Genome Organization/Function/Replication Bio119 I. The prokaryotic chromosomes A. Kinds of genetic elements in prok and euks 1. Prok and Euk have chromosomes and plasmids B. Prok. chromosome is usually _________________ (Fig. 16.10) C. Usually only have 1 but number can be more if prok. is growing D. Bacteria chromosome can be replicated throughout the cell cycle. E. All prokaryotes are:____________________. F. Majority of prokaryotic chromosome:_______________________. G. Prok. genes usually do not have:______________________ H. An average gene length is about ________________ I. How many genes are there if genome is 6 Mb (6 x 109 bp)? 1. J. Because chromosome is 1 mm long it needs to be: K. This is accomplished by ______________________(Fig 4.31): 1. This is need to make chromosome fit into a small space. 2. DNA gyrase (topoisomerase II) introduces negative supercoiling 3. DNA gyrases are also targets for quinolone type antibiotics 4. Topoisomerase I removes negative supercoiling, which is needed during replication. L. Because supercoiling brings negatively charged phosphates close, M. Further compacting of the chromosome occurs with: II. How does a bacterial cell replicate its chromosome? A. In a ______________________ mode similar to Euks. (Fig. 13.2) 1. Strands separate and each are copied 2. Daughter genome gets: a) _____________________ strand and aGenome Organization/Function/Replication Bio119 b) ____________________________________copy B. Lots of proteins involved in replicating chromosome 1. Table 13.1 C. Initiation of replication (Fig. 13.3): 1. DNA replication starts at an origin of replication, called: 2. DNA binding proteins (______) bind the ________, which causes: 3. __________ binds replication fork with _________and promotes DNA ________________with help of _____________. 4. D. The formation of a replisome (Fig. 13.4): 1. Each replication fork has a leading strand and lagging strand 2. The leading strand is synthesized by: _________________ as a single contiguous molecule starting from an: 3. The lagging strand is synthesized in a discontinuous fashion. E. DNA polymerization: 1. DNA polymerases polymerize: 2. Bacteria have: 3. ______________________ carries out the elongation stage as the replication fork moves forward (Fig. 13.6). 4. Polyermases need: 5. Template must be primed with a nucleotide.Genome Organization/Function/Replication Bio119 F. Polymerization takes place from 5’ to 3’ 1. leading strand is continuous 2. Lagging strand is built in fragments: G. The RNA primer on lagging strand is removed by: 1. Gaps are filled by: H. Termination occurs at the: 1. I. __________________________________ occurs during replication because DNA is helical and must rotate to accommodate the replication fork. 1. Relief of tension and tangling is accomplished: 2. This makes temporary nicks in the DNA allowing it to: J. Separation of daughter chromosomes is accomplished: 1. Causes: 2. DNA can untangle. K. Mistakes also need to be repaired 1. Wrong base pairing can occur: 2. Polymerase error rate is: 3. Errors are corrected by: 4. Mismatch repair system: 5. How does this work (Fig. 13.7): a) b) MutS:Genome Organization/Function/Replication Bio119 c) MutH: d) MutL: e) MutH: f) Exonucleases: g) DNA Pol I: h) DNA ligase: L. If chromosome replication is complete in 40 min how can E. coli grow with a generation time of 20 min? M. Video 1: http://www.youtube.com/watch?v=teV62zrm2P0 N. Video 2: