Lab 9 DNA Replication
1. DNA replication is a semi-conservative process. This means that the: two resulting DNA double helices produced at
the end of DNA replication each contain one original (old) strand of DNA and one newly synthesized strand of DNA.
2. Each original DNA strand: is the template (directions) for building a new strand of DNA based on nucleotide base
pair complementarity.
3. Where does copying occur: the replication fork(y shaped structure where new DNA strands are synthesized by a
multi enzyme complex
4. First step of DNA replication: separating the strands by an enzyme called helicase
5. Hellicase: breaks the hydrogen bonds of complementary nucleotide base pairs, allowing for the DNA helix to be
unwound (opened up).
6. What are seperated strands called: 3 prime and 5 prime
7. Topoisomerase: Enzyme that functions in DNA replication, helping to relieve strain in the double helix ahead of
the replication fork.
8. replication fork: A Y-shaped region on a replicating DNA molecule where new strands are growing.
9. By breaking the hydrogen bonds between DNA nucleotide base pairs, heli- case provides the enzyme: primase with
access to begin building primers, short stretches of RNA nucleotides that are complementary to the open DNA strands.
10.Why are these primers a nessasary component to the DNA replication: - DNA polymerase III will only begin adding
DNA nucleotides to a region of nucleotides that already are bound to the DNA template to be read.
11.DNA polymerase I: builds two new strands of DNA
12.Building the leading strand only requires one: RNA primer and DNA synthe- sis is continuous.
13.Building the lagging strand requires many: RNA primers because of the 5'
-->3' synthesis requirement
14.Okazaki DNA fragment: are eventually joined together by first removing the RNA primers, replacing the RNA
primers with DNA (DNA Polymerase III), and then joining the breaks in the backbone of the Okazaki fragments by
DNA ligase.
15.Where does DNA replication occur? (eukaryotes): nucleus
16.When does DNA replication occur?: S phase of interphase
17.DNA polymerase: Builder this enzyme replicates DNA molecules to actually build a new strand of DNA
18.Primers: so DNA polymerase can figure out when to start and end work
19.Ligase: helps glue together DNA fragments
20.Process of DNA replication: 1. Starts at the origin helicase comes in and unwinds DNA
2. SSB proteins bind to DNA strands to keep the separated
1/
4
1. DNA replication is a semi-conservative process. This means that the: two resulting DNA double helices produced at
the end of DNA replication each contain one original (old) strand of DNA and one newly synthesized strand of DNA.
2. Each original DNA strand: is the template (directions) for building a new strand of DNA based on nucleotide base
pair complementarity.
3. Where does copying occur: the replication fork(y shaped structure where new DNA strands are synthesized by a
multi enzyme complex
4. First step of DNA replication: separating the strands by an enzyme called helicase
5. Hellicase: breaks the hydrogen bonds of complementary nucleotide base pairs, allowing for the DNA helix to be
unwound (opened up).
6. What are seperated strands called: 3 prime and 5 prime
7. Topoisomerase: Enzyme that functions in DNA replication, helping to relieve strain in the double helix ahead of
the replication fork.
8. replication fork: A Y-shaped region on a replicating DNA molecule where new strands are growing.
9. By breaking the hydrogen bonds between DNA nucleotide base pairs, heli- case provides the enzyme: primase with
access to begin building primers, short stretches of RNA nucleotides that are complementary to the open DNA strands.
10.Why are these primers a nessasary component to the DNA replication: - DNA polymerase III will only begin adding
DNA nucleotides to a region of nucleotides that already are bound to the DNA template to be read.
11.DNA polymerase I: builds two new strands of DNA
12.Building the leading strand only requires one: RNA primer and DNA synthe- sis is continuous.
13.Building the lagging strand requires many: RNA primers because of the 5'
-->3' synthesis requirement
14.Okazaki DNA fragment: are eventually joined together by first removing the RNA primers, replacing the RNA
primers with DNA (DNA Polymerase III), and then joining the breaks in the backbone of the Okazaki fragments by
DNA ligase.
15.Where does DNA replication occur? (eukaryotes): nucleus
16.When does DNA replication occur?: S phase of interphase
17.DNA polymerase: Builder this enzyme replicates DNA molecules to actually build a new strand of DNA
18.Primers: so DNA polymerase can figure out when to start and end work
19.Ligase: helps glue together DNA fragments
20.Process of DNA replication: 1. Starts at the origin helicase comes in and unwinds DNA
2. SSB proteins bind to DNA strands to keep the separated
1/
4
