Advanced Concepts in DNA Chapter 10

DNA = deoxyribonucleic acid Made of repeating nucleotides (subunit) Nucleotide = sugar (deoxyribose), phosphate, base 4 bases – adenine, guanine, cytosine, thymine A & G = larger purines C & T = smaller pyrimidines

Chargaff (1949) – studies  A always same % as T C always same % as G - so, _______________ = Chargaff’s Rules

Franklin, Watson, Crick Double helix held together by weak Hydrogen bonds Two strands run in opposite directions = antiparallel Are complementary

Genes = section of DNA that codes for protein Alleles = different forms of gene Homozygous & heterozygous alleles Homologous chromosomes = paired chromosomes (23 pairs – 1 from each parent)

RNA = ribonucleic acid 3 structural differences b/t DNA & RNA DNA RNA Sugar = deoxyribose Sugar = ribose Base = thymine Base = uracil Double helix Single stranded

Transcription = DNA acts as template to make RNA

Translation 3 RNAs work together to assemble amino acids into a protein. Every 3 base letters of mRNA stands for an amino acid = codon Amino acids make up proteins

Mutations = heritable changes in a gene  mistakes Can be : - neutral - harmful - helpful

Variation in DNA DNA Fingerprinting – used to compare reference samples to evidence samples Examine several markers – a sequence of DNA base pairs associated with a specific trait. The more matching markers, the more likely two samples from same person