Molecular Biology

The central dogma is the principle that genetic information flows from DNA into RNA and then into protein, and never back from protein into nucleic acid.

A codon is a sequence of three nucleotides in DNA or messenger RNA that stands for one amino acid or tells the ribosome to stop.

Complementary DNA is DNA built from an RNA template, usually messenger RNA, by the enzyme reverse transcriptase, giving a DNA copy of an expressed gene.

DNA is the double-stranded molecule that carries the genetic instructions of nearly all living things, written in a code of four bases: A, T, C and G.

DNA ligase is an enzyme that links two pieces of DNA end to end, making a phosphodiester bond that seals a break in the sugar-phosphate backbone.

DNA methylation is the addition of a small methyl group to DNA, usually on cytosine, which can switch a gene off without changing its sequence.

The structure of DNA: nucleotides, the sugar-phosphate backbone, base pairs and hydrogen bonds, antiparallel strands and the grooves.

How a cell makes a protein: a gene is transcribed into mRNA in the nucleus, processed and exported, then translated by a ribosome.

How a replication fork copies DNA: helicase opens the helix, primase lays primers, and DNA polymerase builds a leading and a lagging strand.

How PCR copies one stretch of DNA: heat the strands apart, cool so primers bind, let Taq build new strands, and repeat until the copies number billions.

Two strands of DNA wound round each other, held together by base pairs: twelve of them here, about one full turn of the double helix.

The jellyfish protein that glows green: a barrel of eleven beta strands around a chromophore it makes from three of its own amino acids.

The adaptor of protein synthesis: an L-shaped RNA of 76 nucleotides that reads a codon at one end and carries an amino acid at the other.

The first step in packing DNA into chromosomes: 147 base pairs of DNA wrapped almost twice round a core of eight histone proteins.

Investigates the causes of human disease and looks for better ways to diagnose, treat and prevent it, through lab and clinical research.

Studies DNA, RNA and proteins to find out how genes are controlled and how cells work, grow and go wrong in disease.

Studies the chemistry of life: the proteins, fats, sugars and nucleic acids in cells and the reactions that keep them working.

Uses living cells, enzymes and microbes to make useful products, from medicines and vaccines to cleaner fuels and hardier crops.

Helps people and families understand inherited conditions and genetic test results, and what those mean for their health and choices.

Studies how genes are passed on and how changes in DNA shape traits and disease, in people, animals, plants or microbes.

How much stock to dilute, or the final concentration or volume, with C₁V₁ = C₂V₂.

The reverse complement, complement or reverse of a DNA or RNA sequence, or DNA written as RNA, from bare letters or FASTA.

Translate DNA or RNA into protein in any of the six frames, with the standard or a mitochondrial or bacterial code, and get the protein's mass and pI.