Homeostasis: Active & Passive Transport

Which way will water move Type of solution What is it Which way will water move What happens to a cell placed in the solution? Hypertonic More solute outside the cell than inside the cell Outside the cell Shrink Hypotonic More solute inside the cell than outside the cell Inside the cell Swell Isotonic Equal concentration of solutes inside and outside the cell Movement of water is equal nothing

Movement of water What will happen to a cell that is too hypertonic? The cell will shrink What will happen to a cell that is too hypotonic? The cell will burst!

Transport What does transport mean? How many kinds are there? The movement of something How many kinds are there? 2 What are they called? Passive transport and active transport

Passive Transport Definition: Movement of particles through the plasma membrane with no energy Particles move down the concentration gradient What does this mean? Particles move from an area of high concentration to low concentration *(think of the tennis ball example)

Facilitated Diffusion Definition: passive transport of materials across the membrane using transport proteins Channel proteins: form channels allowing specific molecules to flow through Carrier proteins: change shape to allow a substance to pass through the plasma membrane

Specialized Passive Transport The movement of any molecule across a selectively permeable membrane with the concentration gradient is referred to as Diffusion. The movement of H20 across a selectively permeable membrane with the concentration gradient is referred to as Osmosis.

Active Transport Definition: Movement of particles through a membrane against a concentration gradient ***REQUIRES ENERGY!!!!!!!! ***:O Which way do particles move?? LOW concentration to HIGH concentration

Active Transport Uses carrier proteins to move particles against the concentration gradient

Passive vs. Active transport Type of transport Transport protein used Direction of movement Requires energy input from cell? Classification of transport Simple diffusion No Down the concentration gradient Passive Facilitated diffusion Yes-channel and/or carrier proteins Active transport Yes-carrier proteins Against the concentration gradient yes Active

Transport of large particles Endocytosis: Cell surrounds and takes in material from the environment (Enters) Exocytosis: Cell expels (releases) material from a cell (usually to remove wastes) (Exits)

What are buffers? Buffers are essential for many biochemical processes. It serves to maintain the correct pH and temperature necessary as many enzymes work only under precise pH and temperature conditions. Without buffers necessary chemical reactions in cells would not happen resulting in cell death.