Dr. Vincent C. Giampapa presented DNA repair product: AM PM Essential
Essential Question: What is the overall structure of DNA.
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Transcript of Essential Question: What is the overall structure of DNA.
3
DNA
• DNA is often called the blueprint of life.
• DNA contains the instructions for making proteins within the cell.
DNA(deoxyribonucleic acid)
Functions
1. Storage of genetic information2. Expression of the genetic message (information). 3. Self-duplicate (replicates itself)
DNA’s major function is to code for proteins.
• By the early 1900’s it was known that the chromosomes carry the genetic information
• Chromosomes consist of DNA (deoxyribonucleic acid)
Discovery of DNA
Discovery of DNA- Rosalind Franklin produced X ray
photographs of DNA
- helped Watson and Crick develop their model
- Did NOT win Nobel Prize for her work
Watson and Crick’s Double Helix Model explained:
1. How replication of DNA during mitosis produces exact copies for the daughter cells.
2. The double helix structure, two nucleotide strands are antiparallel (complementary).
3. How DNA acts as a code, specifying how proteins are made by the cell.
Structure of DNA
• DNA consists of two molecules that are arranged into a ladder-like structure called a Double Helix.
• A molecule of DNA is made up of millions of tiny subunits (monomers) called Nucleotides.
• Each nucleotide consists of:1. Phosphate group2. Pentose sugar3. Nitrogenous base
Structure of DNA
- 4 different nucleotides are used to make the DNA molecule
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Thymine (T)
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Types of Bases
• Double ring PURINESAdenine (A)Guanine (G)
• Single ring PYRIMIDINESThymine (T)Cytosine (C)
T or C
A or G
copyright cmassengale
Chargaff’s Rule:
• Adenine and Thymine always join together, base pairing
A T• Cytosine and Guanine always join
together, base pairingC G
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One Strand of DNA• The backbone of
the molecule is alternating phosphates and deoxyribose sugars
• The nitrogenous bases are inside of the double helix.
phosphate
deoxyribose
bases