonic. Cells behave differently in different solutions (red blood cell example: distilled water water moves into cell to achieve equilibrium; concentrated salt solution water movies out of cell to achieve equilibrium. Facilitated diffusion diffusion through protein channels, still a passive form of transport. Difference is that molecules go through protein channels instead of phospholipids. Two types one uses channel proteins, other uses carrier proteins.
