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20 Cards in this Set
- Front
- Back
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What is the purpose of DNA fingerprinting? |
To identify the source of unknown DNA samples.
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How is DNA fingerprinting carried out?
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Use enzyme to generate DNA fragments
Electrophoresis gel analysis Southern blot analysis SLP or MLP probe |
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What restriction enzymes are commonly used in forensics labs to generate DNA fragments?
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Hae III (GGCC)
Hinf I (G'ANTC) |
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What determines the size of DNA fragments in DNA fingerprinting?
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The distance between restriction enzyme recognition sites on individual alleles.
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What is the formula to estimate the number of times a restriction enzyme cleaves a double stranded DNA?
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4^N= Expected occurrence of restriction site
N= number of bases in a restriction enzyme recognition site. |
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What are alleles and how do they allow us to identify individual DNA fingerprints?
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1. Alleles are alternate forms of genes that exist on chromosomal a chromosomal locus
2. One allele from father and one from mother 3. Differences in individuals base sequences as expressed in alleles compose an individuals genotype |
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How do we run Restriction Fragment Length Polymorphism analysis?
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Enzymes cut different length fragments based on individual combination of DNA. Enzymes cut at specific recognition sites (GGCC). The pattern of these fragments creates a DNA fingerprint.
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How are probes used in DNA fingerprinting?
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Probes are radioactively tagged. They bond to specific sequences of DNA and allow is to detect the DNA segments on a Southern blot.
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What types of probes are used in southern blot analysis?
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Single Locus Probes (SLP): locate single segments of DNA at specific sites on single chromosomes.
Multiple Locus Probes (MLP): locate multiple repetitive segments on many chromosomes. Generally yields 20-30 bands. |
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Which type of probe is most commonly used in Forensics Labs and why?
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Single Locus Probes are most commonly used because they require less DNA, and are also cheaper. Since individuals can share any given SLP, commonly more than one SLP is run at a time.
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What is southern blot analysis used for in forensics labs?
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Analysis of Restriction Fragment Length Polymorphisms in order to obtain a DNA fingerprint.
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What are the steps in DNA fingerprinting?
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1. Electrophoresis
2. Treat gel with HCl and NaOH 3. Transfer DNA to treated nylon 4. Probe DNA fragmetns 5. Expose membrane to X-ray |
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What does HCl do in a southern blot? |
HCl treatment introduces apurinic sites in DNA that make phosphoiester bonds a these sties likely
They nick DNA |
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What does NaOH do in a southern blot?
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NaOH treatment disrupts interstrand hydrogen bonds between base pairs. It makes double stranded DNA into singe stranded DNA
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How is DNA transferred to they nylon in a southern blot?
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Via capillary action
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How do DNA probes work in a southern blot?
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Probes are made of DNA fragments with complimentary base sequences that are labeled with radioactive isotopes
They hybridize to the DNA strands where compatible (at restriction enzyme sties) by bonding with the singe stranded DNA The small amount of DNA that is complimentary to the probe with fluoresce |
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What is the Baculavirus Expression Vector System?
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The production of proteins with biological activity that are similar to natural proteins using insect cells
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In what markets is BEVS commonly used?
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diagnostic and therapeutic markets
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What are the two advantages of BEVS? |
It produces large quantities of functional recombinant proteins
Insects (unlike bacteria and yeast) can both post-transnationally modify recombinant proteins and has a simple glycosylation system |
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Why are Sf9 cells popular?
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Sf9 cells have a faster growth rate and can achieve higher density than other isolated insect cell lines.
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