Question

Explain the process of formation of complex proteins.

Answer 1

Proteins are synthesised through transcription, translation, and translocation according to the nucleotide sequence of DNA with the help of RNA. This process is called the central dogma of protein synthesis.

1. Transcription: During transcription, the two strands of DNA separate and one strand acts as a template for the formation of mRNA. The nucleotide sequence on mRNA is complementary to the DNA strand. In RNA, uracil replaces thymine. Transcription occurs in the nucleus, and the formed mRNA carries the genetic code to the cytoplasm. The genetic code is present in the form of triplet codons, each coding for a specific amino acid.
2. Translation: In translation, ribosomes read the codons on mRNA. Transfer RNA (tRNA) brings specific amino acids in response to codons. Each tRNA has an anticodon complementary to the codon on mRNA.
3. Translocation: During translocation, the ribosome moves along the mRNA one codon at a time. Ribosomal RNA (rRNA) helps join amino acids with peptide bonds to form polypeptide chains, which later fold into complex proteins.