Structure and Replication of DNA Unit 1 Flashcards
To which carbon attachment prints do bases and phosphates attach in a DNA nucleotide ?
Carbon 1 and 5
What name is given to the backbone of a DNA strand formed from deoxyribose sugar and phosphate ?
Sugar-phosphate backbone
What type of bonds form between bases on two complimentary strands ?
Hydrogen bonds
What term is used to describe the fact that the two stands of DNA run in opposite directions to each other ?
Anti-parallel
Name the two ends of one DNA strand
3’ and 5’ end
What name is given to the strand that is found on the left hand side on a DNA strand that runs from 3’ to 5’ ?
Leading strand
What name is given to the arrangement of the two strands of DNA ?
Double helix
What name is given to the short sequence of nucleotides that attach to the 3’ end of the parental strand about to be replicated ?
Primer
What name is given to the enzyme needed to replicate the strands during DNA replication ?
DNA polymerase
How is the replication of the leading strand described because it is replicated without any interruptions ?
Continuous
What name is given to the strand opposite the leading strand ?
Lagging strand
How is replication of the lagging strand described because it is replicated in fragments ?
Discontinuous
Name the enzyme needed to join the fragments together in the lagging strand ?
Ligase
Name 5 requirements of DNA replication ?
- DNA template strand
- ATP
- DNA nucleotides
- Primers
- Enzymes (DNA polymerase and Ligase)
What name is given to the technique that can be used to create many copies of a piece of DNA outside of the body ?
Polymerase Chain Reaction (PCR)
What word is used to describe the fact that you are making multiple copies of a piece of DNA in PCR ?
Amplification
Name 3 uses of amplified DNA produced through PCR
- Forensic (crime scene investigation)
- Medical (genetic disorder)
- Parernity disputes
What is a nucleotide made of ?
- Deoxyribose sugar
- Phosphate
- Organic base
What does DNA polymerase control ?
The sugar-phosphate bonding between nucleotides on the new DNA strand
What is needed to initiate DNA Replication ?
A primer
What is a primer ?
A short strand of complementary nucleotides formed at the 3’ end of the parental DNA strand
What end does DNA polymerase add nucleotides to ?
3’ end of a growing strand
What joins the fragments together ?
Ligase
What is PCR ?
PCR is a technique that replicates short sections of DNA quickly outside of the body
Amplification of DNA involves what ?
The use of primers
What does DNA profiling allow ?
The identification of individuals by comparing regions of the genome with highly variable number of repetitive sequences of DNA
What are the repeating units called that make up a molecule of DNA ?
Nucleotides
Explain why the lagging strand has to be copied in fragments
Because the relocated strand is discontinuous and nucleotides can only be added to 3’ end of a primer
What is the function of DNA polymerase in DNA replication ?
Bonds nucleotides into the backbone of a new DNA strand
What is the function of Ligase in DNA replication ?
Joins fragments of DNA together on the lagging strand
Name 3 uses of DNA amplified through PCR
- Medical
- Forensic
- Paternity Disputes
1st step of PCR
Mixture heated to 92-98°C to break hydrogen bonds and allow strands to separate (melting)
2nd step of PCR
Temperature reduced to 50-60°C to allow primers to attach (annealling)
3rd step of PCR
Temperature increased to 70-80°C. Heat-tolerant DNA polymerase adds nucleotides into DNA strands (extending)
4th step of PCR
This process is repeated many times to amplify DNA
