1.2 Structure And Replication Of DNA Flashcards
Describe the structures in a DNA molecule
Dna is double stranded
Dna bases Cytosine and guanine are complementry and adenine and thymine are complementry
Dna strands are anti parcel
There are hygogen bonds between the bases
Describe the structure of a Nucleotide
Phosphate
Deoxyribose suger
Base
Held together by strong covalent bonds
State the base pairing rule
Bases are complementary to each other
Describe the proccess of DNA replication stage 1
DNA double helix is unwound and unzipped and the hydrogen bondsbreteen bases are broken
Compare the Leading and Lagging strand
The leading strand is made continously
The lagging strand is replicated in fragments
State the function of PCR
Is a technique used for amplification of dna.
State the ingredients needed for PCR
Dna
Complementry primers
Thermal cycler
Heat tolerant polymerase
Supply of nucleotides
Name the 3 stages of PCR
Denaturation
Annealing
Elongation
State the practical applications of PCR
Solving crime /Forensics
Diagnosing genetic disorders
Paternity tests
Describe the proccess of DNA replication stage 2
DNA polymerase needs primers to start replication. A primer is a short strand of nucleotides that bind to the 3 prime end of the DNA strand, allowing polymerase to add DNA nucleotides
Describe the proccess of DNA replication stage 3
The lagging strand is replicated in fragments because nucleotides can not be added to the posphate 5’ end because DNA polymerase can only add DNA nucleotides in a 3’ to 5- end
Describe the proccess of DNA replication stage 4
The fragments are then sealed together by an enzyme called ligase
List thr requirements for DNA replication
DNA
Primers
Ligase
Polymerase
Free nucleotides
State the temperature name and what happens in stage 1 of PCR
Denaturation
92 -98 °
DNA is heated, which separates original DNA strands by breaking hydrogen bonds between strands
State the temperature name and what happens in stage 2 of PCR
Annealing
50 - 65°
Allows primers to bind to target sequence
