Module 1
What occurs during the S Phase of the Cell Cycle?
DNA Synthesis
What phase does the separation of sister chromatids into individual chromosomes occur?
Anaphase
What minimizes the stress caused by the unwinding of DNA during DNA replication?
What is stated by the semi-conservative theory?
Each replicated DNA strand contains 1 parent and 1 daughter strand
On what strands do continuous and discontinuous replication occur respectively?
Leading/Bottom strand, Lagging/Top Strand
What two events occur during the M Phase?
Mitosis and Cytokinesis
In what phase are spindle microtubules broken down?
Telophase
In what organisms can there only be one origin of replication in DNA replication?
Prokaryotes
List the three theories of DNA replication
Conservative, Semi-Conservative, Dispersive
In what direction does the 3' end of the continuous strand build towards?
Towards the replication fork
What takes place during Metaphase?
Chromosomes align at the center of the cell
What are the stages of Mitosis in order?
Prophase, Prometaphase, Metaphase, Anaphase and Telophase
Match each picture to it's corresponding DNA replication theory
Go to Image C4R3
What is the name for the separated fragments of DNA built off the lagging strand?
Okazaki Fragments
Where are kinetochores located and what purpose do they serve?
They are regions on the centromeres, are specialized protein structures that attach to spindles fibres
Name the 3 major checkpoints in the cell cycle.
G2 Checkpoint, Metaphase Checkpoint, G1 Checkpoint.
What is the purpose of DNA Ligase in DNA replication?
Attaches Okazaki Fragments
Why does the lagging strand replicate DNA in a discontinuous fashion?
It must build away from the replication fork since the parent strand it is building off of is in a 3' to 5' direction, and DNA polymerase can only add nucleotides to the 3' end of the strand.
List the order of Phases Mitosis, G1, Cytokinesis, G2, S phases and explain what occurs in each of these stages. Begin at G1.
G1, S, G2, Mitosis, Cytokinesis.
G1 and G2 are gap growth phases, prepare cell for division
DNA synthesis occurs in S Phase
Mitosis, the cell undergoes division, stays intact
Cytokinesis, cell breaks apart into two identical sister cells.
How does cytokinesis in animal cells differ from cytokinesis in plant cells?
In animal cells a contractile ring forms along the middle of the cell, causing a cleavage furrow that separates the cell.
In plant cells, the cell walls fuse (cell plate).
Discuss how Meselson and Stahl's experiment proved the Semi-Conservative theory of DNA replication
First-generation harvested in 14N showed an intermediate band between DNA harvested only in 15N vs 14N. 2 generation replication showed band at 14N. One gen of cultivation led to one 14N daughter and one 15N parent. Second-gen cultivation led to 14N parent and 14N daughter.
What is the purpose of DNA Polymerase in DNA replication? (Bonus 500 for discussing purpose of DNA Polymerase I and DNA Polymerase III)
Extends RNA Primers by adding base pairs, proof reads for errors.
DNA Polymerase I removes RNA Primer
DNA Polymerase III performs most elongation