Level of life
DNA
The molecule that stores the genetic instructions of all cellular life: two strands wound into a double helix and held together by base pairs.
Molecular Biology
How DNA, RNA and proteins store and use life's instructions.
Molecular biology looks at the tiny molecules inside cells, especially DNA, RNA and proteins, to understand how living things work.
Molecular biologists study how genetic information is stored in DNA, copied, transcribed into RNA and translated into proteins, and how cells control which genes are used.
The field connects sequence to function: replication, transcription, translation and gene regulation, studied with tools ranging from PCR and sequencing to structural biology and genome editing.
Big questions
- How does a cell read and copy its genome?
- How do cells decide which genes to switch on?
- How does a protein's sequence decide what it does?
Key ideas
Open any idea in the knowledge graph to see what it connects to, here and in other fields.
Level of life
Gene
A basic unit of heredity: a stretch of DNA with instructions for a product such as a protein or a functional RNA.
Level of life
RNA
A single-stranded relative of DNA. Messenger RNA carries a gene's instructions to ribosomes, and other RNAs help build proteins and control genes.
Molecule
Messenger RNA
A copy of a gene's instructions that carries them from DNA to the ribosomes, where proteins are made.
Process
Transcription
Copying the DNA sequence of a gene into RNA.
Process
Translation
Ribosomes read messenger RNA three bases at a time and join the matching amino acids into a protein.
Idea or model
Genetic code
The rules that match each three-base codon to an amino acid or a stop signal. Nearly all living things share the same code.
Idea or model
Central dogma
Crick's principle that sequence information passes from nucleic acids to proteins and cannot pass from protein back to nucleic acid.
Process
DNA replication
Copying DNA before a cell divides. Each new double helix keeps one original strand and gains one new strand.
Process
Gene expression
Using a gene's information to make its product. Cells switch genes on and off as conditions change.
Process
Base pairing
In DNA, A pairs with T and G pairs with C (RNA uses U instead of T). The matching lets each strand act as a template for the other.
Process
RNA interference
Double-stranded RNA silences genes whose sequence matches it.
Also in Molecular Biology
Explore it in the labs
Simulation
Pair bases, follow a real human gene from DNA to protein, make mutations, and predict inheritance with Punnett squares.
- Genetics
- Molecular Biology
- Biochemistry
Interactive explorer
Tour an animal or plant cell: what each organelle does, the molecules inside it, related conditions and current research.
- Cell Biology
- Molecular Biology
- Biochemistry
Timeline and explorer
A sourced timeline from the double helix to CRISPR therapies, eight technologies labeled established or emerging, and a PCR model.
- Biotechnology
- Synthetic Biology
- Genetics
Current research
Search published papers and preprints in Molecular Biology, with clear labels for reviews, primary research, clinical trials and preprints.
Search papers in Molecular BiologySources & further reading
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
Molecular Biology of the Cell (4th edition) (opens the original in a new tab)
Alberts B, Johnson A, Lewis J, et al. (2002). Garland Science.
Free to read on NCBI Bookshelf. Standard reference for cell structure and molecular biology.
TextbookEducationalCentral dogma of molecular biology (opens the original in a new tab)
Crick F (1970). Nature 227:561-563.
Crick's own statement of what the central dogma does and does not claim.
Historical paperPerspectiveBiology 2e (opens the original in a new tab)
OpenStax (2018). OpenStax, Rice University.
Free introductory college textbook.
TextbookEducationalLicence: CC BY-NC-SA 4.0 (linked, not reused)
Deoxyribonucleic Acid (DNA) Fact Sheet (opens the original in a new tab)
National Human Genome Research Institute. genome.gov. National Human Genome Research Institute, NIH.
Fact sheetGovernment sourceWhat is DNA? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalMolecular structure of nucleic acids; a structure for deoxyribose nucleic acid (opens the original in a new tab)
Watson JD, Crick FH (1953). Nature 171(4356):737-738.
Proposed the double-helix model of DNA.
Historical paperPrimary researchWhat is a gene? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalMessenger RNA (mRNA) (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalHow do genes direct the production of proteins? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalPotent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans (opens the original in a new tab)
Fire A, Xu S, Montgomery MK, et al. (1998). Nature 391:806-811.
Discovery of RNA interference.
Peer-reviewedPrimary researchTranscription (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalTranslation (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducational
Show 7 more sourcesHide 7 sources
Codon (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalThe dependence of cell-free protein synthesis in E. coli upon naturally occurring or synthetic polyribonucleotides (opens the original in a new tab)
Nirenberg MW, Matthaei JH (1961). Proceedings of the National Academy of Sciences 47:1588-1602.
First codon assignment: poly-U RNA directs synthesis of polyphenylalanine.
Historical paperPrimary researchGeneral nature of the genetic code for proteins (opens the original in a new tab)
Crick FH, Barnett L, Brenner S, et al. (1961). Nature 192:1227-1232.
Frameshift experiments indicating the code is read in non-overlapping triplets.
Historical paperPrimary researchThe replication of DNA in Escherichia coli (opens the original in a new tab)
Meselson M, Stahl FW (1958). Proceedings of the National Academy of Sciences 44:671-682.
Showed that DNA replication is semiconservative.
Historical paperPrimary researchGene Expression (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalGenetic regulatory mechanisms in the synthesis of proteins (opens the original in a new tab)
Jacob F, Monod J (1961). Journal of Molecular Biology 3:318-356.
The lac operon model of gene regulation.
Historical paperPrimary researchBase Pair (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducational