Question

Which of the following statements is TRUE?

a)the signal sequences on mitochondrial proteins are usually at the C-term
b)most mitochondrial proteins are not imported form the cytosol but are synthesized inside the mitochondria
c)chaperone proteins in the mit facilitate the movement of proteins across the outer and inner mit membranes
d)mit proteins cross the membrane in their native, folded state

Answer 1

The true statement about mitochondrial proteins is that chaperone proteins facilitate their translocation across mitochondrial membranes by assisting in their unfolding and refolding during the import process.

Step-by-step explanation:

The true statement concerning mitochondrial proteins is that chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes. Proteins synthesized in the cytosol destined for the mitochondria commonly have an N-terminal signal sequence that directs them to the organelle. On arrival at the mitochondrial surface, they bind to a receptor protein before being unfolded by chaperone proteins like HSP70. This unfolding allows the protein to cross the membrane, and subsequently, it is refolded inside the mitochondria to assume its biologically active form. The signal sequence is typically removed following import into the mitochondria.