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[B][COLOR="blue"][SIZE="5"][CENTER]DNA - DEOXYRIBONUCLEIC ACID[/CENTER][/SIZE][/COLOR][/B]

[center][img]http://www.biologycorner.com/resources/DNA-colored.gif[/img][/center]

[B]DNA is the blueprint of life (has the instructions for making an organism)

established by James Watson and Francis Crick [/B]

[COLOR="blue"]---codes for your genes

---shape of a double helix

---made of repeating subunits called nucleotides [/COLOR]

[B][COLOR="blue"]Gene [/COLOR][/B]- a segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color..etc), a gene is a stretch of DNA.

[COLOR="blue"][B]Nucleotide[/B][/COLOR] - consists of a sugar, phosphate and a base

Nucleotides (also called Bases)

[B]Adenine, Thymine, , Guanine, Cytosine or A, T, G, C[/B]

Nucleotides pair in a specific way - called the Base-Pair Rule

Adenine pairs to Thymine

Guainine pairs to Cytosine

[COLOR="blue"]There is a double bond between A and T.[/COLOR]

[COLOR="blue"]There is a tripple bond between C and G.[/COLOR]

Memory helper - think "A T Granite City") - which is where you live

*The rungs of the ladder can occur in any order (as long as the base-pair rule is followed)

[B][COLOR="blue"][SIZE="4"]How the code works[/SIZE][/COLOR][/B]

For instance, a stretch of DNA could be AATGACCAT - which would code for a different gene than a stretch that read: GGGCCATAG.

Those 4 bases have endless combinations just like the letters of the alphabet can combine to make different words.

[B][COLOR="blue"][SIZE="4"]DNA REPLICATION[/SIZE][/COLOR][/B]

Replication is the process where DNA makes a copy of itself.

[B]Why does DNA need to copy? [/B]

Cells divide for an organism to grow or reproduce, every new cell needs a copy of the DNA or instructions to know how to be a cell. DNA replicates right before a cell divides.

DNA replication is semi-conservative. That means that when it makes a copy, one half of the old strand is always kept in the new strand. This helps reduce the number of copy errors.