Membrane Structure Flashcards
organs definition
specialized structure in the body that perform specific life processes
organelles definition
specialized structures inside the cell that perform specific cellular processes
often surrounded by a membrane
cell fractionation
a method of separating cell parts to study their function
homogenization definition
the disruption of cell membrane without damaging organelle
centrifuge
instrument that spins a high speeds to spearate contents by density
4 ways to rupture the plasma membrane
- break cells with high frequency
- use a mild detergent
- use high pressure by forcing cells through a small hole
- shear cells between a close fitting rotating plunger
steps to cell fractionation
- homogenize
- centrifuge
- decant supernatant
- repeat centrifugation at higher speeds to separate into smaller components
pellet
larger, more dense components of tissue
supernatant
lighter suspended in liquid above the pellet in tissue
plasma membrane
aka cell membrane all cells and organelles are surrounded by it
what is the membrane composed of?
- phspholipids
- membrane proteins (integral, peripheral)
- carbohydrates
- cholesterol
what is each layer called in a phospholipid bilayer
leaflet
what environment is the phospholipid bilayer in?
water is on both sides -> cell is in water environment and the cell interior is also a water environment (polar)
how is the phospholipid arraged in the phospholipid bilayer
- hydrophobic tails face inward forming a hydrophobic core
- hydrophilic heads face outwards
what are the two locations classification of membrane proteins
integral, peripheral
what are the classification of integral proteins
- polytopic transmembrane, sinlge-pass, multi-pass
-monotopic
what are the classifications of peripheral proteins
- extracellular
- intracellular
what does polytopic mean?
faces both sides of membrane
transmembrane definition
spans entire phospholipid bilayer
single pass protein definition
crosses membrane once
multi-pass protein definition
crosses membrane several times
monotopic definition
associated with membrane on one side, does not span entire bilayer
how are non peripheral mombrane proteins bound?
non-covalently to either surface of the membrane
does NOT enter the leaflet
functions of membrane proteins
- receptor
- enzymatic activity
- recognition
- attachment
- transport
- cell adhesion
types of transmembrane proteins
- receptor protein
- channel protein
- gated channel protein
- transport protein
- glycroprotein protein
receptor protein
has a binding site to fit the molecule which acts as a chemical signal/messenger,
result of binding in receptor protein
causes a conformational change in receptor protein, which results in a relaying message to the interior of the cell
enzymatic activity
protein has a binding sit for molecule, binding results in a chemical reaction that changes the substrate to a new product
recognition protein
glycoprotein, surface carbohydrate groups help identifycell (eg antigens)
what does an attachment protein attach to?
interior cytoskeleton, exterior extacellular matrix (ECM)
what does the attachment protein do?
provide structural support
where does the extracellular cell face?
exterior/outside of the cell
what do extracellular proteins attach to?
the extracellular matrix, ECM
what is the fuction of ECM(extracellular matrix)
- supports cell structure
- anchors cell
- separates tissues
- functions in cell signalling