Chapter 7 Functions of membranes, fluid mosaic model Flashcards
What is the structural & function of the boundary of the cell?
The membranes provide a structural framework or anchor site for many enzyme, biochemical rxns, & and pathways, membranes play a important role in the biochemistry of living organisms
What are the organelles of the membrane?
receptors
what is the thing that is separating “what’s in” from “what’s out”?
The membrane
what is selective permeability?
The regulation which substrates can pass through the membrane and what cannot.
What biochemical role does membranes play in living organisms?
To have a structural framework or anchor site for many enzymes, biochemical rxns and pathways.
What is the point of receptors and other structures on the membrane surface?
to receive information signals from the surrounding environment.
What did Charles Overton discover?
That membranes are basically a lipid substance
What did Longmuir state?
That lipids are phospholipids
What did Gortner and Grendel discover?
That phospholipids form a lipid bilayer, that there are hydrophilic “polar heads” on the outside and non-polar hydrophobic tails on the inside.
What did Davson and Danielli find?
That membranes contain proteins “protein sandwich made” which are just proteins on the outside on both sides of the bilayer.
What did Robertson discover about cell membranes?
The “unit membrane” - are membrane function as a inseparable unit, meaning membranes cannot be partial and still be functional
What did Singer and Nicholson create?
The fluid mosaic model
What is the two dimensional fluids of membranes composed of?
A lipid bilayer - “fluid”, proteins embedded in the lipid bilayer like pieces of mosaic, lipids and proteins that flow laterally, 2 membranes that are asymmetric - that the two monolayers are composed of diffferent lipids and proteins, and there are two faces.
What are the two faces?
exoplasmic face (E-Face) - which faces “outside”, and protoplasmic face (p-face) - is the cytoplasmic face (c-face) faces inside
How do lipids and proteins flow?
They flow laterally
What is the characteristic of the 2 membranes? And what are they composed of?
They are asymmetric, the two monolayers are composed of different lipids and proteins.
What is the lipid bilayer composed of?
It is composed of two monolayers “leaflet” that have hydrophilic polar heads and hydrophobic polar tails.
What is Hydrophobic force?
It is what holds the bilayer together
What is a phospholipid composed of?
a hydrophilic head and a hydrophobic tail
What consists of the peripheral proteins?
a lipid anchored membrane protein that is covalently bonded, and one that is noncovalent.
What are integral proteins and what does it consist of?
They are proteins that are partially or all the way through the bilayer, they consist of monotopic proteins that stay in one monolayer, and trans-membrane proteins which go all the way through the bilayer
What are the different types of transmembrane proteins?
They are transport proteins, channel proteins, and carrier proteins
What is a channel protein?
they are proteins that are able to move small inorganic molecules or ions by facilitated diffusion
What are the transport proteins?
They facilitate passage of chemicals through the membrane
What is Uniport?
It is the movement of one molecule in one direction through the bilayer using facilitated diffusion.
What does symport do?
The movement of 2 molecules in the same direction one is passively by facilitated diffusion and the other is by piggy back.
What does antiport?
It is the movement of 2 molecules in opposite directions one is passively by facilitated diffusion, but it generates energy that then drives the other by active transport.
What does the transport ATPase pump do?
It uses ATP hydrolysis to move a molecule through the transport protein
What is the aspect that is in the monolayer that is found only in a animal cell? what is its characteristic?
Cholesterol, the characteristic is its fluidity
What type of things go through the transport proteins? what are the type of channel proteins for them?
Molecules and Ions, for molecules there are porins and aquaporins, and for ions they are ion channels
What are carrier proteins?
Also known as transport permease, they move large organic molecules by various mechanisms such as passive facilitated diffusion or by active transport, except never by ATP hydrolysis.
What is produced when ATP + H2O? and what catalyzes it?
ADP + Pi and ATPase catalyzes it
