Question

Ribosomes are essential for protein synthesis, but they are present in mitochondria and plastids, the sites of respiration and photosynthesis. What is the role of ribosomes in these organelles?
A. Ribosomes transport ATP formed in respiration and photosynthesis to cytoplasm through ER
B. Subunits of some required proteins are synthesised in these organelles
C. Ribosomes transport RNA and DNA to cytoplasm
D. All of these

Answer 1

Correct Answer - B
Ribosomes are found inside the chloroplast and mitochondria, besides nucleus. It is mainly, these organelles are semiautonomous, i.e., some of the proteins that are utilised for organelle functioning are synthesised in these organelles as well as in nucleus, e.g. large subunit of RuBisCO is synthesised in chloroplast while small in nucleus.