DNA is composed of two strands, the wind around each other. Every strand has repeating devices of a nitrogenous base, deoxyribose sugar, and a phosphate group. There are numerous interactions current within a strand and between 2 strands that stabilize the DNA.

You are watching: What type of chemical bond joins the bases of complementary dna strands

Credit: spectral resolution/Shutterstock.com

Covalent bond (intrastrand bonds)

Each strand is composed of the following:

Base (Adenine, Thymine, Guanine, Cytosine)Deoxyribose sugarPhosphate group

There are four bases: Adenine and also Guanine (purines); Cytosine and Thymine (Pyrimidines). Purines have actually two carbon-nitrogen ring while pyrimidines have a single carbon-nitrogen ring. Thus, there are four different nucleotides that have the right to be included into DNA.

Based on which basic is attached, the nucleotides are referred to as 2’-deoxyadenosine triphosphate, 2’-deoxycytidine triphosphate, 2’-deoxyguanosine triphosphate, or 2’-deoxythymidine triphosphate. Every of this bases is associated to 1’-carbon the the deoxyribose sugar.

In an unattached and complimentary nucleotide, over there is a triphosphate team on the 5’-carbon the the deoxyribose sugar. However, when a nucleotide is included into a DNA strand, it loses 2 of the phosphate groups and only one phosphate group is included to the DNA strand.

Related Stories

This addition involves development of a covalent bond called the phosphodiester bond. This is formed in between the 5’-phosphate group of one nucleotide and also the 3’-OH group of another nucleotide developing a sugar-phosphate backbone that DNA.

Hydrogen bonds

The hydrogen bonds in between the basic pairs type the double helical structure of DNA. Over there is no exchange or sharing of electrons in hydrogen bond as seen in covalent or ionic bonds. Hydrogen bonds take place over short distances and can be quickly formed and also broken. Return individually every hydrogen shortcut is much weaker than the covalent bond, they have the right to stabilize the twin helix since of their large numbers.

This pairing is very specific: adenin pairs v thymine and also cytosine pairs v guanine. This selective pairing is referred to as ‘complementary base pairing’. A-T pair forms two hydrogen bonds, when C-G pair forms three. The sugar-phosphate chains type the backbone of the ladder-like DNA structure and these basic pairs form the rungs. The width of every of this ‘rungs’ are the exact same as it requires one purine (A or G) and one pyrimidine (C or T) base.

Stacking interactions

a) Hydrophobic effects

DNA has an interesting arrangement wherein the non-polar, uncharged bases are existing in the internal of the structure, if the negatively fee phosphates are current on the outside. Together the cellular environment is aqueous and also polar, the hydrophobic bases in the internal of the helix are kept away from the bordering water and the hydrophilic heads space exposed and also interact through the exterior water. This property boosts the solubility that DNA in water.

b) van der Waals forces

The nitrogenous bases stack upon one one more are spaced based on their van der Waals distance. Van der Waals street is the distance at which 2 molecules are attracted to every other. If this street reduces, the electron of the 2 molecules may overlap leading to repulsion. These pressures are really distance dependent and are inversely proportional to the sixth power of distance (r6 ). Return a solitary van der Waals interaction has a very little effect on the all at once structure of DNA, the net impact of several interactions command to comprehensive stability.

c) Ionic interactions

The electrostatic (ion-ion) repulsion that the negatively charged phosphates ~ above the external can do DNA potentially really unstable. However, magnesium ions (Mg2+) and cationic proteins together with arginine and also lysine residues connect with the negative charged groups in the DNA and also stabilize it.

The strength and stability that DNA stacking interactions has actually been scientifically proved by demonstrating that the use of compound (urea, formamide) the interfere with hydrogen bonds perform not different the strands completely, arguing the presence of added forces at work.


Written by

Dr. Surat P

Dr. Surat graduated through a Ph.D. In cell Biology and also Mechanobiology from the Tata academy of basic Research (Mumbai, India) in 2016. Before her Ph.D., Surat studied for a Bachelor of scientific research (B.Sc.) level in Zoology, throughout which she to be the recipient of an Indian Academy of sciences Summer Fellowship to study the proteins connected in AIDs. She produces feature short articles on a wide range of topics, together as medical ethics, data manipulation, pseudoscience and also superstition, education, and human evolution. She is passionate about science communication and writes short articles covering all areas of the life sciences.

Please use one of the complying with formats to mention this post in your essay, record or report:


P, Surat. (2019, February 26). Interactions That organize DNA Together. jajalger2018.org. Re-cover on November 06, 2021 native https://www.jajalger2018.org/life-sciences/Interactions-That-Hold-DNA-Together.aspx.


P, Surat. "Interactions That organize DNA Together". jajalger2018.org. 06 November 2021. .


P, Surat. "Interactions That host DNA Together". jajalger2018.org. Https://www.jajalger2018.org/life-sciences/Interactions-That-Hold-DNA-Together.aspx. (accessed November 06, 2021).

See more: 'The Incredibles 2': In What Year Does The Incredibles Take Place


P, Surat. 2019. Interactions That host DNA Together. jajalger2018.org, viewed 06 November 2021, https://www.jajalger2018.org/life-sciences/Interactions-That-Hold-DNA-Together.aspx.