Cell membranes (unit 2)

Cell
Membranes

, SUMMAR Y
· Membranes consists of : lipids
Proteins
Carbohydrates


· FLUID MOSAIC MODEL

phospholipid bilayer
Where Proteins can move Within the Plane of the Membrane



· Properties of a membrane depends on :



non polar lipids
integral Membrane Proteins valine ,
alanine ,
leucine
,
isoleucine

Peripheral Membrane Proteins

anchord Membrane Proteins




if a cell is incubated in a nonpolar detergent
~ lipids of cell Membrane will dissolve

~
Cytoplasm will be released into the solution

,For cells to assemble into tissues :



↓
Cell recognition cell adhesion




Cell junction w connects to adjacent cells




tight junstions a prevents the passage of Molecules
through intercellular spaces



~
restrict the movement of

Membrane proteins




deSMOSOMeSn helps cells to adhere firmly




gap junctions w communication between adjacent cells

, Membranes by passive processes
· selective permeability
< witch
determines substances can pass through




· diffusion
^ channel
-
Movement of a solute from a region of Protein
high concentration
carrier
& low concentration
- protein

· OSMOSIS
Water Moves across a Membrane

from a high solute concentration

to a low concentration




· isotonic
concentration on both sides of Membranes =




hippo enters the water
* hippo
· hypotonic
More water enters the cell then leaves


· hipertonic
More water leaves the cell them enters