Chapter 10 Flashcards
What is supercoiled DNA?
DNA that is more compact than its relaxed counterpart
Underwound DNA is (negatively or positively) supercoiled?
Negatively
Overwound DNA is (negatively or positively) supercoiled?
Positively
What is the purpose of underwound DNA?
To allow chromosomes to fit within the nucleus
Type I topisomerases do what?
Change the supercoiled state by creating a transient break in one strand of the duplex
Type II topisomerases do what?
Make a transient break in both strands of the DNA duplex, can also tie a DNA molecule into knots or untie DNA knots
Define: Transient
Lasting for a short time
Define: Denaturation
Ability to separate into its separate components
Thermal denaturation
DNA melting
How can you monitor thermal denaturation?
The increase in absorbance of UV light by dissolved DNA
Higher the GC content (higher or lower) the melting temp?
Higher
Higher AT (higher or lower) the melting temp?
Lower
Define: Renaturation
When single-stranded DNA molecules are capable of reassociating
Reannealing is also known as
Renaturation
What are the 3 broad classes of DNA sequences?
- highly repeated fraction
- moderately repeated fraction
- nonrepeated fraction
Highly repeated DNA sequences represent how much total DNA?
1-10%