Question

Explain the structure and function of different types of RNA.

Answer 1

• mRNA (messenger RNA)-

1. single-stranded
2. carries a copy of instructions to carry out amino acid assembling &protein synthesis
3. unstable
4. 5% of total RNA
5. In Prokaryotes – it is (polycistronic carrying coding sequence for many polypeptides
6. Eukaryotes – (monocistronic) contain information for only one polypeptide.
   
   Messenger RNA (mRNA)

• tRNA (transfer RNA)-

1. single-stranded clover-shaped with 4 arms highly folded -3 D structure
2. translates the code from mRNA and transfers amino acid to ribosomes (to built proteins)
3. unstable (also known as soluble RNA)
4. 15% of total RNA.
   
   Transfer RNA (tRNA)

• rRNA (ribosomal RNA)-

1. single-stranded
2. make up the 2 subunits of ribosomes
3. metabolically stable
4. 80% total RNA
5. A polymer with varied length from 120 – 3000 nucleotides & give ribosomes their shape
6. Genes of rRNA employed for phylogenetic studies.
   
   Ribosomal RNA (rRNA)