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.
DNA Chapter 10
The Code of Life
Pyrimidines and Purines
thymine cytosine adenine guanine
Hydrogen bonds between bases hold the strands together
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.
Translation (Protein Synthesis)
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.
Viruses-DNA or RNA in a protein coat
Cancer results from mutations in genes that control cell division.
Separates fragments by their size