Further into the cell membrane. What makes up the cell membrane? A)Phospholipid bilayer a)Hydrophilic head (water-loving) towards the outside 1) Phosphate.

further into the cell membrane

Cell Transport

Cell MembraneWhat makes up the cell membrane?

A) Phospholipid bilayera) 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 meltingC) Carbohydrates

a) Help stabilize the membrane structureD) 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?

Plasma/ Cell

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

oil.

Cell membrane is…

Selectively permeable, what does that mean?

>>Some substances can pass across them and others cannot

Cell membranePhospholipids bilayer

Made of a negatively charged phosphate “head”PO4

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 chainsHydrophobic= don’t like waterSo the inside of the cell membrane

doesn’t let water in but the outside allows cells to be dissolved in aqueous environments

Passive Transport

•The movement of materials across the cell membrane without using cellular energy

Active Transport• The movement of materials against a concentration difference

Passive Transport:Diffusiono 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.

Passive Transport: Facilitated Diffusion

o Uncharged ions easily pass through the lipid bilayer through diffusiono 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 channelso Red Blood cells and glucose

Passive Transport:Osmosis 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 cellHypotonic: 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

Passive Transport Review

NO ENERGY REQUIRED!

Active Transport Movement of materials against a concentration difference

Requires Energy

Carried out by proteins or protein pumps

Active Transport:Molecular Transport

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

Active Transport: Bulk Transport

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