CELLULAR TRANSPORT Chapter 7 Pages

Cell Transport The goal of cellular transport is to move substances into the cell that the cell needs and to remove wastes

Cell Membrane parts (this should be like your drawing in in your notes) Carrier Proteins Ion channels Cell Surface Markers What are these?

The Cell Membrane Fluid Mosaic Model Another term for the cell membrane. Phospholipids are not bonded together and can move (sideways, up/down) to give the membrane “fluidity” Selectively permeable

Transport There are two main types of transport Passive Transport: Does NOT require energy to move molecules across the cell membrane Active Transport: Requires energy to move molecules across the cell membrane

Transport Types Substances will move into and out of the cell membrane by PASSIVE TRANSPORT or ACTIVE TRANSPORT PASSIVE TRANPSORT Diffusion Osmosis Facilitated Diffusion ACTIVE TRANSPORT Na/K Pump Endocytosis Exocytosis ENERGY

Other Important definitions : Equilibrium: when the concentration of a substance is the same throughout a space Concentration gradient: the difference in concentrations of a substance across a space Permeability: the ability of a molecule to pass through a membrane depending on size, type, and make-up of membrane

Passive Transport The movement of molecules down the concentration gradient that does not require energy This is movement across a membrane

DIFFUSION HOW DOES DIFFUSION WORK? Process by which molecules move from an area of HIGH concentration to a LOW concentration No energy is needed

Diffusion Concentration: the amount of substance in an area Dynamic equilibrium: there is continuous movement of substances, but no overall change will happen

Diffusion Factors that can affect diffusion: pH Temperature Pressure Concentration of solute

Facilitated Diffusion Cells need to take in ions (Cl-) and small molecules (glucose) Uses Transport proteins Channel proteins: open and close to allow substances diffuse across the membrane

Facilitated Diffusion Carrier proteins: Change shape to pass substances through the membrane Remember…we are still moving from an area of HIGH concentration to an area of LOW concentration.

Osmosis The diffusion of water through a selectively permeable membrane How does this help maintain homeostasis? WATER is always the SOLVENT in the cell’s environment Concentration: measure of the amount of SOLUTE dissolved in a SOLVENT

Osmosis The water is moving from an area of HIGH water concentration to an area of LOW water concentration. There should be the SAME amount of water in both areas

What is the goal? What do we want to reach?

Definitions we need to know: ISO - equal HYPER - high HYPO - low TONIC – solution Environmental solution: outside of the cell

Osmosis – Isotonic Solution A solution with the same concentration of water and solute outside as it does inside the cell. (Iso = equal) Therefore…water does not need to go anywhere and will move in and out of the cell at an equal rate The cell retains its normal shape

Osmosis – Isotonic Solution

Osmosis – Hypotonic Solution A solution that has a lower concentration of solute outside than inside the cell (Hypo – LOW solute concentration) Therefore…There is more water outside than inside of the cell Water moves INTO the cell (so now both places are equal ) Cell will swell and even explode

Osmosis – Hypotonic Solution

Osmosis – Hypertonic Solution A cell that has a higher concentration of solute outside of the cell (Hyper – HIGH solute concentration) Water amount outside is lower than water inside Water moves out of the cell Cell will shrink or crenate

Osmosis – Hypertonic Solution

Passive Transport Recap Diffusion Osmosis Facilitated Diffusion

Active Transport Process in which energy is used to transport materials across the cell membrane It is AGAINST the concentration gradient The energy that is needed is called ATP Carrier proteins must be used

Active Transport continued … Types include Na/K Pump Endocytosis Exocytosis

Sodium Potassium Pump Found in animal muscle cells Maintains homeostasis by keeping the amount of Na+ and K+ balanced Na+ moves out K+ moves in Must use ATP since it is going against the concentration gradient Uses a transport protein

Sodium-Potassium Pump

Endocytosis Cell surrounds a substance and encloses it in a portion of the cell membrane Part of the cell membrane pinches off to form a vacuole Ex: Phagocytosis

Exocytosis The passage of large molecules outside of the cell Vesicle will expel wastes to the outside of the cell Example: secretion of hormones (opposite of endocytosis)

Endocytosis & Exocytosis