Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
What does semiconservative replication mean? |
It means that two daughter strands of DNA each contain one strand of the parent DNA |
|
|
What three observations have been made of all DNA polymerases? |
1) Incoming base pairs is selected by complementary base pairing with a template strand 2) Chains grow from the 5' to 3' direction 3) All DNA polymerases require a primer strand to add bases to |
|
|
What is the function of DNA polymerase 1? What s the Klenow fragment? |
DNA Polymerase 1 is an enzyme invlved in prokaryotic DNA elongation and repair. It has 3 activities: Synthesis (5' to 3' polymerase activity), Repair and removal (5' to 3' exonuclease activity) and proof reading (3' to 5' exonuclease activity)
-a subunit of DNA polymerase that contains the 5' to 3' synthesis activity and the 3' to 5' proofreading activity |
|
|
What is the function of DNA polymerase 3? |
DNA polymerase 3 is a prokaryotic DNA elongation and repair enzyme. It is made of 10 subunits which form a sliding clamp that works along the strand. It has a higher processivity that DNA polymerase 1 |
|
|
What is the function of a topoisomerase? A helicase? |
-topoisomerase is an enzyme that changes the topography of DNA molecules by cutting strands allowing the supercoiling to be adjusted and then religating the strands -Unwinds DNA base pairing by hydrolyzing the hydrogen bonds |
|
|
In replication which strand is the leading strand and which is the lagging strand? Which is synthesized continuously, and which is not? |
The 5' to 3' strand is the leading strand, and the 3' to 5' strand is the lagging strand.
The 5' to 3' strand (leading strand) is continuously made, and the 3' to 5' strand (lagging strand) is not |
|
|
How is RNA used in DNA replication? what are Okazaki fragments? |
RNA acts as a primer for the discontinuous replication of DNA of the 3' to 5' (lagging) strand.
Okazaki fragments are pieces of DNA that are replicated on the 3' to 5' strand that will eventually be joined by ligases to make a complete DNA replicate strand |
|
|
Where is E- coli DNA initiated and where is it terminated? |
It is initiated at Ori-C and terminated at the ter site |
|
|
What are the processivities of DNA polymerasees 1 and 3? |
DNA polymerase 1 has low processivities (20 bases before it dissociates) and DNA polymerase 3 has high processivites (5 million bases before it dissociates) |
|
|
Where is DNA found in Eukaryotes? How is DNA packaged? |
Most of the DNA is in the nucleus, a small amount in the mitochondria
DNA is packaged by wrapping around histones |
|
|
What are some contrasts between features of prokaryotic and eukaryotic DNA replication? |
Eukaryotic DNA is much longer, the synthesis is much slower and occurs in accordance with the cell cycle. They also use a lot more DNA polymerase coleecules and begin replication at multiple sites |
|
|
Which DNA polymerase is believed to be responsible for leading strand synthesis and which for lagging strand synthesis in eukaryotes? |
Leading strand synthesis: DNA polymerase delta Lagging strand synthesis: DNA polymerase alpha |
|
|
What proteins are in nucleosomes and why do they bind to DNA? |
they contain large positive histone molecules. They bind to DNA because their positively charges are attracted to DNA's negatively charged phosphate groups |
|
|
What is PCNA, and what role does it play? |
Poliferating Cell Nuclear Antigen is a cyclin that forms a clamp around the template DNA strand to dramatically increase the processivity of DNA polymerase delta |
|
|
What is the arrangement of nucleosomes after DNA replication? how might nucleosomes affect eukaryotic replication? |
After DNA replication, newly synthesized histones are with the daughter strand while the parent strand has the old histones, the affect of this is that it may be why DNA polymerization is so much slower in eukaryotes (cause you take time to synthesize histones too?) |
|
|
What is the name of the model used to describe DNA replication in mitochondria? |
D-Loop Replication |
