Dictionary > Supercoiling

Supercoiling

supercoiling
(Science: molecular biology) In circular DNA or closed loops of dNA, twisting of the DNA about its own axis changes the number of turns of the double helix.
If twisting is in the opposite direction to the turns of the double helix, i.e. Anticlockwise, the dNA strands will either have to unwind or the whole structure will twist or supercoil termed negative supercoiling.
If twisting is in the same direction as the helix, clockwise, which winds the dNA up more tightly, positive supercoiling is generated. DNA that shows no supercoiling is said to be relaxed
Supercoiling in circular DNA can be detected by electrophoresis because supercoiled dNA migrates faster than relaxed DNA. Circular DNA is commonly negatively supercoiled and the DNA of eukaryotes largely exists as supercoils associated with protein in the nucleosome. The degree of supercoiling can be altered by topoisomerases.


You will also like...

Hominid
The Hominids

The hominid family diversified from the apes around 6 to 8 million years ago. Since then, the evolutionary path has prov..

sponge
Primitive Animals

Life, as we know it today, is presumed to have started in the sea and many of them were likely eukaryotic animal-like or..

human brain structure
The Conscious & Unconscious Nervous System

This tutorial elaborates on how the nervous system works, particularly at the tissue level of the brain. There are three..

mRNA
Protein Synthesis

Part of the genetic information is devoted to the synthesis of proteins. mRNA, a type of RNA, is produced as a transcri..

Human gastrointestinal tract
Human Biology – Food and Digestion

This tutorial recognizes the importance of food as a source of energy that will fuel many biological processes. A good d..

Digestion and Absorption of Food
Digestion and Absorption of Food

The gastrointestinal system breaks down particles of ingested food into molecular forms by enzymes through digestion and..