What is DNA?
DNA stands for Deoxyribonucleic acid and it is located inside the cells nucleus. DNA holds all the information about your genetics and heredity. Everyone has their own different set of DNA code which is why know one is the same. DNA codes for proteins that are essential to life.
What is the Structure of DNA?
This is a picture of a double helix
DNA looks like a twisted ladder called a double helix. DNA is made up of nucleotides which are made up of a phosphate group, a five carbon sugar and a nitrogen base. Also inside DNA there is a sugar/phosphate backbone that make up
the sides. Atoms within two strands are held together by covalent bonds and the base pairs are held together by hydrogen bonds.
the sides. Atoms within two strands are held together by covalent bonds and the base pairs are held together by hydrogen bonds.
What bonds with what?
In DNA certain bonds pair with each other because of the size of a DNA strand. for example a bond between two purines would be too wide but a bond with a purine and a prymidine always fits perfectly. The 4 nitrogen bases are Thymine, Adenine, Cytosine, and Guanine. In DNA Thymine always pairs with Adenine and Cytosine always pairs with Guanine because one is a purine and one is a prymidine.
How does DNA replication occur?
This image shows the process of DNA replication.
DNA replication occurs during the S phase of cell division Step one of replication is when the helicase unzips the DNA strands by breaking the bonds. In step two the DNA polymerase inserts new complementary bases in the DNA. In the last step the DNA polymerase proof reads the sequence and sends it out. The result is two new strands of DNA that are exactly the same as the original strand. Many people say that DNA replication is is called semi-conservative cause each strand has an old part and a new part.