DNA: Structure. DNA Structure and Purpose In simplest terms, DNA is a blueprint for life. It is made...
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Transcript of DNA: Structure. DNA Structure and Purpose In simplest terms, DNA is a blueprint for life. It is made...
DNA: Structure
DNA Structure and Purpose
• In simplest terms, DNA is a blueprint for life. • It is made up of genes which hold the
information for making proteins within the cell– Proteins in turn help make up everything in your
body!
• DNA is a very long polymer made up of monomers called nucleotides
• The basic 3D shape of DNA is called the double helix
• The double helix looks like a twisted ladder or zipper.
DNA’s Structure C G
A T
Sugar-phosphate backbone
Nucleotide
Hydrogen bonds
• The nitrogen bases are connected by Hydrogen bonds
• The backbone (sides) are connected by
Covalent bonds.
Covalent bonds
How is DNA held together??
1 monomer!!! Aka nucleotide
PhosphateNitrogen
baseDeoxyribose
8 monomers making a small section of DNA
• Sides of DNA are always made up of a Phosphate and 5 carbon sugar (deoxyribose).
• Middle or rungs of DNA are always made up of 4 different nitrogen base pairs.
Hydrogen bondsCovalent bonds
Nitrogenous Bases2. PURINE
– 2 rings– Adenine (A)– Guanine (G)
**Remember: “PUGA2”
1. PYRIMIDINE– 1 ring – Pyrimidines have “y”
**Remember:
*Cytosine (C)
*ThYmine (T)
Nitrogen Base pairing
• One pyrimidine and one purine will ALWAYS pair up.
• A pairs with T• G pairs with C
Location and Form of DNA• Prokaryotic DNA is located in the
cytoplasm, usually in a circular form
• Eukaryotic DNA is located inside the nucleus in the form of chromosomes
• How does all that DNA fit into the nucleus? Hopefully you remember this picture from cell division!
Review!!!• What does A pair with?
• What does C pair with?
• What makes up the sides of a the DNA strand?
• What are the base pairs held together by?
• What consists of a phosphate group, 5-carbon sugar and a nitrogen base?