DNA – DEOXYRIBONUCLEIC ACID
DNA is sometimes called “the blueprint of life” because it contains the code, or instructions for building and organism and ensuring that organism xxxs correctly. Just like a builder uses a blueprint to build a house, DNA is used as the blueprint, or plans, for the entire organism.
It is the chemical component of chromosomes, which are located in the nucleus of every cell. Stretches of DNA (or stretches of chromosomes) code for genes.
Gene – 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.
The structure of DNA was established by James Watson and Francis Crick.
The shape of the DNA molecule is a double-helix (like a twisted ladder). The sides of the ladder are composed of alternating sugars (deoxyribose) and phosphates. The rungs of the ladder are composed of nucleotides.
Nucleotides (also called Bases)
Adenine, Thymine, , Guanine, Cytosine or A, T, G, C
Nucleotides pair in a specific way – called the Base-Pair Rule
Adenine pairs to Thymine
Guanine pairs to Cytosine
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)
For instance, a stretch of DNA could be AATGACCAT – which would code for a different gene than a stretch that read: GGGCCATAG