Central dogma of molecular biology template

Replication, transcription and translation with their enzymes, the special transfers (reverse transcription, RNA replication), and the directions: templates read 3′→5′, new chains made 5′→3′, codons read 5′→3′ and proteins made N→C.

What the template shows

• DNA → RNA → protein: the enzymes for each transfer and the 5′→3′ rule for every nucleic acid chain
• Transfers of sequence information
• Solid: general transfers in every cell. Dashed: special transfers (viruses)
• mRNA (and tRNA, rRNA)
• DNA polymerases (III in E. coli; δ, ε in eukaryotes)
• RNA polymerase (Pol II for mRNA)
• ribosome, aminoacyl-tRNAs
• reverse transcription (retroviruses)
• RNA replication (RNA viruses)
• no transfer out of protein
• Antiparallel pairing: every new chain is made 5′→3′ against a template read 3′→5′
• new strand 5′→3′
• template (parent) strand, read 3′→5′
• new DNA strand: dNTPs add to the 3′-OH
• RNA made 5′→3′
• template (antisense) strand, read 3′→5′
• mRNA: same sequence as the coding strand (U for T)
• codons read 5′→3′
• mRNA: AUG (start) … UAA, UAG or UGA (stop)
• ribosome moves 5′→3′
• polypeptide grows N-terminus → C-terminus
• Crick (1958, restated 1970): sequence information can pass between nucleic acids and from nucleic acid to protein, but never out of protein.
• All polymerases add nucleotides to a free 3′-OH; DNA polymerases also need a primer (made by primase), so the lagging strand is built in Okazaki fragments joined by DNA ligase.
• The ribosome reads mRNA codons 5′→3′ and its peptidyl transferase (the 23S/28S rRNA, a ribozyme) builds the chain from the N-terminus to the C-terminus.

Drawn with 58 shapes – every one editable in MolDraw.

Sources

• Nelson & Cox, Lehninger Principles of Biochemistry, 8th ed., 2021, ch. 25–27 Textbook
• Berg, Tymoczko, Gatto & Stryer, Biochemistry, 9th ed., 2019 Textbook
• Crick, Symp. Soc. Exp. Biol. 1958, 12, 138 Original paper
• Crick, Nature 1970, 227, 561 Original paper
• Watson & Crick, Nature 1953, 171, 737 Original paper