BISC 101 Lecture Notes - Helicase, Dna Replication, Ion
Document Summary
Lecture #4: dna structure and replication: deoxyribonucleic acid, genetic material males up traits of an individual species, passed on to next generation. Structure: sugar (deoxyribose, nitrogen base, phosphate group, 30% each a, t, 20% each g, c, a + g are purines, t +c are pyrimidine. Fig 16. 5, 16. 8: semi- conservative model, 2 strands separate, each strand serves as a template to produce a complementary strand. Details of replication: origins of replication, specific dna sequence, proteins attach causes strands to separate, dna polymerase adds new nucleotides, energy for replication. Nucleotides occur as triphosphates (3po4), 2po4 are release, energy is produced. Orientation of dna strand: antiparallel, opposite directions. Replication: nucleotides added only to the 3" end; new strand goes from 5" 3", fragments joined by dna ligase, dna polymerase can only add nucleotides to an existing strand, primer. Initiates elongation of the strand: added by primase enzyme, rna converted to dna. Each okazaki fragments must also have a primer.