Like DNA, RNA is a polymer of nucleotides. In an RNA nucleotide, the sugar ribose is attached to a phosphate molecule and to a base, either G, U, A, or C. Notice that in RNA, the base uracil replaces thymine as one of the pyrimidine bases. RNA is single-stranded, whereas DNA is double-stranded.
Small nuclear ribonucleic acid (snRNA) is a class of small RNA molecules that are found within the nucleus of eukaryotic cells. They are transcribed by RNA polymerase II or RNA polymerase III and are involved in a variety of important processes such as RNA splicing (removal of introns from hnRNA ), regulation of transcription factors ( 7SK RNA ) or RNA polymerase II (B2 RNA), and maintaining the telomeres . They are always associated with specific proteins, and the complexes are referred to as small nuclear ribonucleoproteins (snRNP) or sometimes as snurps. These elements are rich in uridine content. A large group of snRNAs are known as small nucleolar RNAs (snoRNAs). These are small RNA molecules that play an essential role in RNA biogenesis and guide chemical modifications of ribosomal RNAs (rRNAs) and other RNA genes (tRNA and snRNAs). They are located in the nucleolus and the Cajal bodies of eukaryotic cells (the major sites of RNA synthesis).
Transcription occurs when DNA acts as a template for mRNA synthesis. Translation occurs when the sequence of the mRNA codons determines the sequence of amino acids in a protein.
The end products of protein synthesis is a primary structure of a protein
A sequence of amino acid bonded together by peptide bonds
aa1 aa2 aa3 aa4 aa5 aa200 aa199
Messenger RNA (mRNA) methionine glycine serine isoleucine glycine alanine stop codon protein A U G G G C U C C A U C G G C G C A U A A mRNA start codon Primary structure of a protein aa1 aa2 aa3 aa4 aa5 aa6 peptide bonds codon 2 codon 3 codon 4 codon 5 codon 6 codon 7 codon 1