Lecture.12.Fall.2013

Eukaryotic replication is much slower than bacterial

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: cation: Linear eukaryotic replication • Small genomes like those in bacteria and viruses can be replicated efficiently from one origin of replication • However, larger eukaryotic genomes require multiple origins of replication. • Eukaryotic replication is much slower than bacterial replication: • 500-5000 nt/minute Modes of replication: Linear eukaryotic replication • Starting from a single origin, it would take over 7 days to replicate a human chromosome • HUMAN GENOME IS NOT CIRCULAR Actually takes minutes to hours because replication takes place from several origins • UNITS OF REPLICATION A typical eukaryotic replicon, a region of the genome replicated from one origin, is 20,000-300,000 bp long. Modes of replication: Linear DNA DONT ALWAYS START SIMULTEANOUS, MORE OR LESS SIMUL Requirements for Replication • Replication includes many components: • A template consisting of single-stranded DNA • dNTPs (deoxyribonucleoside triphosphates) ALL 4 Requirements for Replication • Replication includes many components: • Enzymes and other proteins THAT CARRY OUT SYNTHESIS • “read” the template • assemble the substrates into a DNA molecule New DNA is synthesized from dNTPs RELEASED AS NRG, CAN BE USED BY ENZ TO DO WORK DNA synthesis always proceeds 5’-to-3’ NEW BASE MUST BE ADDED LAGGING STRAND REPLICATED IN FRAG AND IS ASSEM IN PIECES ALWAYS HAVE LEADING AND LAGGING STRAND DNA synthesis is continuous on one template strand and discontinuous on...
View Full Document

Ask a homework question - tutors are online