Question

How does the ribosome know which proteins to make and how to make them?

Answer 1

Step-by-step explanation:

Ribosome is a complex containing ribosomal RNA (rRNA) and other enzymes/proteins. It is the site of protein synthesis which can be found either free-floating or attached to the endoplasmic reticulum in a cell. The second process of protein synthesis called translation, which is when instructions in mRNA is used to synthesize proteins, occurs in the ribosome.

Translation in the ribosome cannot occur without Transfer RNA (tRNA) which is a special type of RNA molecule that matches mRNA codon with its corresponding amino acid. Each tRNA contains a set of three nucleotides called ANTICODON, which it uses to read the mRNA codon (produced by transcription process) and then carries amino acid, specifically the one coded for by the protein it reads, and adds to the growing polypeptide (future protein).

Note that, the tRNA knows which amino acid to carry and add by reading the mRNA codon using its anticodon following the base pairing rule i.e. A-U, G-C

Hence, the ribosome produces a protein based on the amino acid sequence, each carried by tRNA.

The protein is finally released when the a stop codon is encountered in the ribosome, signalling the end of translation.

Answer 2

Ribosome knows which proteins to make depending on its location in the cell. For example if the ribosome is floating freely throughout the cell, it will make proteins that will be utilized within the cell itself. When attached to endoplasmic reticulum, it will produce proteins for the rough endoplasmic reticulum which are used inside the cell or outside the cell.