Biology 1001A Lecture Notes - Lecture 6: Dna Polymerase, Telomerase, Replisome
Document Summary
Components: 5-carbon deoxyribose sugar, nitrogenous bases, and phosphate groups linked by covalent bonds. Two strands of dna held together in a double helix by hydrogen bonds between the nitrogenous bases and run antiparallel to each other. Purine-pyrimidine complimentary base pairing: adenine bonds to thymine, guanine bonds to cytosine. Each strand has a distinct 3" and 5" end (referring to a carbon atom in the deoxyribose sugar) 3" has a free hydroxyl (oh) group. A replisome includes all the enzymes involved in dna replication. Dna is read 3" to 5" and replicated 5" to 3"; dna polymerase can only extend the 3" end leading strand is replicated continuously, lagging strand is replicated discontinuously. Circular prokaryotic dna creates two replication forks (a replication bubble) that travel in opposite directions -> bi-directional. Linear eukaryotic dna is often much larger, so several origins are fired simultaneously from which replication bubbles begin constructing new.