December 6, 2010 DNA Replication

1. Draw a segment of DNA and label the following: Warmup (12/6): Answer the following in the warmup section of your lab book. (Write the date!) 1. Draw a segment of DNA and label the following: Sugar (deoxyribose) Phosphate Each of the 4 base pairs What is a nucleosome? What does it allow DNA to do? Suppose one strand of the DNA molecule has a base pair seqence of ACTTGA. What is the base pair sequence of the strand it binds to (complementary strand)?

Write the complementary DNA strand for each of these DNA strands: GAATTACA CCAATTAG ATAGACAG CCAGTACA DNA CTTAATGT GGTTAATC TATCTGTC GGTCATGT

A 3-D Model of DNA

NUCLEOTIDES Made up of: A phosphate group 5 carbon sugar Nitrogenous Base (nitrogen containing)

Each of the 96 columns represents one DNA sequ Each of the 96 columns represents one DNA sequence. A different colored dye attached to each of the four nucleotides ence. A different colored dye attached to each of the four nucleotides.

Go over answers to 12-1 worksheet. Let’s take a look at how DNA replicates! When does this happen? Where does this happen? Why does this happen? What does DNA do?

Watch this… Video overview of DNA replication http://www.dnatube.com/video/365/DNA-Replication

DNA Tutorial http://learn.genetics.utah.edu/content/begin/dna/

DNA Replication (youtube.com movie) The act of making an exact copy of DNA DNA is one of the few molecules on Earth that has this ability Important to pass the information on to daughter cells! What phase of the cell cycle does this happen?

DNA Replication The structure of DNA lends itself to replication Enzymes “unzip” DNA hydrogen bonds linking base pairs DNA Polymerase is the main enzyme that helps build the new DNA strand Each side of DNA serves as a template for the new DNA strand. In prokaryotes this happens at one point In eukaryotes this happens at many points along the DNA

DNA Replication To speed up the replication process, DNA opens up at many sites at once. These sites are called replication forks. One strand of the DNA (leading strand) is replicated one base at a time continuously, but the other strand (lagging strand) is put together in short, non-continuous fragments. http://www.contexo.info/DNA_Basics/replication%20move.htm

Semi-Conservative Replication Each strand of the original molecule acts as a template for the synthesis of a new complementary DNA molecule New strands are ½ new and ½ old

Examples of DNA Replication

DNA replicates to pass on info to daughter cells, but what DNA’s higher purpose? Central Dogma of Molecular Biology DNA serves as the template to make RNA. RNA, in turn, serves as the source of information to make proteins http://library.thinkquest.org/C0122429/intro/genetics.htm

What does DNA do? DNA is the stuff that ___________ are made of. A _____________ is a location on a chromosome. Each gene codes for a _________ which serve many important purposes in living things (structural purposes, enzymes, hormones, etc).

What is a protein? http://learn.genetics.utah.edu/content/begin/dna/

Homework DNA Replication and Cartoon worksheet