D1.1 DNA replication Flashcards
(23 cards)
What is semi-conservative replication?
Semi-conservative replication is a replication process in which one strand of parental DNA is kept in each new DNA molecule.
Define the term template strand.
The template strand is the original DNA strand that provides the base sequence which acts as a guide for the creation of a complementary new strand.
What does helicase do during DNA replication?
Helicase unwinds the DNA helix and breaks hydrogen bonds between base pairs, exposing the template strands.
What does the enzyme DNA polymerase do?
DNA polymerase is the enzyme that links nucleotides together to form a new DNA strand using the template strand.
What is the significance of keeping one original DNA strand?
Keeping one original DNA strand ensures genetic continuity and accuracy between generations of cells.
What happens when cytosine is exposed on the template strand?
When cytosine is exposed on the template strand, a guanine nucleotide is added to the new strand.
Define complementary base pairing.
Complementary base pairing is the specific pairing of adenine with thymine, and cytosine with guanine, in DNA.
Name the type of bond used to join one nucleotide to the adjacent nucleotide.
Phosphodiester bonds are used to join together adjacent nucleotide bases.
What is gel electrophoresis?
Gel electrophoresis is a technique used to separate DNA, RNA, or proteins based on their size and charge.
Define the term anode in the context of gel electrophoresis.
Anode is the positive pole towards which negatively charged DNA molecules move during electrophoresis.
What is the purpose of PCR?
The purpose of PCR is to amplify specific DNA or RNA sequences, producing large quantities for analysis.
What is the function of Taq polymerase.
Taq polymerase is an enzyme used in PCR that remains stable at high temperatures and synthesizes new DNA strands.
What happens during the denaturation stage of PCR?
During denaturation, the DNA is heated to 95°C, breaking hydrogen bonds between DNA strands, causing the double strands to separate.
What is the role of primers in PCR?
Primers bind to specific sections of DNA to initiate the synthesis of new DNA strands.
What is the role of restriction enzymes in preparing DNA for gel electrophoresis?
Restriction enzymes cut DNA into fragments before separation in gel electrophoresis.
Define the term “annealing” in PCR.
Annealing is the stage in PCR where the temperature is lowered to allow primers to bind to single-stranded DNA.
What is DNA profiling?
DNA profiling is a technique used to identify individuals based on unique patterns in their DNA.
Define VNTRs.
VNTRs (Variable Number Tandem Repeats) are short, non-coding regions of DNA that vary between individuals.
What is the role of restriction endonucleases in DNA profiling?
Restriction endonucleases cut DNA into fragments that can be separated by gel electrophoresis in DNA profiling.
What must be done to DNA samples before they can be analysed in gel electrophoresis?
DNA samples must be amplified using PCR before they can be analysed in gel electrophoresis.
What is the significance of fluorescent probes in DNA profiling?
Fluorescent probes bind to specific DNA sequences and make the DNA fragments visible under UV light in DNA profiling.
Define “contamination” in the context of forensic DNA profiling.
Contamination refers to the accidental introduction of foreign DNA into a sample, potentially leading to incorrect results.
What increases the reliability of DNA profiling in forensic investigations?
Increasing the number of VNTR markers being compared increases the reliability of DNA profiling in forensic investigations.
