Download File - Chereese Langley

comprehensive project.
By: Chereese Langley
Pd. 6/7
3-27-12
Deoxyribonucleic acid contains genetic information. Also known as DNA. The double
helix is in the DNA molecule. The double helix is a pair of parallel helices
intertwined about a common axis. Adenine, thymine, cytosine, and guanine are a
compound that is one of the four constituent bases of nucleic acid which are all
apart of this DNA molecule. The guanine occurs in guano and fish scales.
The genetic code is the code defines how sequences of three nucleotides,
called codons, specify which amino acid will be added next during protein
synthesis. With some exceptions, a three-nucleotide codon in a nucleic acid
sequence specifies a single amino acid.
Adenine and guanine are purines. Purines are the larger of the two types of
bases found in DNA.
Cytosine and thymine are pyrimidines. The 6 stoms (4 carbon, 2 nitrogen) are
numbered 1-6. Like purines, all pyrimidine ring atoms lie in the same plane. The
deoxyribose sugar of the DNA backbone has 5 carbons and 3 oxygens. The carbon
atoms are numbered 1', 2', 3', 4', and 5' to distinguish from the numbering of the atoms of
the purine and pyrmidine rings. The hydroxyl groups on the 5'- and 3'- carbons link to the
phosphate groups to form the DNA backbone.
The nitrogen base is the type of molecule that forms an important part of
nucleic acid, composed of a nitrogen-containing ring structure. Hydrogen
bonds between bases in opposing complementary strands link the two strands
of a DNA double helix.
The second of Chargaff's rules (or "Chargaff's second parity rule") is that the composition
of DNA varies from one species to another; in particular in the relative amounts of A, G,
T, and C bases. Such evidence of molecular diversity, which had been presumed absent
from DNA, made DNA a more credible candidate for the genetic material than protein. In
2006, it was shown that this rule applies to four of the five types of double stranded
genomes; specifically it applies to the eukaryotic chromosomes, the bacterial
chromosomes, the double stranded DNA viral genomes, and the archival chromosomes.