A bacterium, an oak tree and a person all keep their instructions in DNA, written with four letters: A, T, G and C. A gene is a stretch of DNA that holds the recipe for one product, usually a protein. Established: Replicated many times; textbook knowledge.
Cells first copy a gene into a working message, mRNA (transcription). A ribosome then reads the mRNA and joins amino acids in the order it spells (translation), and the chain folds into a protein that does a job. This flow, DNA → RNA → protein, is the central dogma (Crick 1970). Which genes a cell copies, and when, is what makes a leaf cell different from a root cell, or a nerve cell from a skin cell.
Read: translation. A ribosome reads the mRNA three letters at a time. Each three-letter word adds one amino acid to a growing chain, which then folds into a working protein.
DNA double helix
Rotate with a finger or mouse. On a phone you can place it in your room (AR).
B-DNA dodecamer, PDB 1BNA (Drew et al. 1981, PNAS). Model: khushisingh.in, CC BY 4.0.
In my research: How gene expression is controlled in early development →
Sources
- Crick F (1970) Central dogma of molecular biology. Nature 227:561–563. doi:10.1038/227561a0
- Alberts B, et al. (2002) Molecular Biology of the Cell, 4th edition. Garland Science. Free on the NCBI Bookshelf. link