all cells require some form of instructions to be able to function properly They need guidelines rules codes for making materials in the cell and that code is DnA Dna stands for deoxyribonucleic Acid de for the name of The Sugar N And a for Nucleic acid Dna contains the information that Determines inherited Characteristics it has the code for making proteins Dna is found in the nucleus of eukaryoticcells and in the cytosol of prokaryotes if We take a closer look at the chromatin inside the nucleus. We can see the structure of the dNa the Dna has repeating subunits and those [subunits] are called Monomers or Nucleotides specifically The Nucleotide has [3] main parts a phosphate group [a] sugar and a nitrogen base in Dna the name of the sugar is Deoxyribose which is part of DnA's name and there are 4 nitrogen bases in DNa the [bases] are thymine Adenine cytosine and guanine? two of the bases are purines Which have a two ring structure and two bases are pyrimidines which have a 1 ring structure Adenine and Guanine are purines cytosine and thymine are pyrimidines I remember the pyrimidines are the bases with a [y] in their name just [like] pyrimidines has a y in its name appearing always pairs with [a] pyrimidine and the slanted shape of the DNa molecule Causes it to form a spiral or helix Because Dna is double-stranded we use the phrase double helix to describe its structure There are four scientists who are credited with discovering the shape of DnA and they are Watson crick? Wilkins and Franklin all of them received a nobel prize [for] their work except for rosalind Franklin she died before the prize was given Each of these scientists played a role in piecing together the structure of DnA They learned that along the sides of the molecule was a backbone made of alternating sugar and phosphate Molecules on [the] inside like the rungs of a ladder are the nitrogen bases Adenine and Thymine form Hydrogen bonds together Sata seen and Guanine Form Hydrogen bonds together To help me remember which base is linked together. [I] think [of] writing the letters a And t both use straight Lines C and g use curved lines [I] also know that a and t have two hydrogen bonds, but C and g have three hydrogen bonds by saying 82 Cg three, silly things like this are actually a great memory tool Strands of Dna are said to be complementary to one another because a will always be with t and C will always be with G Based on the number of Hydrogen bonds that they want to make you can predict the complementary strand if you know the other strand So let's use all of that knowledge about Dna and see if we can identify the parts of this blank DNa molecule The easiest to label are the Deoxyribose sugars and phosphates They make up the outside of the molecule Deoxyribose is a pentagon shape and the phosphate is just a small molecule in between next we need to remember a rhyme 82 Cg 3 so the Nucleotides with two hydrogen bonds must be a and t and the ones with three are C and g To tell which one is which you need to know that pyrimidines have one ring and purines have two so cytosine and thymine are the pyrimidines [so] they're the one ring bases adenine and guanine are the two ringed bases and now you have a labeled DNa molecule? thanks for watching this episode of Teacher's pet don't forget to like and subscribe and follow me on Twitter at science pet