lesson 6: cell membranes

cell membranes are composed of

proteins & lipids

phosopholipids form the what of the cell membrane

the fundamental membrane structure

protiens provide what

membrane specific functions

carbohydrates in the outersurface of the plasma membrane form a what

a sugar coat which provides protection & facilitates cell-cell recognition

phospholipid structure

a polar hydrophilic head group, attatched to two nonpolar hydrphobic tails

phospholipid structures are

antipathic bc they contain hydrophobic and hydrophilic regions

selective permeability leads to

chemical differences between inside and outside of cell

two types of membrane protiens

integral and peripheral

factors that reduce membrane fluidity

1. lower tem

2. longer fatty acid chains

3. saturated fatty acid chains

integral membraine proteins are located where

embedded in phospholipid bilayer, ON BOTH SIDES OF MEMBRANE

how do you get rid of integral membrane protiens

you have to destroy the entire bilayer structure

integral membrane protiens are made of

transmembrane domains, 2025 mostly hydrophobic amino acid sequences that form a helix

integral membrane protiens can also be

lipid anchored, not made of transmembrane protiens

osmosis

water tends to move down its concentration gradient and surround solutes

solute concentration may

differ on two sides of the cell membrane, this influences movement of water

osmotic pressure

the force needed to stop osmosis

endocytosis

allows eukaryotic cells to ingest larger material from extracellular environment

pinocytosis

(cell drinking) , non selective update of water and macromolecules

receptor-mediated endocytosis

receptor protien binds, specific molecule targets, slective uptake of necessary molecules

phagocytosis

selective engulfment of another cell

peripheral membrane protiens

non covalent bound to transmembrane protiens or phosphilipid heads, ONLY ONE ONE SIDE

perphiral membrane protiens can be removed from membrane without destroying membrane structure

removed from membrane without destroying membrane structure