BIOLOGY 1A03 Lecture Notes - Lecture 3: Streptococcal Pharyngitis, Extrachromosomal Dna, Francis Crick

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Colin Gilmour

Document Summary

Two types of nucleic acids: deoxyribonucleic acid (dna) and ribonucleic acid (rna) Plasmids small circular dna molecules, which are circular chromosomes folded in many loops (usually found in bacteria) Plasmids replicate core genome and be transferred (rapid spread of genes for bacterial population) Eukaryotes have large linear chromosomes vs prokaryotes have smaller circular chromosomes. Chromosome organization of double stranded dna. E. coli, the nucleoid has around 100 loops (each has 50kb of negatively. Over 400 bacterial strains have been completely sequenced (2013) E. coli has a circular chromosome carrying all the necessary genes for it to supercoiled dna) Supercoiling preserves double helix structure and compacts dna into small space. Supercoiling for dna is in addition to double helix structure. Also has circular plasmids containing extrachromosomal dna genes for survival in distinct environments. Genomic map represents position of genes on the chromosome. Operon (cluster of genes) involved in metabolism of sugar and lactose.