DNA Deoxyribonucleic Acid

DNA is called: the blueprint for life!

What is DNA? DNA contains the instructions for making proteins within the cell. The information that determines an organism’s 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.

Why do we study DNA? 1. It tells about life on earth 2. Medical benefits and research 3. To enhance food crops and farming animals and plant

Definitions Chromosomes are a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes. Genes are:a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

What does it look like: The DNA molecule looks like a twisted ladder. It is called a double helix.

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

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

1 Nucleotide Phosphate Group Nitrogen Base Sugar (Deoxyribose)

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

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

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

Adenine & Thymine (A-T) DNA Nitrogen bases pair up 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 Watson and Crick Proposed DNA is put together like a “twisted zipper” DNA = 2 chains of nucleotides joined by nitrogen bases

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

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

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

1 Nucleotide Phosphate Group Nitrogen Base Sugar (Deoxyribose)