bioc441 - 2008Problemset3

bioc441 - 2008Problemset3 - Biochemistry 441 Ted Young...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Biochemistry 441 Homework set #3: DNA replication and repair Ted Young Page1/2 1. Short, newly synthesized pieces of DNA were identified by Okazaki only after denaturing the DNA and centrifuging it to separate molecules of different sizes. Why was it necessary to denature the DNA? 2. A very important experiment was done to prove that DNA and RNA were covalently linked in Okazaki fragments. Radioactive Okazaki fragments were made in vivo by adding 32 P-dNTP (labeled in the α -position ) to E. coli which had been treated (permeabilized) to allow dNTP to diffuse into the cells and be used as precursors for DNA synthesis. After purifying the Okazaki fragments they were treated with OH - to hydrolyze the suspected RNA portion. Acid insoluble material was removed and the resulting nucleotides were separated by chromatography and electrophoresis. Four radioactive spots were detected after autoradiography. What were they? It will help to draw out a diagram of the nucleotides that were used in the experiment, and what happens to the label in the α -position of dNTP when the phosphodiester bond is hydrolyzed. Are the labeled nucleotides ribo- or deoxyribonucleotides? Did addition of deoxyribonucleotides by Pol III begin after a particular base in the template? How
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

bioc441 - 2008Problemset3 - Biochemistry 441 Ted Young...

This preview shows document pages 1 - 2. Sign up to view the full document.

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