Cell boundaries -and cell transport-

The Cell Membrane The cell membrane is a selectively permeable, fluid mosaic, phospholipid bilayer!

The Cell Membrane selectively permeable - some stuff can get in (water); other stuff cannot get in without help (big molecules and charged molecules)

molecules are in constant motion The Cell Membrane fluid means the molecules are in constant motion Mosaic means it is made of individual pieces that form the membrane

The Cell Membrane Phospholipid – phosphate and lipid bilayer - 2 layers of phospholipids; hydrophobic tails pointed inward

The Cell Membrane Also has protein tunnels and channels, carbohydrate "markers", and many other embedded molecules

The Cell Membrane Functions: 1. regulates what enters & exits the cell 2. protection 3. support

Found in: plants algae fungi bacteria The Cell Wall Function: -support -protection Found in: plants algae fungi bacteria

Passive transport (no energy required) Active transport Cell transport Moving small particles: Passive transport (no energy required) Active transport (energy required)

Moving small particles: Cell transport Moving small particles:

Cell transport Passive Transport: Diffusion: movement of molecules from an area of high concentration to an area of low concentration

Cell transport Passive Transport: Diffusion:

Passive Transport: Diffusion examples: Air freshener Fresh baked bread Cell transport Passive Transport: Diffusion examples: Air freshener Fresh baked bread Smelly candle

Passive Transport: Osmosis: the diffusion of water Cell transport The water moves from high to low concentration

Passive Transport: Cell transport Osmosis: the side with less sugar has a higher concentration of water

Passive Transport: (osmosis) Cell transport Passive Transport: (osmosis) Water will move across the membrane until equilibrium is met -Both solutions are isotonic

Cell transport Passive Transport: (osmosis) If the conc. of water outside is greater than solutes-it is a hypotonic condition

There is net water movement into the cell. Cell transport Passive: (osmosis) If the conc. of water outside is greater than solutes-it is a hypotonic condition There is net water movement into the cell.

Cells without walls = swell & burst Cell transport Passive: (osmosis) If the conc. of water outside is greater than solutes-it is a hypotonic condition There is net water movement into the cell. Cells without walls = swell & burst Cells with walls = benefit from the turgor pressure

Cell transport Passive: (osmosis) If concentrations of dissolved solutes are greater outside the cell, the concentration of water outside is lower- Hypertonic

Cell transport Passive: (osmosis) If concentrations of dissolved solutes are greater outside the cell, the concentration of water outside is lower- Hypertonic Water inside the cell will flow outwards to attain equilibrium = cell shrinks

Passive Transport: (osmosis) Cell transport Passive Transport: (osmosis)

Passive Transport: Osmosis examples: Cell transport Drop of food coloring added to a cup of water Wilted plant “perks” up after given water

Passive Transport: Facilitated Diffusion: Cell transport Passive Transport: Facilitated Diffusion: -Protein channels that make it easy for some large molecules (glucose) to fit through the membrane -Still diffusion (no E)

Active Transport: Cell transport movement from an area of low to high concentration NEEDS ENERGY (ATP)

the opposite of diffusion Cell transport Active Transport: the opposite of diffusion proteins will help move molecules across the membrane using ATP

Cell transport Active Transport: Endocytosis : the movement of large particles into a cell by enclosing around it

Cell transport Active Transport:

Cell transport Active Transport: Exocytosis: cell releases a particle by wrapping it in a vesicle then moves to the cell membrane

Transport through a membrane sTrtsrsan Transport through a membrane Ac Ac PASSIVE ACTIVE NO ENERGY Ac Ac ENERGY Ac Ac endocytosis LargeAc Ac diffusion osmosis exocytosis