Movement In And Out Of Cells PDF

1. Introduction to biology 1. Classification 2. Cells 3. Movement in and out of cells Types of movement across membrane  diffusion  osmosis  active transport Diffusion  the net movement of molecules and ions from a region of their higher concentration to a region of...

1. Introduction to biology 1. Classification 2. Cells 3. Movement in and out of cells Types of movement across membrane  diffusion  osmosis  active transport Diffusion  the net movement of molecules and ions from a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of their random movement Diffusion in animals  oxygen from the air into blood in the lungs  carbon dioxide from blood in the lungs  absorption of some of the products of digestion in the small intestine Diffusion in plants  carbon dioxide from the air into the leaves  oxygen out of the leaves Solution  liquid consisitng of a uniform mixture of two or more substances  solvent: the dissolving agent  solute:a substance that is dissolved  aqueous solution: one in which water is the solvent Osmosis http://highered.mheducation.com/sites/007249 5855/student_view0/chapter2/animation__how _osmosis_works.html Osmosis  the diffusion of water molecules from a dilute solution to a region of concentrated solution, through a partially permeable membrane Partially permeable membrane  lets some molecules through but not others  usually because of their size Consequences of osmosis  animal cells  in dilute solutions take up water, swell and eventually burst  in concentrated solutions lose water and shrink Consequences of osmosis  plant cells  indilute solutions take up water and swell, but they do not burst  the cell wall prevents the cell from bursting  thecell is turgid: it is tight and firm Consequences of osmosis  plant cells  in concentrated solutions lose water and the vacuole shrinks  thecell membrane tears away from the cell wall: plasmolysis  the cell is flaccid: not tight Active transport  the movement of molecules through the cell membrane against a concentration gradient, using energy  used when cells need substances present in small quantities around them root hairs take up ions from the soil glucose absportion in the small intestine Active transport  requires special transport proteins called pumps