DNA and the Genome - DNA Replication and PCR Flashcards
1
Q
beginning stages
DNA replication
A
- DNA molecule unwinds
- weak hydrogen bonds break using ATP
- template strands separate to form a Y-shaped replication fork
2
Q
leading strand
DNA replication
A
- a primer attaches to the exposed 3’ end of the template strand
- DNA polymerase aligns free DNA nucleotides to the 3’ end of the primer (according to the base pairing rule)
- DNA polymerase also causes the strong chemical bonds to form between newly added DNA nucleotides forming the completed strand
3
Q
lagging strand
DNA replication
A
- many primers attach to the 3’ end of the template stand as it becomes exposed
- DNA polymerase adds free DNA nucleotides to the 3’ end of the primers (according to the base pairing rule) forming many fragments
- the enzyme ligase joins the fragments together to complete the lagging strand
4
Q
basic requirements for DNA replication
A
- DNA template
- primers
- free DNA nucleotides
- enzymes (DNA polymerase + ligase)
- ATP (energy)
5
Q
requirements for PCR
A
- primers
- supply of DNA nucleotides
- DNA sample
- heat tolerant DNA polymerase (taq)
6
Q
PCR summary
A
- 92 - 98ºC - the two strands of DNA separate (denature)
- 50 - 65ºC - allows primers to bind (anneal) to the target sequence
- 70 - 80ºC - heat tolerant DNA polymerase replicates the target sequence of DNA
7
Q
uses of PCR
A
- forensic science
- disease detection
- phylogenetics
8
Q
amplification
A
increase the number of copies of a DNA molecule by PCR
9
Q
DNA polymerase
A
enzyme required to promote DNA replication
10
Q
ligase
A
enzyme that joins replicated DNA fragments into a complete strand
11
Q
polymerase chain reaction
PCR - what is it?
A
laboratory technique used to create many copies/amplify a peice of DNA
12
Q
primer
A
short sequence of nucleotides needed by DNA polymerase to begin replication of DNA
13
Q
specific target sequence
A
region at the end of a DNA strand complimentary to a primer
