dna (deoxyribonucleic acid)

DNA(Deoxyribonucleic Acid)History and Structure

C10L28C12

During Mitosis we can see Chromosomes

Chromosomes and DNA

Chromosomes are made of

DNA

Chromosomes and DNA

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DNA HistoryDNA Structure

Today’s Goals

What is DNA?

DNA Nitrogen BasesChargaff's Rule

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DNA holds all the genetic information that determines an

organism’s traits.

What is DNA?

Hair Color

Eye Color

Height

Skin Tone

Within the structure of DNA is the information for life—the complete instructions for manufacturing all

the proteins for an organism.

What is DNA?

o DNA achieves its control by determining the structure of proteins.

* Enzymes (a type of protein) control the chemical reactions needed for life.• Eating, running, even thinking

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DNA HistoryDNA Structure

Today’s Goals

What is DNA?

DNA Nitrogen BasesChargaff's Rule

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Important clues to the structure of DNA

1. Twisted strands (helix)2. Angle suggested 2

strands ( double-helix)3. Nitrogen bases near the

center of the molecule

Rosalind FranklinStudied DNA structure with X-ray diffraction

1952

James Watson

and Francis CrickBuilt a DNA model based on

the clues from Franklins X-ray diffraction

1953

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DNA HistoryDNA Structure

Today’s Goals

What is DNA?

DNA Nitrogen BasesChargaff's Rule

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DNA is a Double HelixA double helix looks like a twisted ladder.

The Double Helix Building Blocks

A DNA strand is a polymer.

They are very long!It’s length is what allows DNA

to hold so much information

The repeating subunits of DNA are called

nucleotides

Nucleotide StructureComposed of 3 parts

Phosphate

DeoxyriboseSugar

NitrogenBase

•There are 4 possible bases.•Broken down into 2 categories

Nucleotide Structure• The phosphate

groups and deoxyribose (sugar) molecules bond to form the backbone of the chain

• The nitrogenous bases stick out like the teeth of a zipper.

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DNA HistoryDNA Structure

Today’s Goals

What is DNA?

DNA Nitrogen BasesChargaff's Rule

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PURINESPurines have two

ringsPyrimadines have

one ring

PYRIMIDINES

Types of Nitrogen basesThere are two types of nitrogen bases

PURINES

PYRIMIDINES

Types of Nitrogen basesThere are two types of nitrogen bases

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DNA HistoryDNA Structure

Today’s Goals

What is DNA?

DNA Nitrogen BasesChargaff's Rule

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How the double helix is formed

Nitrogen bases bond to one another to connect the two strands

But only certain bases can bond to one another

1 PURINE MUST BOND TO 1 PYRIMADINE

Guanine only bonds to

Cytosine

Chargaff’s Rule – Base Pairing

Adenine only bonds to

ThymineAt The

Grand Canyon

OVERVIEW