B2.1 membrane and membrane transport Flashcards
phospholipid bilayer
consists of phosphate and fatty acids
( hydrophilic polar head and hydrophobic non polar tail)
micelle
phospholipid bilayer shaped in a circle, wth hydrophobic area in the centre and membrane enclosed structures
libosome
circular membrane
enclosed structure
hydrophobic area and hydrophilic area
2 circles
amphiapathic properties
both polar and non polar properties in the same structure
why do phospholipids clump together
non polar regions clump together on the inside of the bilayer,polar regions (head) move towards the outside of the bilayer where they contact with water
fluid mosaic bilayer
flexible, resistant and ability to change shape
composition of many structural molecules embeded in the bilayer such: proteins carbs and cholesterol
structure of plasma cell membrane
1) phospholid bilayer
2) polar head and tail
3) cholesterol
4) carbohydrate group
5) glycolipid
6) integral transmembrane protein
7) integral protein
8) peripheral protein
9) glycoprotein
what does cholesterol do
regulates the fluidity of the membrane
what does glycolipid do
acts as cell receptors and/or recognition
what does integral transmembrane protein and integral protein do
function as channels pumps and enzymes
integral means permently associated with cell membrane
receptor protein
these membrane proteins recognize and respond to chemical signals from outside the cell. when the chemical signal binds, the membrane protein triggers a response by the cell
example of receptor protein
insulin receptor protein is a hormone released by the pancreas when blood sugar levels are high. inslulin binds to the isulin receptor protein, which then allows glucose to enter cell from blood
adhesive proteins
proteins that achor the cell membrane to:
the inner cytoskeleton
proteins outside the cell
other cells
examples of adhesive proteins
desmone proteins are found in muscles tissue where they bind muscle cells to one another
recognition protein
these membrane proteins serve as identification tags on the surface of the cell. these are often “glycoproteins” with the carbohydrate portion projecting out of the cell and into the extracellular space. these give the cell a biochemical personality and are important in cell-to-cell recognition
regocnision protein examples
imunoglobulins or antibodies b cells carry antibodies embeded by the tail in the outer cell membrane, with the binding sites facing outwards. this enables the b cells to bind to antigens
channel protein
these membrane allow small molecules to pass through the cell membrane by creating a pore through the membrane.
channel protein examples
proteins called aquaporin allows water molecules to move through the cell membrane single file
pump protein
.these proteins function to move small molecules or ions across the cell membrane by creating a pore through the membrane.
crate concentration gradient- energy from low to high
pump protein examples
the calcium pump allows muscles to relax after contraction y moving calcium ions back into th
