DNA Replication Flashcards
RNA Primer
a short segment of RNA used to initiate the synthesis of a new strand of DNA during replication
DNA Polymerase I
an enzyme that removes RNA primers and replaces them with DNA
What did Meselson and Stahl discover?
DNA replication is semi-conservative; each new strand contains one old and one new strand
Semi-conservative model
- the two strands of the parental molecule separate
- each function as a template for the synthesis of a new complementary strand
Allele
a variation of a gene
Topoisomerase
relieves the “overwinding” strain ahead of replication forks by breaking, swivelling, and rejoining DNA strands
Purine structure
double ringed
e.g. adenine and guanine
Ligase
joins the end of DNA that make up the Okazaki fragments
Replication bubble
an unwound and open region of a DNA helix where DNA replication occurs
DNA Polymerase III
after seeing the RNA primer, it synthesizes the leading strand
What is adenine (A) paired with?
thymine (T)
What is the second step of DNA replication?
a new complementary strand is added
Single-stranded binding proteins (SSBs)
stops the two separated parent strands from annealing
Annealing
recombine DNA in the double-stranded form following separation by heat
Okazaki fragment
small fragments of DNA produced on the lagging strand during DNA replication, later joined by DNA ligase to form a complete strand
Pyrimidine structure
single ring
e.g. cytosine, thymine, uracil
Helicase
unwinds DNA helix
What did Hershey and Chase discover?
DNA was the genetic material; radioactively on viruses and proteins
What bonds hold nucleotides together?
phosphodiester bonds
Replication origin
specific sequence of DNA where DNA synthesis begins
Nucleotide structure
- 5 carbon sugar
- phosphate group
- nitrogenous base
What is guanine (G) paired with?
cytosine (C)
What is the first step of DNA replication?
partial unwinding of the double helix
Deoxyribose
a five-carbon sugar that is a component of DNA nucleotides
