Cell Membrane Flashcards
also called the plasma membrane
cell membrane
[functions of plasma membrane]
Channels, pumps
Transport of molecules
[functions of plasma membrane]
Engulfing particles
Phagocytosis, pinocytosis
[functions of plasma membrane]
Due to presence of carbohydrates
Cell to cell communication
[functions of plasma membrane]
Cell membrane-bound receptors, enzymes and proteins
cell signaling
protects the cellular organelles
Plasma memberane
[functions of plasma membrane]
Segregates one part of the cell from other
Compartmentalization
Membrane modification for specialized functions
Myelin sheath of neurons, microvilli in the intestine
“Small, nonpolar molecules get in
ions and polar molecules don’t get in.”
Selective Permeability
It separates interior of cell from the outside environment
Cell membrane
Selectively permeable
Regulates entry
Responds to stimuli
Cell membrane
year when it was discovered
1890
year when the components were described
1915
year when nicolson ans singer proposed what cell membrane looks like
(Fluid Mosaic Model)
1972
What model?
Flexible not like the rigid cell walls
Can change shape
Similar with a mosaic art, it is also made up of different molecules namely phospholipids, proteins, carbohydrates and cholesterol that made up one functional structure, the cell membrane
Fluid mosaic model
the major components
Phospholipid
proteins
cholesterol
carbohydrates
acts as a barrier to protect the cell against various environmental insults and more importantly, enables multiple cellular processes to occur in subcellular compartments
Phospholipids
Consists of glycerol, 2 fatty acid, phosphate-liked head group
Phospholipids
lipid-bilayer sphere
liposome
lipid-monolayer sphere
Micelle
which part in phospholipid forms with H+ bond w/ water and other polar molecules
Hydrophilic
helps cells to communicate, maintain their shape, carry out changes triggered by chemical messengers, and transport and share material
Protein
Protein base in location
Integral & peripheral
50% of the plasma membrane
proteins
[PROTEIN]
ALSO KNOWN AS INTRINSIC PROTEIN
Extends across lipid bilayer
Across cell membrane
Moves w/ help of detergent
Integral
Surface only
easily removed
composed of hydrophilic regions
Anchored on the exterior or interior only, does not extend across
Peripheral
Integral has
hydrophobic
Peripheral has
hydrophilic
penetrate the hydrophobic inside of lipid bilayer
Integral Proteins
most are transmembrane proteins
Integral Proteins
appendages loosely bound to either surface
Peripheral proteins
Protein base in function
Ion Channel
Carrier Proteins (transporters)
Enzymes
Receptor proteins
Recognition Sites
Pore that is so small that permits only few and specific ions (Na+, K+, Cl-, Ca2+)
are a very narrow tube-shaped protein that help establish a tiny pore in the cell membrane
Ion Channel
Permits entry and exit or large molecules (Glucose, Amino acid)
Will undergo changes
Carrier Proteins (transporters)
It speeds up the chemical reaction
Enzymes
Attachment of specific hormones
Use for communication
Binding sites
Receptor proteins
Protein with carbohydrates
For Identification
Important in immune system
Recognition sites (Glycoprotein)
always on the outside surface and are different from receptor sites. These allows white blood cells to recognize your cells vs foreign cells.
Recognition sites (Glycoprotein)
reduces membrane fluidity at moderate temps by reducing phospholipid movement
at low temps it hinders solidification by disrupting the regular packing of phospholipids
Cholesterol
It maintains the fluidity of cell membrane
Enables the cell to be flexible in changes of temp
Located in between phospholipids
Cholesterol
They are always found on the exterior surface of cells and are bound either to proteins (forming glycoproteins) or to lipids (forming glycolipids)
Carbohydrates
