Which of the following statements is true?
(a) The signal sequences on mitochondrial proteins are usually at the C-terminus.
(b) Most mitochondrial proteins are not imported from the cytosol but are synthesized inside the mitochondria.
(c) Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes.
(d) Mitochondrial proteins cross the membrane in their native, folded state.
Choice (c) is correct. The signal sequences on a protein destined for the mitochondria are on its N-terminus [choice (a)]. Although some mitochondrial proteins are synthesized inside the mitochondria from the mitochondrial genome, most mitochondrial proteins are encoded by genes in the nucleus and imported into the mitochondria after synthesis in the cytosol [choice (b)]. Mitochondrial proteins are unfolded as they enter the mitochondria through protein translocators[choice (d)].
You might also like to view...
At the yeast mating-type locus, the mating-type switch is initiated by introducing a double-strand break at the MAT locus. What would happen if the double-strand break were introduced at the HML? locus instead?
A. The information at MAT would change. B. The information at HML? would change. C. The information at HMLa would change. D. The information at HML? would stay the same. E. None of the choices given is correct.
The intermediate-disturbance hypothesis predicts that the most species rich communities would contain
A. both r- and K-selected species. B. high rates of evapotranspiration. C. predominantly K-selected species. D. intermediate biomass. E. predominantly r-selected species.
What makes bdelloid rotifers so unique?
a. They reproduce sexually. b. They can reproduce sexually or asexually. c. They are all males. d. They can import DNA from other major kingdoms. e. A female can become a male if males are scarce.
What role does the corpus luteum play in maintaining the endometrium?
What will be an ideal response?