Chapter 10 Flashcards
Life depends on what three molecules?
DNA, RNA and protein
Traits of DNA replication
very quickly, accurately, and the appropriate time in the life of a cell
How many base pairs in E coli chromosome?
5 million, capable of copying DNA in less than an hour
How many base pairs in human chromosomes?
3.1 billion, takes a few hours to copy DNA
In what direction does DNA proceeds around the bacterial chromosome?
Bidirectionally
What is the leading strand?
DNA pol III attaches to nucleotide in 5’ to 3’ direction as it slides towards the opening of the replication fork
What is the lagging strand?
Synthesizes in 5’ to 3’ direction
requires RNA primers
DNA pol III uses RNA primers to synthesize small DNA fragments
What does DNA pol I do?
removes RNA primers and fills the resulting gap with DNA, covalent bond is still missing
What does DNA ligase do?
catalyzes a phosodiester bond
What is oriC?
origin of chromosomal replication in E coli
What three types of DNA sequences in oriC are functionally significant?
AT-rich region
DnaA boxes
GATC methylation sites
What does DNA helicase do?
separates the two DNA strands by breaking the hydrogen bonds (generates supercoiling ahead of replication fork)
What does DNA topoisomerase do?
travels ahead of the helicase and alleviates supercoils
What do single-strand binding proteins do?
bind to separated DNA strands to keep them apart
In E coli, what protein deals with DNA repair and replication of damaged DNA?
DNA pol II, IV, V
