Bio PCR Test

What are VNTRs?

Variable number tandem repeats; non-coding DNA sequences made of adjacent repeat regions with 10-60 base pairs.

What are STRs?

Short tandem repeats; similar to VNTRs but consist of only 2-6 base pairs.

How are VNTRs inherited?

VNTRs are inherited from parents in a Mendelian way.

Why are VNTRs useful in crime investigations?

They can identify individuals based on unique DNA structures that no one else has.

What is the purpose of PCR in crime scene investigation?

To amplify DNA across known VNTR regions for comparison with suspect profiles.

What is the role of restriction endonucleases (REs)?

REs are enzymes that cut DNA at specific palindromic sequences.

What is a restriction site?

A specific short palindromic sequence where restriction endonucleases cut DNA.

How do REs protect bacterial DNA?

Bacterial DNA is methylated at recognition sites, preventing REs from cutting it.

What are the two domains of restriction endonucleases?

A DNA binding domain that recognizes the palindromic sequence and a catalytic domain that cleaves the DNA.

What is Taq polymerase?

A heat-stable DNA polymerase used in PCR that can withstand high temperatures.

What are the three main steps of the PCR cycle?

Denaturation (95°C), Annealing (50°C), and Extension (70°C).

What happens during the denaturation step of PCR?

Double-stranded DNA is melted into single strands at high heat.

What is the function of primers in PCR?

Primers provide starting points for DNA synthesis by binding to target sequences.

What is the significance of the exponential PCR product curve?

The amount of DNA doubles with each cycle, leading to millions of copies from a small amount of starting DNA.

What is a dehydration reaction?

A reaction that synthesizes a polymer from monomers by removing water.

What is a hydrolysis reaction?

A reaction that breaks a covalent bond in a polymer by adding water.

What is the challenge of synthesizing the lagging strand during DNA replication?

DNA polymerase can only build in the 5' to 3' direction, opposite to the movement of the lagging strand.

What are Okazaki fragments?

Short segments of DNA synthesized on the lagging strand during DNA replication.

What is the role of DNA ligase?

DNA ligase seals gaps in the sugar-phosphate backbone, joining Okazaki fragments into a continuous strand.

What is the purpose of using PCR for cloning?

To produce many copies of a DNA fragment that can be inserted into a vector for replication.

What is the function of primase in DNA replication?

Primase synthesizes short RNA primers to provide starting points for DNA polymerase.

What is the role of DNA polymerase III?

It catalyzes the elongation of new DNA strands by adding nucleotides to the 3' end.

What is the function of DNA polymerase I?

It removes RNA primers and replaces them with DNA nucleotides.

How does Taq polymerase differ from regular DNA polymerases?

Taq polymerase is heat-stable and can survive the high temperatures used in PCR.

What is the process of ligation in recombinant DNA technology?

Ligation involves joining DNA fragments together after they have been cut with restriction enzymes.

How is the likelihood of a VNTR profile calculated?

By multiplying the frequencies of each VNTR locus in the general population.

Topiosmerase

is an enzyme that alters the supercoiling of DNA, helping to relieve torsional strain during replication and transcription.

DNA Primase

is an enzyme that synthesizes short RNA primers complementary to a single-stranded DNA template, providing a starting point for DNA replication.

Primer

is a short nucleic acid sequence that provides a starting point for DNA synthesis during replication and PCR.

Helicase

is an enzyme that unwinds and separates the double-stranded DNA during replication, allowing the strands to be copied.

Single Strand Binding Proteins

are proteins that bind to single-stranded DNA during replication to prevent re-annealing and protect the DNA strands from degradation.

Phosphodiester Bond 

is a type of covalent bond that links nucleotides together in a DNA or RNA strand, forming the backbone of the nucleic acid.

Denaturation

is the process in PCR where the double-stranded DNA is heated to separate into two single strands, allowing for subsequent amplification steps.

Primer Annealing

is the stage in PCR where primers bind to their complementary sequences on the single-stranded DNA, allowing for the synthesis of new DNA strands.

Primer Extension 

is the stage in PCR where primers bind to their complementary sequences on the single-stranded DNA, allowing for the synthesis of new DNA strands.