DNA Chapter 10. The Code of Life. History Griffith Hershey and Chase Chargaff Linus Pauling Maurice Wilkins Rosalind Franklin Francis Crick James Watson. Model Double Helix Building Blocks-Nucleotides Sugar-Deoxyribose Phosphate Nitrogen Base. Types of Nitrogen Bases.
The Code of Life
Pyrimidines and Purines
thymine cytosine adenine guanine
Each base pairs with a complementary partner
A pairs with T
G pairs with C
DNA is made up of building blocks called nucleotides. A nucleotide consists of a phosphate, a sugar (deoxyribose) and a nitrogen base.
There are two kinds of bases-purines(adenine and guanine) and pyrimidines(cytosine and thymine). Purines have a double ringed structure and pyrimidines have a single ringed structure.
A pairs with T and they join with a double hydrogen bond and C pairs with G and they join with a triple bond. DNA is anti-parallel. Its structure is called a double helix.
The “words” of the DNA “language” are triplets of bases called codons.The codons in a gene specify the amino acid sequence of a polypeptide.
Where? At a ribosome in the cytoplasm
What? enzymes and energy, mRNA, tRNA, rRNA, amino acids
First a small ribosomal subunit joins mRNA at a start codon-AUG. The appropriate tRNA comes to join the mRNA. Large ribosomal sub unit joins. Another tRNA comes bringing the correct amino acid with it. A peptide bond forms between the amino acids, and the 1st tRNA leaves.
Colon Cancer division.
Separates fragments by their size