Question

What are ribosomes composed of?

Answer 1

Ribosomes:

1. Ribosomes are macromolecular machinery that executes biological protein synthesis in all cells.
2. The primary function of ribosomes is to synthesize protein molecules.
3. These structures are found in both prokaryotes and eukaryotes.

Composition of ribosomes:

1. A ribosome is a ribonucleoprotein, which means it is made up of RNA and protein.
2. It is made up of two subunits, one smaller and the other larger.
3. In prokaryotes and eukaryotes, the densities of the ribosomes differ.

Prokaryotic ribosomes:

1. In prokaryotes, ribosomes are made up of two subunits with densities of the 50S and 30S.
2. The 30S subunit has a 16S rRNA with a length of 1540 nucleotides, whereas the 50S subunit has a 5S rRNA with a length of 120 nucleotides, and a 23S rRNA with a length of 2900 nucleotides.
3. During protein synthesis, the two subunits join to create a full 70S ribosome.

Eukaryotic ribosomes:

1. in eukaryotes, the ribosomal subunits possess the 60S and 40S subunits that together make up 80S ribosomes.
2. The 40S subunit in most eukaryotes contains an 18S rRNA with a length of 1900 nucleotides; the 60S subunit contains a 5S rRNA with a length of 120 nucleotides, a 5.8S rRNA with a length of 160 nucleotides, a 28S rRNA with a length of 4700 nucleotides.
3. During protein synthesis, the two subunits join to create a full 80S ribosome.