Chapter 7 Part A - DNA Replication PDF

Chapter 7 Part A I. DNA Review Please watch the 4 videos located in D2L. They are listed as DNA Structure Videos. This is a review of what you should already know from your Bio prerequisite class. You need to know all the material from the video (except phosphodiester bond; you don't need to know...

Chapter 7 Part A I. DNA Review Please watch the 4 videos located in D2L. They are listed as DNA Structure Videos. This is a review of what you should already know from your Bio prerequisite class. You need to know all the material from the video (except phosphodiester bond; you don't need to know that) Don't forget to maximize the video screen, so that you can actually see it. \*A note about the 5' and 3'. The carbons of the sugar are numbered 1' through 5'. The ' symbol is pronounced prime. The prime is there to tell us that the carbons are part of a sugar molecule. \*\*Antiparallel mean that the 2 strands are parallel to each other, but they run in opposite directions. II\. RNA review The following 2 pictures demonstrates the differences between RNA & DNA. Please note the \# of strands, the sugar, & that uracil replaces thymine for the bases.  Please watch the following video on YouTube: III\. DNA replication A. Making an exact copy of the DNA (necessary for cell division) 1\. DNA replication is \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. B. Requirements for DNA replication 1\. Enzymes 2\. DNA template 3\. dNTPs (A, T, C, & G) a\. d = deoxyribose b\. N = nucleoside (sugar & nitrogenous base) c\. TP = triphosphate (3 phosphates)  Notice that the nucleotides begin with 3 phosphates. When the nucleotide is added to the growing DNA polymer, 2 phosphates are removed. This releases energy, which is used for the anabolic synthesis of DNA. (Remember that anabolic reactions require energy). It is very similar to how ATP works, except we are removing 2 phosphates instead of 1. Also see **Figure 7.6** on page 180 We will now discuss the steps of DNA replication. Each step is catalyzed by an enzyme. IV\. Steps of DNA replication  From this point on, we will only study one replication fork. Everything that is happening at 1 fork is simultaneously happening at the other fork. B. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 1\. Acts like a zipper at the fork to unzip the DNA double helix 2\. Unwinds and separates the DNA strands  In this video, please watch as the helicase enzyme unzips the DNA: You only need to watch the 1^st^ 20 seconds of the video. C. Gyrase (also called Topoisomerase type 2) D. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 1\. This enzyme synthesizes a primer - It tells the DNA Polymerase III where to begin - Why is it made of RNA? No one really knows. There are a few hypotheses, but nothing definitive. Please watch the video in D2Lis listed as DNA Replication Video 1 3\. Leading strand Please watch the DNA Replication Videos \# 1-3 4\. Lagging strand Please watch DNA Replication Video \# 4 F. DNA Polymerase I G. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Please watch DNA Replication Video \# 5 Also, please watch the following YouTube video: There is a helpful table in your book that defines the different components of the replication process. **Table 7.1** on page 181 V. DNA replication is bidirectional around the chromosome. A. Remember that the replication bubble actually has 2 forks. So, the replication process is happening twice. It is happening at the left fork, with the DNA being unzipped towards the left. It is also simultaneously happening at the right fork, with the DNA on that side being unzipped towards the right. This is called bidirectional, because the replication process is happening simultaneously in 2 directions. Please see **Figure 7.5** on page 179