文档介绍：Chapter 6 Microbial ics Structure and Function of ic Materials DNA & RNA DNA=deoxyribonucleic acid RNA=ribonucleic acid Basic building blocks: Nucleotides Phosphate group Pentose sugar Nitrogenous base Structure of DNA Double stranded (double helix) Chains of nucleotides 5’ to 3’(strands are anti-parallel) Complimentary base pairing A-T G-C DNA Structure Phosphate-P Sugar-blue Bases-ATGC DNA Replication Bacteria have closed, circular DNA Genome: ic material in anism E. coli 4 million base pairs 1 mm long (over 1000 times larger that actual bacterial cell. How it can be put into a cell? DNA takes up around 10% of cell volume DNA Replication occurs at the replication fork 5’ to 3 ‘ DNA helicase-unzips + parental DNA strand that is used as a template Leading stand (5’ to 3’-continuous) DNA polymerase-joins growing DNA strand after nucleotides are aligned (complimentary) Lagging strand (5’ to 3’-not continuous) RNA polymerase (makes short RNA primer) DNA polymerase (extends RNA primer then digests RNA primer and replaces it with DNA) DNA ligase (seals Okazaki fragments-the newly formed DNA fragments) Replication Fork 1 解旋酶打开DNA双螺旋 Protein Synthesis DNA------- mRNA------ protein transcription translation Central Dogma(中心法则) of Molecular ics Transcription One strand of DNA used as a template to make plimentary strand of mRNA Promoter/RNA polymerase/termination site/5’ to 3’ Ways in which RNA & DNA differ: RNA is ss RNA sugar is ribose Base pairing-A-U The structure of a bacterial gene ATG TAA transcript Coding sequence Transcription start site Promoter Ribosome binding site/ translational start (ATG) hisG I. Single gene transcript Translational end Transcriptional terminator