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11 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the spectrophotometry absorbance wavelength (in nm) for nucleic acids? for proteins?
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Nucleic acids - 260nm
Proteins - 280nm |
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What does the A260/A280 ratio estimate when detecting nucleic acids via spectrophotometry?
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A260/A280 ratio estimates purity (ie - nucleic acid concentration to protein concentration ratio)
1.8–2.0 = high purity <1.8 = contamination with protein or phenol |
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Difference between mutation and polymorphism?
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both are change in DNA sequence.
mutation has NEGATIVE effect on phenotype polymorphism is not negative effect if phenotype is not certain, call it a variant |
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PCR inhibitors? (list)
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Detergents, phenol, heparin, heme, dyes, CSF, urine, sputum, paraffin
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One substance used to reduce contamination in PCR?
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Uracil-N-Glycosylase (UNG) - Substitute dUTP for dTTP
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-What is the threshold cycle (CT) in real time PCR?
-If the CT is in an earlier cycle, what does that tell you about the original quantity of DNA? |
-CT is when the system begins to detect the increase in the signal associated with an exponential growth of PCR product during the log-linear phase
-early CT means there were more copies of DNA to start with |
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The slope of the log-linear phase in real time PCR is a reflection of what?
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the amplification efficiency.
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Mutation of what gene makes patients with metastatic colon cancer resistant to treatment with EGFR inhibitors (cetuximab, panitumumab)?
What are the 2 codons most commonly mutated? |
KRAS. Mutations of codons 12 or 13. KRAS becomes activated regardless of EGFR activity.
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EGFR is in what family of receptors? What are the 5 major proteins in the EGFR pathway?
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EGFR (tyrosine kinase) -> KRAS -> BRAF -> MEC -> ERK/MAPK
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Methylation occurs on which nucleotide base (A,G, C, or T)?
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Methylation occurs on C, forming 5'-methylcytosine. For a C to be methylated, it must be next to which base (A,C, G or T)?
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C must be next to a G to get methylated. Thus, CpG islands are areas of DNA that become methylated.
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Deamination reaction converts 5'-methylcytosine (methylated cytosine) into which nucleotide base (A, G, C, or T)?
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5'-methylcytosine is deaminated to form thiamine (T). Thus deamination leads to mutation (C into T) - common cause of sporadic mutation in DNA.
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