further into the cell membrane

What makes up the cell membrane? A)Phospholipid bilayer a)Hydrophilic head (water-loving) towards the outside 1) Phosphate group b)Hydrophobic tail (water-fearing) towards the inside 1)Fatty acid chain B)Cholesterol a)Keeps the cell fluid, prevents it from freezing or melting C)Carbohydrates a)Help stabilize the membrane structure D)Proteins a)Variety of functions 1)Transport proteins 2)Enzymes E)Fluid Mosaic Model -Many proteins and carbohydrates are also found among the lipid bilayer (Proteins embedded in lipid bilayer, Carbohydrates attached to proteins) - So many different molecules in membrane, we call it a “mosaic” of different molecules -Mosaic- kind of art that involves bits and pieces of different materials and colors.

Mosaic model?

The membrane is fluid, and the molecules are always moving. It has about the same consistency as olive oil.

Selectively permeable, what does that mean? >>Some substances can pass across them and others cannot

Phospholipids bilayer Made of a negatively charged phosphate “head” PO 4 3- Attracts water because the phosphate is charged (-) Water is a polar, slightly positive ends and slightly negative ends Attached to the phosphate group are 2 fatty acid chains Hydrophobic= don’t like water So the inside of the cell membrane doesn’t let water in but the outside allows cells to be dissolved in aqueous environments

The movement of materials across the cell membrane without using cellular energy The movement of materials against a concentration difference

o In any solution, solute particles are constantly moving, colliding, and randomly spreading apart. o The particles (solute) move from an area of more concentration to an area of less concentration.

o Uncharged ions easily pass through the lipid bilayer through diffusion o What about larger molecules with a charge? o Process in which molecules that cannot directly diffuse across the membrane pass through special protein channels o Proteins act as carriers or channels o Red Blood cells and glucose

o Osmosis is a type of facilitated diffusion. o Osmosis is the diffusion of water through a selectively permeable membrane. o Water moves instead of the solutes from higher concentration to lower concentration.

Hypertonic: Solution has a higher solute concentration than the cell Hypotonic: Solution has a lower solute concentration than the cell Isotonic: The concentration of solutes is the same inside and outside the cell.

 Reminder: In osmosis the water is moving, not the solutes

NO ENERGY REQUIRED!

 Movement of materials against a concentration difference  Requires Energy  Carried out by proteins or protein pumps

Protein pumps: - Energy from ATP is used to pump small molecules and ions across the cell membrane. -Change shape during the process - sodium-potassium pump Carrier proteins: -Specific - not an open pathway like the protein pumps -Both use energy in the form of ATP - Both go from low concentration to high concentration

Endocytosis-  Taking into the cell  infolding or pockets off the cell membrane  Phagocytosis- extensions of cytoplasm surround the particle and package it within a food vacuole.  Pinocytosis- brings water into the cell from the exterior Exocytosis-  Taking out of the cell

What is the below an example of? The effect on Osmosis on cells: Egg Lab