Many proteins of the chloroplast are encoded by genes in the nucleus. In these cases the RNA is transcribed in the nucleus, translated by the cytoplasmic ribosomes and the protein transported to the chloroplast. For such a protein how many membrane(s) does the protein cross to reach the thylakoid space (lumen) of the chloroplast?
(a) One
(b) Two
(c) Three
(d) Four
