Biology Forums - Study Force

For example, if there were a higher concentration of proteins in the cystol than in the mitochondria, do these proteins (enzymes) diffuse into the mitochondria? (And does the same occur for a very high concentration of enzymes inside the mitochondria, with the proteins diffusing outwards?)

Proteins (to the best of my knowledge) are not lipid soluble. This did come up as a coursework question, so I'm wondering how this happens.

Hello again...


The mitochondrial membrane is not permeable to large molecules like proteins, even though there might be a concentration gradient.

I mean there are proteins on orgenelles which allow proteins to go in and out
So I'm wondering if too many proteins would cause them to diffuse out

True, membrane-bound organelles do have transport proteins, but these are designed for smaller molecules like water (aquaporins) and glucose (glucose transporter). No way would proteins diffuse - as far as I know.

yes im aware they cannot passively defuse.

but there are protein ''gates'' on the membrane of organelles which allow proteins to pass in and out

is this a form of diffusion? would the proteins pass out of an organelle through these gates if there was a higher concentration than other areas?

Not by definition, no. Proteins move in-and-out of a cell via exocytosis most often.

Proteins are degraded by proteosomes. If there is a problem marking proteins by ubiquitilyzation to be destroyed by the proteosomes then proteins may build up.