Set up Cornell Notes on pg. 5 Topic: 8.3 DNA Replication Essential Question: Explain how DNA serves as its own “template” during replication. 8.3 DNA Replication 2.1 Atoms, Ions, and Molecules Explain how DNA serves as its own “template” during replication. Key Concept: DNA replication copies the genetic information of a cell.

EQ: This is a template (guide to follow)

T A C G T A T G A A A C T G G T T T A G A A T T On the top ¼ of pg. 4: REVIEW 1. What stage of the cell cycle does DNA replication occur? 2. Why is it important that the DNA is replicated before mitosis occurs? 3. Following the base-pairing rules, please complete the two DNA sequences below : T A C G T A T G A A A C T G G T T T A G A A T T

T A C G T A T G A A A C A T G C A T A C T T T G What stage of the cell cycle does DNA replication occur? S stage or Synthesis Why is it important that the DNA is replicated before mitosis? Each cell must have a full set of DNA T A C G T A T G A A A C A T G C A T A C T T T G T G G T T T A G A A T T A C C A A A T C T T A A

Do you know that your cells are dying right now? Connect Do you know that your cells are dying right now? You may live to 100, but most of your cells will have been replaced thousands of times before then Every time that cells divide to produce new cells, DNA must first be copied in a remarkable process of unzipping and zipping by enzymes and other proteins. Mitosis

KEY CONCEPT DNA replication copies the genetic information of a cell.

What does the word replication mean? A copy or reproduction.

DNA Replication copies the genetic information so that we have two identical strands of DNA. complementary original strand new strand Two molecules of DNA What does identical mean???? Exactly the same!

The rules of base pairing direct replication. Remember: What are our base pairing rules? A=T C=G

Enzymes and other proteins do the actual work of replication. 1. The enzyme Helicase “unzips” the double helix (Hydrogen bonds now broken between the bases) “Free-floating” nucleotides form hydrogen bonds with the original or “parent” strand ( acts as our template).

Make a Key: original strand and new strand in 2 different colors Original/Parent strand New “Complementary” Daughter strand nucleotides unzips Helicase a fragment of DNA

2. DNA polymerase (pol-uh-muh-rays) enzymes bond the nucleotides together to “complementary” bases to form the double helix. Complementary = Go together Ex: A-T C-G What do you think they mean by “complementary”?

The DNA Polymerases, add nucleotides only to the 3’ (3 Prime) end of the strand new strand nucleotide 3’ 5’ complementary 5’ 3’

3. Two identical molecules of DNA are formed, each with an original strand and a “complementary” newly formed strand. complementary original strand new strand Two molecules of DNA Why do we call the new “daughter” strand complementary and not identical to the “parent” or original strand?

Because they are not identical! Ex: Where the parent strand has an “A” the daughter strand will have… “T” complementary original strand new strand Two molecules of DNA

Original “parent” strand Complementary original strand new strand new “daughter” strand Original “parent” strand Conserving the original strand = semiconservative

DNA is called semiconservative because one original strand is conserved, and one complementary new strand is made. complementary original strand new strand Two molecules of DNA What does it mean if you “Conserve” something? You save it!

Homework On the back of your DNA Replication picture page please follow your base-pairing rules and complete the unzipped strand of DNA. Follow the color-coding guide if you need to, change the key to meet your color needs

Marshmallow DNA Replication Activity

Replication is fast and accurate. DNA replication starts at many points in eukaryotic chromosomes. There are many origins of replication in eukaryotic chromosomes. DNA polymerases can find and correct errors.

DNA Replication Video