The Cell & Cell Processes

I.Factoids A. You have approximately 7.5 TRILLION cells that make you up. B. 200 different types of cells work together and form the tissues that make up our organs.

II. Cells are specialized A. Cells in the body have different functions so the shape & amount of organelles depends on the function of the cell.

Mitochondria Transforms food molecules into energy for cell

Cytoplasm Liquid material that organelles reside in. Cellular metabolism occurs here.

Lysosome Contains enzymes that break down molecules

Plasma (Cell) Membrane 1. Barrier of the cell that is semi (or selectively) permeable a) Regulates in/out of cell 2. 3/10,000,000 of an inch thick 3. ALL cells have a P.M. outside membrane inside

III. Membrane transport A. Solution: mixture of 2 or more components 1. Ex: seawater B. Solvent: present in the largest amount, what something is dissolving in. 1. Ex: water C. Solute: what dissolves into the solvent 1. Ex: salt

D. Intracellular fluid: fluid in the cell w/ gasses, salts & nutrients E. Interstitial fluid: fluid that bathes the outside of the cell. 1. Has thousands of ingredients (sugars, amino acids, fats, vitamins, hormones, salts, waste products)

IV. Cell Transport Methods A. 2 types of movement across the plasma membrane: 1. Passive: requires no energy 2. Active: requires energy

B. Passive transport 1. Diffusion: substance moves from higher to lower concentration to balance a. The difference between the 2 concentrations is the concentration gradient

2. Osmosis: water moves from a higher to lower concentration to balance. a. Solute: substance dissolved in water BEAKER example

Draw the beaker on a sheet of paper. Top or side view. Draw a drop of food dye on one side of the beaker & the overall direction the dye will move will diffuse to. Draw the overall direction water will move to due to osmosis.

Osmosis of water moves in the opposite direction of diffusion of solute.

3. Facilitated Diffusion: substance is helped across a membrane. a. Substance already trying to get in, uses “gates” in the P.M.

4. Filtration: pressure (from heart beating) is applied to force water and it’s dissolved materials across a membrane.

C. Active Transport 1. Require ATP (adenosine triphosphate) energy. 2. Active Transport Pumps a. Needed b/c the cell is trying to move a substance against the concentration gradient.

3. Endocytosis a. Intake of food (or water) when the quantity is too large to pass through the membrane. b. Membrane surrounds and pulls substance in. i.Phagocytosis- solid material

4. Exocytosis a. Transport of substances outside of the cell.