What are the roles of the DNA, RNA Polymerase, mRNA, tRNA and ribosome in protein synthesis

mRNA molecules carry the coding sequences for protein synthesis and are called transcripts. rRNA molecules form the core of a cell's ribosomes, the structures in which protein synthesis takes place. tRNA molecules carry amino acids to the ribosomes during protein synthesis. In eukaryotic cells, each class of RNA has its own polymerase, whereas in prokaryotic cells, a single RNA polymerase synthesizes the different class of RNA. Other types of RNA also exist but are not as well understood, although they appear to play regulatory roles in gene expression and also be involved in protection against invading viruses.

Explanation:

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times