Short answer
A chromosome is a packaged DNA molecule carrying many genes. A genome is the full set of genetic material in an organism or cell. Human nuclear DNA is arranged in chromosomes, while mitochondrial DNA is part of the human genome too. 1 2
A chromosome is one organized DNA unit; the genome is the complete genetic set to which chromosomes belong.
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At a glance
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| Question | Chromosome | Genome |
|---|---|---|
| Scale | One DNA package | Complete genetic set |
| Number in typical human body cell | Many chromosomes | One genome represented by those DNA molecules |
| Includes organelle DNA? | A nuclear chromosome does not | Usually yes when defining total cellular genome |
The table summarizes the cited definitions and the article’s stated scope. 1 2
What each thing is
Chromosome. A long DNA molecule packaged with proteins and carrying many genetic sequences. 1
Genome. The complete set of an organism’s genetic material, including all of its chromosomes and other genomic DNA. 2
Key differences
A genome is not one giant chromosome. In humans, nuclear chromosomes hold most DNA, but mitochondria have their own genome. Different organisms organize genomes differently; bacteria often have a main chromosome plus plasmids. 1 2
How to tell them apart
When discussing a numbered or named DNA structure, such as chromosome 21, use chromosome. When discussing all inherited DNA or a whole sequencing project, use genome. 1 2
Where they overlap
Chromosomes are major components of genomes. Both may include genes and noncoding sequences, and both can be sequenced. 1 2
Edge cases
A “haploid genome” means one representative set of chromosomes; a diploid cell carries two nuclear sets. Viral genomes and bacterial plasmids complicate a simplistic chromosome-count definition. 1 2
Why the distinction exists
The terms separate a physical packaging unit from the total information inventory needed to study inheritance and function. 1 2
Common misconceptions
Genome is not a synonym for “all genes.” It includes noncoding DNA, and chromosomes contain more than genes. 1 2
Examples
Chromosome 7 is one human chromosome. The human genome includes chromosome 7 together with the other nuclear chromosomes and mitochondrial DNA. 1 2
Sources
Sources checked October 3, 2026.
- National Human Genome Research Institute — Chromosomes Fact Sheet. Chromosome structure.
- National Human Genome Research Institute — Genome. Definition.