Biochemistry in Tables, Schemes, and Graphs - S.D. Zhamsaranova 2009

Transmembrane Signal Transduction
RNA Synthesis: Transcription

METABOLISM/31.html">Transcription is the synthesis of RNA on a DNA template. The resulting primary transcripts of mRNA, tRNA, and rRNA are complementary to the template DNA strand (3',5'-strand).

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Ribonucleoside triphosphates (ATP, GTP, CTP, UTP) serve as substrates and Energy Sources for RNA synthesis.

RNA synthesis is catalyzed by RNA polymerase Enzymes.

Transcription involves three stages: initiation, elongation, and termination.

The region where RNA polymerase binds is called a promoter. Promoter activation is mediated by a protein factor (TATA factor). RNA polymerase, along with the growing RNA chain, moves along the template until it reaches a termination codon. In eukaryotic DNA, the information required for Protein Synthesis is stored in regions called exons, which are separated by introns—segments that contain no Genetic information (non-coding regions). During Gene transcription, a primary transcript is initially formed, which then undergoes Processing, known as maturation. This process involves excising introns (splicing) from the mRNA prior to Translation and attaching characteristic terminal sequences to the mRNA.

REMOVAL OF INTRONS FROM mRNA

PROTEIN SYNTHESIS – TRANSLATION OF GENETIC INFORMATION

The transmission of information is based on the biological code, which is the method of encoding the Amino Acid Sequence of Proteins using a sequence of NUCLEOTIDES in DNA or RNA.

Properties of the BIOLOGICAL CODE

Triplet code

The code word consists of 3 nucleotides. Three nucleotide residues (a triplet) encode a single amino acid. The termination triplets UAA, UAG, and UGA do not encode Amino Acids and serve as signals for the termination of protein synthesis

Specificity

Each triplet encodes only one specific amino acid

Degeneracy

A single amino acid can be encoded by multiple (from 2 to 6) triplets

Universality

The biological code is identical across all species of organisms

Colinearity

The sequence of codons in mature mRNA corresponds to the sequence of amino acids in the synthesized protein

Note. In mature mRNA, information is encoded as a linear sequence of codons (triplets) and is read in the 5' to 3' direction.

THE BIOLOGICAL CODE (CODON NUCLEOTIDE SEQUENCES ARE READ FROM THE CENTER TO THE PERIPHERY)



Last update: 06/08/2026

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