Structure of Nucleic acid (DNA&RNA)
Look at the structure DNA. The chromosomes in the nucleus are highly quelled and condensed packages. When you zoom in on DNA you can see that the DNA is arranged into functional units called gene. Chromosomes gene and nucleotides are all DNA. DNA molecule there are three components to nucleotide. The Deoxyribose sugar shown in blue is a 5% carbon ring although. You can see a carbon is represented by the meeting up two lines on the pentose ring. The carbons are numbered clockwise starting from the central oxygen the phosphate group bonds to the fifth carbon. That on a third carbon there is a hydroxyl or oooh group will discuss this in just a minute. The nitrogen base shown in orange is on carbon number one there are four nitrogen bases in DNA they are Adenine Guanine Cytosine and Thymine those for nitrogen bases are actually divided into two different classes The Purines have double rings and are made up of Adenine and Guanine. The Pyrimidines have a single ring and are made up of Thymine and Cytosine. DNA is a double-stranded molecule noticed that Adenine A forms bonds with thymine T. And Guanine G forms bonds with Cytosine C. The bonds that hold these two strands of DNA together are called hydrogen bonds. These hydrogen bonds give DNA its characteristic unical shape. You can figure out the sequence up the other strand because a always pairs with T and G always pairs with C. The bond that holds the nucleotides together on the single strand of the DNA molecule a bond with the oooh group on the nucleotide it this is called a Phosphodiester bond. And these bonds are highlighted in yellow the alternating string up sugar and phosphate bond form the backbone up the DNA strand. The phosphate or five prime end is on top and the oooh or three prime end is on the bottom. That's right it's the mirror image so three prime end is up, five prime end is down. They are called antiparallel this is going to become very important when we study how DNA replicates. RNA nucleotide are very similar to DNA nucleotides. The four bases in RNA are Adenine Guanine Cytosine and Uracil. The difference is found on the number two carbon do you see the hydroxyl group. This extra which makes it difficult for RNA to form hydrogen bonds with the nucleotides. That's why RNA is almost always single-stranded and because it is single-stranded RNA can leave the nucleus to small nuclear pores and travel into the cytoplasm. mRNA is shown in purple and is the copier of RNA that is made directly from the DNA sequence. The next to mRNA are necessary for making protein Ribosome RNA or rRNA is shown in brown and along with proteins is what makes up the ribosome. The last half of RNA call transfer RNA or tRNA is shown in green and it functions to bring amino acids to the ribosome for protein assembly the manipulation of genetic information specifically.