BSC 2010C Lecture Notes - Lecture 14: Nucleic Acid Double Helix, Pentose, Base Pair
Document Summary
Hereditary information: encoded in chemical language of dna. But chromosomes are both dna and proteins so . Dna declared winner by studying bacteria and viruses that infect them. Double helix and base pair rules allows for replication mechanism. Watson & crick deduced dna was double helix. Base pairing rules: a paired only with t & g paired only with. Dna replication : parent dna unwinds & 2 new daughter strands built using base-pairing rules. Before new dna made: existing double stranded parental dna unwound & kept apart. Single-strand binding proteins- stabilizes separated strands and keeps them apart. Topoisomerase- prevents over twisting ahead of replication fork. Primase: makes short rna primer using dna strand as template9. Adds new dna nucleotides to 3" end of rna primer, following base pair rules. Also can only ass to 3" end (needs free -oh of last deoxyribose to create new bond) New dna strand: only elongates 5" to 3" direction.
