In a plant cell, ribosomes are found attached to the rough endoplasmic reticulum and also inside the stroma of the chloroplast. What are the sedimentation coefficients of the smaller subunits of the ribosomes found in these two locations, respectively?

Step-by-step solution

Ribosomes attached to the rough endoplasmic reticulum (cytoplasmic ribosomes) in eukaryotes are of the 80S type. The 80S ribosome consists of a larger 60S subunit and a smaller 40S subunit. Ribosomes found inside the stroma of the chloroplast are smaller and are of the 70S type. The 70S ribosome consists of a larger 50S subunit and a smaller 30S subunit. Therefore, the sedimentation coefficients of the smaller subunits for the rough ER and the chloroplast stroma are 40S and 30S, respectively. Answer: 40S and 30S