# Gene

A short section of DNA that holds the instructions for making one protein.

Biology (school) · Part 05: Genes and inheritance · Card 2 of 11 · Last updated 2026-10-19

## Analogy

One recipe in the book.

## In practice

A gene for making the protein insulin is found in the DNA of your pancreas cells.

## Practice

### Flashcards

- **What is a gene?** A section of DNA that codes for one protein.

## Questions people ask

### How does a gene make a protein?

A copy of the gene is made and travels out of the nucleus to a ribosome. The order of the bases in the gene decides the order of amino acids the ribosome joins together. The chain folds into a protein. Different genes make different proteins with different jobs.

### How many genes do humans have?

Humans have roughly 20,000 genes that code for proteins. Many genes are shared with other animals, which helps scientists study disease in mice or fruit flies. Genes make up only a small part of our DNA. The rest has other jobs, such as controlling when genes switch on.

## Related concepts

- [DNA](https://studyvisually.com/learn/science/biology-school/biology-school-part-5/biology-school-part-5-concept-1)
- [Chromosome](https://studyvisually.com/learn/science/biology-school/biology-school-part-5/biology-school-part-5-concept-3)
- [Allele](https://studyvisually.com/learn/science/biology-school/biology-school-part-5/biology-school-part-5-concept-4)

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