DNA and RNA

From a DNA or mRNA fragment: the complementary strand, transcription, tRNA anticodons, amino acids from the genetic code table, DNA length and mass.

Use the letters A, T, G, C, U; separators and the 5′ and 3′ end labels may stay. DNA has no uracil (U), RNA has no thymine (T). Up to 150 nucleotides.

Test yourself

The DNA and RNA calculator solves molecular biology problems: from a fragment of one strand it finds the second DNA strand, the mRNA, the tRNA anticodons and the amino acid sequence of the protein from the genetic code table. It also gives the length and mass of the DNA fragment, the GC content and the number of hydrogen bonds.

Base pairing

Process	Base pairs
DNA — DNA (replication)	A — T, G — C
DNA — mRNA (transcription)	A — U, T — A, G — C, C — G
mRNA — tRNA (translation)	A — U, G — C

The mRNA is built on the DNA template strand, so it matches the coding strand with uracil in place of thymine. Every three mRNA nucleotides (a codon) code for one amino acid; UAA, UAG and UGA are stop codons.

Example. DNA template TAC-GCA-TTG → mRNA AUG-CGU-AAC → tRNA anticodons UAC-GCA-UUG → protein Met-Arg-Asn.

Useful numbers

One nucleotide adds 0.34 nm to the strand, so the DNA length = number of base pairs · 0.34 nm.
The average mass of a nucleotide is 345 Da, of an amino acid 110 Da.
A and T are joined by two hydrogen bonds, G and C by three.

DNA strands are antiparallel. As usual in school problems, the calculator writes the complementary strand under the given one, left to right.