membranes Flashcards
is lipids and water non polar or polar?
lipids are no polar and water is polar
what is a micelle?
a spherical arrangement of phospholipids
hydrolysis meaning?
breaking something down using water
what is a condensation reaction?
when a bond is formed that is a condensation reaction
how are phospholipid bilayers formed?
formed when they are placed in an aqueous environment
what are transmembrane’s?
transmembrane’s are proteins only within the phospholipid bilayer. they are within which is integral. there are proteins are attached which is peripheral.
they can also be permanent or temporary
gated transmembrane channels allow selected molecules through depending on conditions within the cell which determine whether they open or close.
there transmembrane Chanels allow substances to pass through in both directions. some are active carrier systems which use energy to transport.
what are the functions of transmembrane’s (proteins)?
allow for transport of substances that are not able to go through phospholipid membranes/ bilayer themselves.
ionic, molecular and electron transport
what are glycoproteins ?
proteins which have carbohydrate groups attached to them. they allow cells to communicate with one another and are used for immunity.
proteins on the cell surface also act as receptors for incoming messages such as hormones. (proteins used for communication and transport)
describe and explain the fluid mosaic model of plasma membrane (cell membrane)?
phospholipid bilayer is not fixed structure/ not rigid/ flexible although the bilayer will always remain arranged in this configuration. Thus membranes can change shape for processes like phagocytosis. It also allows proteins to move latterly within he cell membrane.
fluid - specifically refers to the movement of phospholipids in the plane of the membrane
it is mosaic as it is made up of many macromolecules including glycoproteins, lipoproteins, cholesterol , transmembrane proteins and phospholipids.
mosaic refers to the random arrangement/ association of proteins different shapes and sixes within the membrane/ phospholipid bilayer
why is it important for cell membranes to have fluid mosaic model?
carry out function effectively
what Can affect fluidity of cell membrane ?
the ratio of saturated and unsaturated fatty acids determins fluidity. cholesterol helps the cell membrane remain correct fluidity. during warmer temperatures it provides structural support to prevent phospholipids from becoming too fluid. cholesterol enhances the permeability bilayer. more cholestrol makes the membrane stabalized and have a higher meltig point.
how many fatty acids are there in the fatty acid chain
two fatty acids in fatty acid chain which are hydrophobic
