Presented by, Kenneth & Autumn Biology Module #5 DNA Presented by, Kenneth & Autumn

What is DNA? DNA is a double helix of two chemical chains called nucleotides. DNA stores the genetic instructions required in the making of all life in its nucleotide bases.

What are Nucleotides? Nucleotides are the two individual chains that make up the double helix of a strand of DNA. Nucleotides themselves are comprised of deoxyribose, a phosphate group, and a nucleotide base. Deoxyribose -- Simple sugar that contains five (5) carbons Phosphate Group -- Arrangement of phosphorous, hydrogen, and oxygen atoms Nucleotide Base -- A base comes in four (4) varieties which are adenine, thymine, guanine, and cytosine

What is Hydrogen bonding? Hydrogen bonding is the strong attraction between hydrogen atoms and certain other atoms (usually oxygen or nitrogen) in specific molecules which holds together the two nucleotide bases that make up DNA. The attraction between the atoms in hydrogen bonding is about 15% as strong as the attraction between two atoms that have a true chemical bond linking them. The hydrogen bonds in DNA are strong enough to keep the two chains together in a double helix, but they are weaker than a true chemical bond. The two helixes in DNA can easily unravel.

Varieties of Nucleotide Bases and how they correlate to Hydrogen Bonding Hydrogen bonding is drastically dependent on the types of molecules involved in the process, which means that only specific varieties of nucleotide bases can be linked during hydrogen bondage. Adenine can only bond to thymine, and vice-versa, thymine can only bond to adenine The same goes for cytosine, which can only bond with guanine, and of course guanine, which only bonds with cytosine. Adenines -- Thymines Cytosines -- Guanines

Simplified sample of DNA:

DNA double helix, emphasizing the nucleotide bases:

Storage of Genetic Information DNA stores all of its important information regarding the creation of life in the sequences of nucleotide bases that make up the molecule, which are then decoded by cells.

We hope you’ve learned a few things about DNA during this presentation. By Autumn and Kenneth “Did I do that?”----