ch369_ch 17-DNA replication

ch369_ch 17-DNA replication - DNA replication Chapter 17...

Info iconThis preview shows pages 1–15. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

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

Unformatted text preview: DNA replication Chapter 17 Central dogma of molecular biology: Review DNA structure. Review DNA structure. Watson-Crick base pairing: Hydrogen bonding lets A recognize T, G recognizes C. 5 ’ 5’ 3’ 3’ Major and minor grooves in DNA. minor major major groove minor groove Rotate 30 degrees around this axis. When DNA structure was discovered in 1953, it was immediately recognized that DNA could serve as a template for its own replication. “ It has not escaped our notice that the specifc pairing we have postulated immediately suggests a possible copying mechanism For the genetic material.” Initially, 3 different models for DNA replication were considered: “ Semi-conservative ” was shown to be the correct model in 1958, with key experiments being performed by Meselson and Stahl (where density of DNA enriched in 15 N or 14 N nitrogen isotopes was measured before and after replication). New DNA strands are a hybrid containing one parental DNA strand ( blue ) and one newly- synthesized strand ( red ). DNA replication: Circular bacterial DNA caught in the act. DNA is “negatively supercoiled”. DNA topoisomerase is an enzyme that can change the amount of supercoiling in DNA: To change supercoiling, topoisomerase breaks and re-joins the DNA strands . The process requires energy (provided by ATP hydrolysis). Figure 17.03 Action of type I topoisomerase. Mechanism of a Type I Topoisomerase ( Type II topoisomerases break both DNA strands before re-sealing the DNA) Unnumbered, page 534 (1) DNA. Type I topoisomerases temporarily attach the broken DNA strand to a tyrosine, before re-joining the DNA strands again. All living things (eukaryotes, bacteria & archaea) use topoisomerases during their DNA replication process....
View Full Document

This note was uploaded on 08/26/2010 for the course CH 369 taught by Professor Kbrowning during the Spring '07 term at University of Texas.

Page1 / 39

ch369_ch 17-DNA replication - DNA replication Chapter 17...

This preview shows document pages 1 - 15. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online