Complexity of you
How many letters does it take to spell you?
- as many letters as parts in — Boeing 747s
- — years to read aloud, one letter a second, nonstop
- as many letters as — King James Bibles
In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through him, and without him was not any thing made that was made.
John 1:1–3 (ESV)
In the beginning, you were a word. A unique 3.1B-letter word. Spoken by God, created in his image.
The machine that builds every protein: a human ribosome
One ribosome is built from — proteins and — RNA strands: — amino acids, — RNA bases and — atoms (not counting hydrogen), held together with — metal ions. It is about — nanometers across, and a growing human cell has millions of them.
One dot per amino acid (protein) or RNA base, from the cryo-electron microscopy structure PDB 4UG0 (see References). Drag to turn it; point at a dot to see which molecule it belongs to. Flexible parts that the microscope could not resolve are missing, so the real ribosome is somewhat larger.
How a gene becomes a protein: insulin
The real sequence of the human insulin gene (INS), drawn base by base. Shapes are simplified and both steps run roughly 10 to 20 times slower than in a cell, where RNA polymerase adds about 30 to 60 bases a second and a ribosome about 5 amino acids a second. Scroll sideways on a small screen.
References
Cell types per system count each distinct type found in that system's tissues. Many types, such as fibroblasts and endothelial cells, appear in several systems, so the rows add up to more than the total. The three machines are real human structures from the Protein Data Bank, one dot per amino acid (listed below). What they are doing is a simplified sketch, slowed down a great deal: a real pump runs dozens of cycles a second, and ATP synthase spins more than 100 turns a second.
- The human cell count and size distributionHatton et al., PNAS, 2023 (free copy at NIH PubMed Central); cell types per organ system, from the reference adult male (1,264 cell groups in 60 tissues)
- Reviewed human proteins (Swiss-Prot)UniProt; 42,562 proteins counting variant forms (queried October 2026), and the 20,431 canonical proteins behind the codon count
- The Human Protein AtlasHuman Protein Atlas; 20,162 protein-coding genes
- The standard genetic codeNCBI; 64 codons, 61 for amino acids and 3 for stop
- T2T-CHM13v2.0, the complete human genomeNCBI; one copy of each chromosome, X and Y included
- Human CMG helicase bound to DNA (PDB 6XTX)Rzechorzek et al., Nucleic Acids Research, 2020; RCSB Protein Data Bank
- Human sodium-potassium pump (PDB 7E1Z)Guo et al., Nature Communications, 2022; RCSB Protein Data Bank
- Human ATP synthase (PDB 8H9S)Lai et al., Molecular Cell, 2023; RCSB Protein Data Bank
- Human 80S ribosome (PDB 4UG0)Khatter et al., Nature, 2015; RCSB Protein Data Bank
- Human insulin gene, INS (NM_000207.3)NCBI RefSeq; the sequence in the insulin animation
How the numbers were counted: each tissue in the cell-count study is assigned to one of the 11 systems (eyes and ears with nervous; teeth, tongue and salivary glands with digestive; larynx with respiratory; red bone marrow with lymphatic and immune; adipose tissue with integumentary; breast with reproductive). Endocrine covers only the adrenal and thyroid glands the study lists; pancreatic islet cells count under digestive. Variant forms are the different proteins one gene can make by splicing its message differently. "Codons in all" counts one codon per amino acid plus one stop codon for each canonical protein, and DNA bases are three per codon, the protein-coding part only. Each cell carries two copies of the genome, about 6.2 billion bases; the older reference, GRCh38, is 3.10 billion bases with gaps. Reading aloud assumes one letter a second around the clock.