Movement Through Cell Membrane

needs no energy because its the movement of biochemicals from an area of high conc. to an area of low conc. (Passive transport goes with the water current)

does require energy because its the movement of biochemicals from an area of low conc. to an area of high conc. (Active transport goes against the water current)

- Diffusion, Osmosis, and Active transport - how the cell takes in useful substances and removes waste products OR exchange in materials between a cell and its environment across a cell membrane

- particles that are free to flow/move - Diffusion is the movement of fluids from an area of high conc. to an area of low conc., until equilibrium is reached. - the particles in Diffusion move with (along) the concentration gradient & have the ability to go through a membrane but don't have to - e.g.'s of Diffusion without a membrane = dog farting + perfume aisle - e.g.'s of Diffusion with a membrane = gaseous exchange in the lung alveolus

is when a substances particles a spaced/spread out evenly, but the particles will still continue to move around

- the dog farting in the corner = the gas he releases is going from a place of high conc. (where the dog is) to a place of low conc. (the opposite corner of the room) until the particles reach equilibrium - the perfume aisle in a mall is highly concentrated with the scent of perfume when you're in it and then when you keep walking it will then be low in concentration

- the alveolus (gas-filled) in the lungs and the capillaries (blood-filled) do a gaseous exchange with each other across a membrane = the blood comes around the alveolus low in O2 and high in CO2, then the alveolus gives O2 to the blood and the CO2 goes into the alveolus which is Diffusion, and so the blood leaves high in O2 and low CO2 and can now give oxygen throughout the whole body

- Osmosis is the movement of water from an area of low conc. to an area of high conc., across a semi-permeable membrane (has to have a membrane) - movement of a solvent through a semi-permeable membrane from a region of lower conc. to a higher conc. of solute to equalize the concentrations of solute on both sides of the membrane

- the slice of potato in salt water = the potato has low conc. of water + salt inside it compared to the high conc. of water + salt that surrounds the potato (saltwater) - so the water inside the potato will go to where there is high conc. of salt which is on the outside in order to try and dilute it and so the particles will keep moving back and forth until equilibrium is reached

- allows some things to go through and not other things

- Solvent = the substance that is doing the dissolving (e.g. water) - Solute = the substance that is being dissolved (e.g. salt/sugar) - Solution = the solvent and the solute together (e.g. saltwater or sugarwater)

% change = ▲ mass / original mass x 100

- is the movement of substances against the concentration gradient + requires huge amounts of cellular energy to move substances from where they're low in conc. to where they're high in conc.

- plant roots in the soil = salts move from the soil where they're low in conc. to where they're high in conc. because the plant needs to drag in water to go to the leaves and photosynthesize so it can live, this is Active transport (Requires Energy) - salts are actively transported into the roots to make sure water continually enters the roots by osmosis (e.g. potato) - root cells must maintain a constant supply of cellular energy to move salt against the concentration gradient - (root hairs are everywhere)