Transport of substances through cell membranes Flashcards
Which substances can diffuse through the cell membranes?
Lipid-soluable substances
2 types of transport through th e cell membrane
Diffusion
Active transport
2 types of diffusion
Simple
Facilitated
What does water diffuse through in the cell membrane?
Acquaporins
What does tubular pathways do?
Allow substance to move via simple diffusion from one side to the other
When are pores open?
Always
What creates selective permeability via gating of channels?
Tubular pathways
2 features of protein channels
Selectively permeable
Gated
What are selectivity filters line say?
Amino acid residues (negative charges)
What are gated protein channels controlled by? (2)
Voltage gating
Chemical (ligand) gating
What is an electrical current?
When ions ar removed from one point to another
Different name for facilitated diffusion
Carrier mediated diffusion
What is the rate of simple diffusion directly proportional with?
Concentration of the diffusing substances
Are the gated channels always open?
No
What is the rate of inward diffusion proportional to?
Concentration of molecules on the outside of the cell