Exam 1 Flashcards
What happens when a DNA molecule is denatured?
Any double-stranded molecule becomes single-stranded.
What DNA extraction procedure presented in the lecture requires the fewest pieces of laboratory equipment?
FTA paper
The different variations in locus DNA sequence that may exist in a population of organisms are called? [What?]
Alleles
A semen stain is confirmed if the analyst can see
Sperm cells
What is the purpose of a differential extraction?
To separate the sperm and vaginal epithelium DNA when the sample is a mixture of those cell types
The following letters below represent the base sequence of a single-stranded DNA molecule.
TAATTCGAGCTGAATTAGGA 3’
Not included: ATTAAGCTCGACTTAATCCT 5’
Correct sequence: TCCTAATTCAGCTCGAATTAT
What are the three typical temperature steps in a thermal cycler program?
Denaturation
Annealing
Extension
During a DNA extraction procedure, what are two potential ways to protect the sample DNA from nucleases in the tissue?
Heat
Chelation
Proteanase
The concentration of a DNA extract may be determined by spectrophotometry and absorbance at 260 nm and at 290 nm. What is the purpose of using two wavelengths?
DNA absorbs at 260 nm and proteins absorb at 290nm. The goal is maximize DNA concentration and minimize protein concentration.
What is the approximate length, in bases, of the DNA in a single human cell?
~6,000,000,000 [accepted ~3,000,000,000 for a haploid set]
What is the difference in length, in bases, between alleles 6.2 and 7 of a tetranucleotide repeat STR locus?
Two
What are the two components of the detector in a capillary DNA analyzer?
An argon laser and a digital camera
In the typical forensic lab DNA analyzer, the sample (after having been loaded on the instrument) is moved to the capillary for injection by the
Autosampler
