Theory
Friedrich Miescher discover what substance?
Nuclein (We now call this DNA!)
What are the 3 stages of DNA replication?
Initiation
Elongation
Termination
What are the four bases in DNA?
adenine (A), cytosine (C), guanine (G), and thymine (T)
What is the role of Helicase
Unzips DNA - Breaks the hydrogen bonds
What isotopes was used in the E.coli experiment by Meselson and Stahl
15N (heavy) and 14N (light)
Name one example of an error that can occur during DNA replication
Mismatched base pairs or strand slippage
True or False... Prokaryotic cells have 2 or more chromosomes
False. They have 1 chromosome
What protein is responsible for unwinding DNA
Initiator proteins (DNA gyrase)
In RNA, ___ is paired with adenine instead of thymine
Uracil
What would happen if we did not have single strand binding proteins?
Could not keep DNA strands apart
DNA strands are always __ to each other
antiparallel
_____ joins the ends of Okazaki fragments in the lagging strand synthesis
DNA Ligase
A chicken's DNA is made of 28% adenine, and 22% cytosine... Using Chargaff’s rules, what are the most likely percentage of guanine and thymine in the chicken DNA sample.
Guanine 22%, thymine 28%
What is the complimentary strand of the following template 5’-CTGATGAA-3’
3’-GACTACTT-5’
What is the difference between the chromosome shape in prokaryotic cells and eukaryotic cells
Prokaryotic cells have circular chromosomes while eukaryotic has linear.
What two proteins proofread the DNA Strands
DNA polymerase I and II have proofreading abilities
Why is the dispersive model of DNA incorrect?
Every round of replication would result in hybrids (Light/Heavy).This is not true and the E.coli experiment showed that the hybrids eventually separate in subsequent generations creating brand new synthesized DNA.
Explain why the lagging strand is said to travel in a "dis-continuous" fashion
It moves away from the replication fork meaning as the helicase unzips your DNA, primers have to go back and re-attach to the template strand
What is the difference between a replication bubble and a replication fork?
Bubble forms when helicase separates DNA templates (initiates replication), where as the fork is formed within the bubble
Where does DNA Polymerase III add nucleotides on a DNA strand?
Can ONLY add nucleotides to the 3' end of an existing DNA strand using free -OH