DNA Deoxyribonucleic Acid DNA Structure What is DNA

DNA Deoxyribonucleic Acid

DNA Structure

What is DNA? n n n The information that determines an organisms traits. Stores and passes on genetic information from one generation to the next. DNA produces proteins which gives it “The power” Many things contain and are made of proteins. Skin, hair, bones, etc are made of proteins.

What is DNA? Cont’d n Enzymes are special proteins. n Enzymes control chemical reactions needed for life. n DNA contains all the information for making all and any proteins for human life.

DNA Structure: DNA is made of repeating subunits called nucleotides. n Nucleotides have three parts: n – Simple sugar – Phosphate group – Nitrogen base

1 Nucleotide Phosphate Group Nitrogen Base Sugar (Deoxyribose)

DNA Structure n The simple sugar is called deoxyribose. phosphate group is made of phosphate and oxygen.

DNA Structure n Four possible Nitrogen Bases: – Thymine (T) – Adenine (A) – Cytosine (C) – Guanine (G)

DNA “Backbone” n Nucleotides join together to form long chains. “Teeth” n The phosphate group of one nucleotide joins together with the deoxyribose sugar of an adjacent nucleotide.

DNA n Nitrogen up bases pair – Adenine & Thymine (A-T) – Cytosine & Guanine (C-G) Complementary bases

Watson & Crick and Franklin, 1953 Rosalind Franklin is the first one to see the DNA n Watson and Crick Proposed DNA is put together like a “twisted zipper” n DNA = 2 chains of nucleotides joined by nitrogen bases n

Watson & Crick, 1953 Double Helix n Double = DNA has two strands n Helix = twisted like a spring, “spiral”

Importance of Sequencing n The sequence of the four different nucleotides determines what organism is created. n For instance: T-A-A-G-C-A is different than A-G-C-A-A-G n Another example: E-A-R-T-H is different than H-E-A-R-T vs.

Importance of Sequencing n The more similar the order of nucleotides are, the closer the relationship between 2 organisms