Cell Transport Passive and Active

 Plasma Membrane = “selectively permeable”  (lets certain things in & keeps others out)  Plasma membrane is used to maintain homeostasis (maintain a constant internal environment)

 I. Passive Transport= movement of a substance through a cell membrane without using any energy 1. Diffusion= movement of particles from high concentration to low concentration difference in concentration is called a concentration gradientdifference in concentration is called a concentration gradient diffusion occurs until equilibrium is reacheddiffusion occurs until equilibrium is reached

2.) Osmosis= diffusion of water through a selectively permeable membrane from an area of high water concentration to an area of low water concentration Solute = a substance dissolved in another substance (ex. Kool-Aid) Solute = a substance dissolved in another substance (ex. Kool-Aid) Solvent = a substance that does the dissolving (ex. Water) Solvent = a substance that does the dissolving (ex. Water) Solution = mixture of solutes & solvents Solution = mixture of solutes & solvents

 Isotonic Solution = concentration of solutes is same inside & outside of a cell (at equilibrium)

 Hypotonic Solution = low solute, high solvent Ex. Cell swells when placed in a hypotonic solution – cell lysis (explodes) Ex. Cell swells when placed in a hypotonic solution – cell lysis (explodes)

 Hypertonic Solution = high solute, low solvent Ex. Cell shrinks when placed in a hypertonic solution – cell crenation Ex. Cell shrinks when placed in a hypertonic solution – cell crenation

 iso, hypo, & hyper refer to the solutes!! Isotonic hypotonichypertonic

 Facilitated Diffusion = transport of particles through a membrane by a channel protein (No energy needed!)  II.) Active Transport = using energy to transport particles through a membrane against a concentration gradient (lesser concentration to greater concention)

Active Transport

Types of Cellular Transport  Active Transport cell does use energy 1. Protein Pumps 2. Endocytosis 3. Exocytos  Passive Transport cell doesn’t use energy 1. Diffusion 2. Facilitated Diffusion 3. Osmosis high low This is gonna be hard work!! high low Weeee!! !

Active Transport cell uses energy actively moves molecules to where they are needed Movement from an area of low concentration to an area of high concentration (Low  High) Three Types:

Types of Active Transport 1. Protein Pumps - transport proteins that require energy to do work Example: Sodium / Potassium Pumps are important in nerve responses. Sodium Potassium Pumps Sodium Potassium Pumps (Active Transport using proteins) Protein changes shape to move molecules: this requires energy!

Types of Active Transport  2. Endocytosis: taking bulky material into a cell Uses energy Uses energy Cell membrane in-folds around food particle Cell membrane in-folds around food particle “cell eating” “cell eating” forms food vacuole & digests food forms food vacuole & digests food This is how white blood cells eat bacteria! This is how white blood cells eat bacteria!

Types of Active Transport 3. Exocytosis: Forces material out of cell in bulk membrane surrounding the material fuses with cell membrane membrane surrounding the material fuses with cell membrane Cell changes shape – requires energy Cell changes shape – requires energy EX: Hormones or wastes released from cell EX: Hormones or wastes released from cell Endocytosis & Exocytosis Endocytosis & Exocytosis animations

How well did you do today?  Molecules move from areas of low concentration to areas of high concentration through the process of A. osmosis. B. diffusion. C. passive transport. D. active transport.