24-11-2012, 02:44 PM
The phospholipids
The phospholipids.pptx (Size: 106.8 KB / Downloads: 24)
Membranes are composed of
phospholipids, is thin surface this is flexible
proteins is like spot on " in the phospholipids layer
Carbohydrates the carbohydrates extend out from the proteins.
All component arranged in a fluid mosaic structure
The phospholipids
Is bilayer (double layer)
hydrophilic(attractive water ) phosphate heads facing outwards
In middle of double layer is opposite outward
Different kinds of membranes have diffferent ability to allow substance basic on fatty acidy
function
Act as building blocks of the biological cell membranes
Act as efficient store of energy
semipermeable membrane because it can allow some things
The proteins
Almost reach two layer of phospholipid from one side \to the other (integral proteins)
Function is transporting substances across the membrane (
(peripheral proteins) sit in one layer
Function is attached to the cytoskeleton which maintained shape of cellor work as receptor by specilaize bind
function
Inter-cellular communication
The proteins is hydrophilic which allow to connect with water in out side
Is hydrophobic in contact with fatty acid inside (between bilayer)
Protein transporter which work as bind with specific material
Share in maintain shape
The carbohydrates,
The carbohydrates are found on the outer surface of all eukaryotic cell membranes,
Compose of mone accharide
Some times attack with protein or phospholipids and called glycop roteins or glycolipids
protection
cell recognition which cell communicate with other cells
antigens
Function of cell :
Cell membranes are a barrier to most substances
Control by substance enter and out of cell
there are five main methods by which substances can move across a cell membrane:
Lipid Diffusion
Osmosis
Passive Transport
Active Transport
Vesicles