Tertiary structure of DNA
The tertiary structure is the arrangement that the double-stranded DNA fiber adopts as it associates with proteins to form chromosomes. The tertiary structure varies depending on whether it is prokaryotic or eukaryotic organisms:
- In prokaryotes, DNA folds like a superhelix, generally in a circular shape and associated with a small amount of proteins. The same occurs in cellular organelles such as mitochondria and in chloroplasts.
- In eukaryotes, given that the amount of DNA in each chromosome is very large, the packaging has to be more complex and compact; This requires the presence of proteins, such as histones and other proteins of a non-histonic nature (in sperm these proteins are protamines).