Cite the three main types of RNA and describe briefly the function of each.

mRNA: Carry genetic information from DNA to protein; serve as template for protein synthesis.

tRNA: Serves as adapter molecule and deliver specific amino acid from the cell pool to the mRNA-ribosome complex.

rRNA: Structural component of ribosomes.

Explanation:

There are three types of nongenetic RNAs: mRNA, tRNA, and rRNA.

1. The messenger RNA (mRNA) is formed by the process of transcription in the nucleus. Transcription uses template strand of DNA to specify the nucleotide sequence in mRNA. The mRNA enters cytoplasm to join ribosomes. The nucleotide sequence of mRNA serves as a template and specifies the amino acid sequence of proteins.

2. The transfer RNA (tRNA) serves as an adapter molecule during the process of protein synthesis and binds to the specific amino acids to deliver them to the protein-synthesizing machinery. The anticodon of tRNA binds to the complementary mRNA codons.

3. The ribosomal RNA (rRNA) serves as structural components for ribosomes. Each of the subunits of ribosomes is made up of rRNA and proteins.