Membrane structure ,synthesis ,transport 
Membrane structure
Phospholipid are amphipathic
Fluid-mosaic model
Membrane is phospholipid bilayer contain also protein and carbohydrates
Hydrophobic
Hydrophilic
Region faces out
Protein bound to membrane
Mosaic
Fluid
Lipid , protein , carbohydrates
Lipids and proteins can move
Integral membrane protein
Extrinsic membrane protein
Transmembrane proteins
Lipid-anchored proteins
Non Covalenty bound
Region faces in
fluidity of membrane
Flippase requires ATP
Lipid rafts
Flip-flop of lipids
Factors affecting fluidity
Rotation = move laterally
Membrane are semi fluid
Lipids associate with each othe and form it
Group of lipids floats together as a unit
Composition
Unique set of membrane proteins
Play role in endocytosis and cell signaling
High concentration of cholesterol
Presence of double bonds
Presence of cholesterol
Length of fatty acrylic tails
Synthesis of membrane components
Transfer of lipids to other mambrane
Synthesis of transmembrane proteins
Process occurs at cytosolic leaflet of the smooth ER
Glycosylation
Fatty acid building blocks are made via enzyme in cytosol
Transported via vesicles
Lipid exchange proteins
Lipids in ER membrane can diffuse laterally to nuclear envelop
Most tensmembrane proteins are directed to the ER membrane first
Membrane protein can be transferred via vesicles to other membrane
Process attaching a carbohydrate to protein or lipid
Glycolipid
Glycoprotein
Carbohydrate to lipid
Carbohydrate to protein
N-linked Glycosylation
O-linked Glycosylation
Attachment ofcarbohydrate to nitrogen atom of asparagine
Occur in ER
Addition of sugars to O atom of serine or threonine side chain
Occurs in Golgi
Membrane transport
Cells maintain gradients
Phospholipid bilayer barrier
Tonicity
Way to move o cross membranes
Osmosis
Plasma membrane is selectivity permeable
Transport protein
Passive transport
Active transport
Facilated diffusion
Require energy - up or against gradient
Passive diffusion
Diffusion of a solute through a membrane without transport protein
Diffusion of a solute through a membrane with the aid of a transport protein
Rate of diffusion
Example ; diethylurea
Hydrophobic interior
Transmembrane gradient
Ion electrochemical gradient
Hypertonic
Hypotonic
Isotonic
Equal water and solute concentration in both side
Solute concentration is higher and water concentration lower on one side
Solute concentration is lower and water concentration higher on one side
Osmotic pressure
Osmosis in animal cells
Water diffuses
Osmosis in plant cells
Crenation
Osmotic lysis
Maintain a balance between extra cellular and intracellular solute concentration
Shrinkage
Swelling and bursting
Turgor pressure
Plymolysis
Cell wall prevent major change in cell size
Pushes plasma membrane against cell wall
Plant wilting because water leaves plant cells
Type of movement
Large molecule transport :
Channels
Transporters
Open passageway for direct diffusion of ion or olecules across the membrane
Example ; Aquaporins
Conformational change transport solute across membrane
Such as ; Sugar , amino acid , nucleotides
Transporter types
Uniporter
Symporter
Antiporter
Single molecule or ion
Two or more ion or molecule transported in same direction
Two or more ions or molecules transported in opposite direction
Active transport
Movement of the solute across a membrane against its gargient
Type of active transport
Require energy (ATP)
Primary active transport
Secondary active transport
Exocytosis
Endocytosis
Material inside the cell packaged intro vesicles
Pinocytosis
Phagocytosis
Receptor- mediated endocytosis
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