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DNA and Hydrogen Bonds
Transcript of DNA and Hydrogen Bonds
What would happen if they didn't exist?
If hydrogen bonds did not exist DNA would not be able to adopt a double helix structure.
Without such bonds, DNA would have to exist in either a plasmid or naked structure
This would allow for a multitude of possible genetic variations and disruptions which may lead to an increase in cancerous cells and low life expectancy rates (mutations)
Structure of DNA
Hydrogen bonding & DNA replication
The process of DNA replication is when the original DNA strand are used as templates to construct new DNA strands.
The weakness of the hydrogen bonds is important for DNA relication and the stability of the hydrogen bonds between A and T or between G and C.
This prevents permanent mistakes from happening.
When hydrogen bonds are heated, the bond is denatured and becomes disfunctional.
An example is overexposure to UVB radiation.
Prolonged exposure to this radiation can cause the heat to produce enough energy for the hydrogen bonds to lose stability in the DNA.
This then prevents the DNA from properly coding for proteins. Can also cause mutations if duplication is in progress.
Hydrogen bonds and DNA
Weak chemical bonds that occur between hydrogen atoms and more electronegative atoms (oxygen, nitrogen, fluorine).
Can either be intermolecular (occur between molecules) or intramolecular (occur within different parts of a single molecule).
They do not involve the exchange or sharing of electrons like covalent and ionic bonds.
Their weak attraction is similar to that of opposite poles of a magnet.
Occur over short distances, can be easily formed and broken.
Why are hydrogen bonds important to DNA?
They are one of the factors responsible for stability of DNA. (Internal and external hydrogen bonds stabilize the DNA molecule)
The 2 strands of DNA stay together due to H bonds that occur between complimentary nucleotide base pairs.
Two hydrogen bonds occur between base pairs.
What is DNA?
Building blocks for the body
Heredity material in humans and almost all other organisms
Mostly located in cell nucleus
Small amounts occur in mitochondria
Made up of 4 nitrogenous base pairs: Adenine, Thymine, Guanine, Cytosine. (A-T, C-G)
Each base is attached to a sugar molecule and phosphate molecule (sugar phosphate backbone)
Form a double helix
Binding nitrogenous bases together are hydrogen bonds.
Watson R. (2008). What if there were no such thing as a hydrogen bond?. Young scientists J.http://www.ysjournal.com/text.asp?2008/1/1/13/44013
DNA labs (n.d) What is DNA? Retrieved from http://www.dnalabs.com/dna-test-menu/what-is-dna.aspx
HowStuffWorks (n.d) How DNA works. Retrieved from http://science.howstuffworks.com/life/cellular-microscopic/dna1.htm
McEntire, A. (2011) The Importance of Hydrogen Bonds in DNA. Natural Sciences Poster Sessions. Paper 6.
Ophardt. E. C. (2003) Intermolecular forces: Hydrogen Bonding. Retrieved from http://www.elmhurst.edu/~chm/vchembook/161Ahydrogenbond.html
(DNA labs, n.d)
(Orphadt. E. C 2003)