Unit 1.2 - Structure + Replication Of DNA Flashcards
1
Q
Describe the structure of DNA
A
- Made up of nucleotides (deoxyribose sugar, phosphate and base)
- Sugar phosphate backbone
- Base pairing ( A+T and G+C)
- Base pairs held together by hydrogen bonds
- Double stranded anti parallel structure
- Deoxyribose at 3’ end and phosphate at 5’ ends of each strand
- Forming a double helix
2
Q
What happened prior to cell division?
A
DNA is replicated by a DNA polymerase is DNA polymerase needs primers to start replication
3
Q
What is a primer?
A
A short strand of nucleotides which binds to the three prime end of the templates DNA strand allowing polymerase to add DNA nucleotides
4
Q
What are some practical applications of PCR?
A
DNA can be amplified to help solve crimes, settle paternity suits and diagnose genetic disorders
5
Q
What is PCR?
A
PCR amplifies DNA using complimentary primers for specific target sequences
6
Q
Describe DNA replication
A
- DNA is unwound and hydrogen bonds between bases are broken to form two template strands
- DNA polymerase adds DNA nucleotides using complimentary base pairing to the deoxyribose three prime end of the new DNA strand which is forming
- DNA polymerase can only add DNA nucleotides in at five prime to 3 prime direction
- Resulting in the leading Strand being replicated continuously and the lagging strand is being replicated in fragments
- Fragments of DNA are joined together by ligand
7
Q
Describe the amplification of DNA sequences in PCR
A
- DNA is heated to between 92 and 98° to separate the complimentary strand
- It’s them cooled to between 50 and 65° to allow primers to bind to specific target sequences
- It is then heated to between 70 and 80° for heat tolerant DNA polyamory is to replicate the region of DNA
- Repeated cycles of heating and cooling amplify the region of DNA