Membrane Transport Flashcards
What is entropy
Entropy is something that always increases and it is the law that all particles go to disorder (everything wants to diffuse)
Why is membrane transport important
Because cells need nutrients which cannot pass through the membrane
What is flux
Number of molecules passing through an area in a given amount of time. The diffusion of molecules
What is the diffusion coeficcient
Other things that the flux cares about (size of the molecule and temperature)
What does the permeability mean
How easy it is to pass through (p=0 cannot go through, p=1 can go through super easliy)
What is needed to be permeable in membranes
Small and non polar molecules
Is flux and permeability the same thing
yes (in this context)
What is the dominant extracellular cation
Na+
What is the dominant intracellular cation
K+
What is the dominant extracellular anion
Cl-
What is the dominant Intracellular anion
PO4(3-)
What is an aquaporin
A small membrane transport machine which transports water
What is osmorality
The concentration of everything that dissolves in water other than water
How does entropy apply in water
Water diffuses to high osmorality
What is the osmolarity of 1mol/L aqueous solution of Na3PO4
4 osmolar
What is the osmolarity of cytoplasm
0.3 osmolar
Why do cells not like pure water
Difference in osmolarity causes extreme pressure in the cell (8atm for 0.3 osmolar difference)
What is tonicity
Whether a cell grows or shrinks due to osmosis
What is isotonic
No movement of water in and out of the cell
What is hypo and hyper tonic
Hyper - high pressure in the surroundings, cell compresses
Hypotonic - cell expands
Why is an iso-osmolar solution not always isotonic
Osmolarity is measured in the beginning, tonicity is measured at the end. One thing can not be in equilibrium making the solution not isotonic at the end.
What are the different types of transport activity
Diffusion
Channel
Transport
Active transport
What are the types of passive transport
Simple diffusion, channel mediated (with a channel protein)
how does active transport work?
Through a transportation pump.
What are the types of gates for channel proteins
Voltage gated, ligand gated and mechanically gated
What cell gates do the laws of linear flux apply to
Simple diffusion, channel diffusion
Why does carrier mediated diffusion have a rate limit
Because it can only move a specific speed (saturate)
Why are carriers used
because if there is a low concentration gradient, it can achieve a higher rate than standard diffusion
Why do we need to eat both salt and sugar
Salt has sodium, which is necessary to get a strong concentration gradient. This means that the body can scavenge for sugar into the cell.
Which conc gradient is used for if two chemicals want to go in for a transporter
The strongest
What are the different types of active transport
P type (ions), F type (produce ATP), ABC transporter (molecules)
Do ABC transports go in both directions
no
How many ions does one ATP-ADP reaction fuel
2K+ goes in, 3NA+ goes out
Which fluid is negatively charged
intracellular fluid
How does glucose and sodium transport work
The glucose and sodium goes in the cell via transporters. Then the glucose pumps with the blood with concentration gradient via passive transporters and the NA gets pumped out with the counteraction of K+ with P type pump
How does exocytosis work
When a hormone arrives, the membrane will let it out
How does random endocytosis work
Cell bumps into something, then forms a vesicle.
