Means Of Transport:facilitated Diffusion Flashcards
A … must already be present for diffusion to
occur.
Gradient
The diffusion rate depends on the …
Size of the substances
….size of substances diffuse faster.
Smaller
The diffusion of any substance across a
membrane also depends on …
its solubility in lipids.
…Is the major constituent of
the membrane.
Lipid
Substances soluble in lipids diffuse through the membrane
….
Faster
Substances that have a …find it difficult to pass
through the membrane.
hydrophilic moiety
movement of…has to be facilitated.
Hydrophobic substances
… provide sites at which such molecules cross the membrane.
Membrane
proteins
Facilitated diffusion definition?
Hydrophobic substances do not set up a concentration gradient: a concentration gradient must
already be present for molecules to diffuse even if facilitated by the proteins.
This process is called facilitated diffusion.
In facilitated transport …. do not set a…
Membrane proteins
Conc. Gradient
Conc. Gradient should already present in …in facilitated diffusion
Membrane
In facilitated diffusion … help move substances across
membranes without expenditure of …
special proteins
ATP energy.
Facilitated diffusion
cannot cause net transport of molecules from a …
low to a high concentration
In facilitated diffusion, how molecules are transported from low to high conc. gradient?
By input of energy
Transport rate reaches a maximum
when ..
all of the protein transporters are being used (saturation).
All of the protein transporters are being used results…
Saturation
Which diffusion is very specific?
Facilitated
Facilitated diffusion is very specific because..
allows cell to
select substances for uptake
…. sensitive to inhibitors
Facilitated diffusion
inhibitors react with
…
protein side chains
The proteins form channels in the
membrane for…
molecules to pass through.
Some channels are always …; others
can be controlled.
Open
Channels of diffusion can be controlled or not?
Controlled
The porins definition
proteins that form huge
pores in the outer membranes of the plastids, mitochondria and some bacteria allowing molecules up to the size of small proteins to pass through.
Poring for large pores so that…
molecules up to the size of small
proteins can pass through
Porins are….
Proteins
Porins are formed in the…membrane
Outer
Porins are formed in…
1.plastids
2.mitochondria
3.some bacteria
an extracellular molecule bound to the transport protein; the transport protein then rotates and releases the molecule inside the cell, in …
Water channels
Water channels are made up of …
8 different types of aquaporins
