General Knowledge
What is the longest human chromosome called?
- Chromosome 1
- Chromosome X
- Chromosome 23
The answer is Chromosome 1. The largest by base pairs.

Chromosome 1 is the designation for the largest human chromosome. Humans have two copies of chromosome 1, as they do with all of the autosomes, which are the non-sex chromosomes. Chromosome 1 spans about 249 million nucleotide base pairs, which are the basic units of information for DNA. It represents about 8% of the total DNA in human cells.
Wikipedia · Chromosome 1