Question

Which statement about ribosomes is correct?


Prokaryotic ribosomes are larger than eukaryotic ribosomes.




Prokaryotic ribosomes are smaller than eukaryotic ribosomes.




Prokaryotic and eukaryotic ribosomes are same in size.

Answer 1

Prokaryotic Ribosomes
Generally prokaryotic ribosomes are called 70S ribosomes, which are smaller than eukaryotic ribosomes (Taylor, 1998). Ribosomes consist of two subunits, and these two subunits are called 30S and 50S, the smaller unit and the larger unit respectively. These ribosomes units are denoted by Svedberg (S) values depending on the rate of the sedimentation in the centrifugation . In prokaryotes, rRNA is organized into three strands in ribosomes .


Eukaryotic Ribosomes
Smaller subunit and larger subunit of eukaryotic ribosomes are described as 40S and 60S respectively, and the whole ribosome is 80S. This is lager than the prokaryotic ribosome. The rRNA in ribosomes has four strands. Ribosomes are produced in the nucleolus, in a special position in nucleus.


What is the difference between Eukaryotic and Prokaryotic Ribosomes?
• Prokaryotic ribosomes are smaller (70S) than eukaryotic ribosomes (80S).
• Prokaryotic ribosomes consist of 30S and 50S, the smaller unit and the larger unit respectively whereas eukaryotic ribosomes have smaller subunit and larger subunit as 40S and 60S respectively.
• In eukaryotes, rRNA in ribosomes has four strands whereas, in prokaryotes, rRNA is organized into three strands in ribosomes .
• In eukaryotic cells, ribosomes are in free and bound form, whereas prokaryotic cells have only free form.
• Eukaryotic cells have chloroplasts and mitochondria as organelles and those organelles also have ribosomes 70S. Therefore, eukaryotic cells have different types of ribosomes (70S and 80S), whereas prokaryotic cells only have 70S ribosomes.
• Eukaryotic ribosome consists of eight kinds of protein and five kinds of rRNA, and prokaryotic ribosomes are made of three types of rRNA and fifty kinds of protein.


source : http://www.differencebetween.com/difference-between-prokaryotic-and-vs-eukaryotic-ribosomes/