LECTURE 1
What happens to the temperature of a body after death?
EXTRA 50 for those who can name what this process is called.
It cools down. Algor Mortis
Name a type of passive blood stain.
Drops, flows, transfers, large volumes.
Adenine - Thymine
Cytosine - Guanine
Which DNA fragments will move faster during electrophoresis?
During electrophoresis, smaller DNA fragments will move faster than larger DNA fragments because they can navigate through the pores of the gel matrix more easily.
Mitochondrial DNA (mtDNA) is important in forensics because it is present in high copy numbers within a cell, allowing for analysis even when DNA is highly degraded, like in old or damaged samples such as hair shafts or bones, which is often the case in criminal investigations; additionally, mtDNA is maternally inherited, meaning it can be used to trace maternal lineage and identify individuals when nuclear DNA is insufficient for a positive match.
What is autolysis?
(Self-Digestion)
Intrinsic cell breakdown via lysosomal enzymes.
Tissues, like the pancreas, digest themselves due to high enzyme content.
What does a positive Kastle-Meyer Test look like?
After adding hydrogen peroxide, free oxygen radicals produced by haemoglobin breakdown react with phenolphthalein, turning it pink.
Name 2 types of RNA
Messenger RNA
Ribosomal RNA
Transfer RNA
What charge does DNA have?
A negative charge
Which slab gel apparatus has a vertical configuration?
Polyacrylamide Gel Electrophoresis
Explain the differences between ante mortem, peri mortem, and post mortem periods
Ante mortem: Before death
Peri mortem: Around the time of death
Post mortem: After death
Why is the vitreous humor forensically significant?
The vitreous humor is typically free of microorganisms, and it is encased by tough membranes that slow its decay compared to other tissue.
What are SNPs?
Single nucleotide polymorphisms (SNPs) are the most common genetic variations, arising from single base differences throughout the genome
What are dyes such as ethidium bromide and SYBR-Green used for?
yes like ethidium bromide and SYBR Green are primarily used to visualize nucleic acids (DNA and RNA) in gel electrophoresis experiments, allowing researchers to see and analyze the separated DNA or RNA fragments under UV light due to their fluorescent properties when bound to the nucleic acid strands; essentially acting as a stain to make the DNA bands visible in a gel image.
With oxygen deprivation, which body cells are the quickest to lead to cell death?
Brain cells
What are 4 factors that enhance the rate of body cooling.
Small body size
Low fat content
Body stretched out
Body dismembered
Serious blood loss
Lack of clothes
Wet clothes
Strong air currents
Low ambient temperature
Rain, hail
Cold, damp substrate that conducts heat readily (e.g. damp clay soil)
Body in cold water
Dry atmosphere
Type O blood has which type of antigens?
No antigens!
STRs, which stands for "Short Tandem Repeats," are short sequences of DNA that repeat multiple times in a row at specific locations on a chromosome, and they are important because their variable repeat numbers between individuals allow for highly accurate DNA profiling used in forensic science, paternity testing, and identifying missing persons, essentially acting as a genetic fingerprint due to their unique patterns across individuals.
What are modular microfluidic devices used for in forensic labs?
Automated sample preparation and analysis. It is rapid, accurate, and useful for on-site analysis of forensically relevant evidence on a crime scene
How can you mathematically test the angle of impact for a bloodstain.
sin(θ) = (width of stain)/(length of stain)
θ = sin^-1 * (width of stain)/(length of stain)
What can strontium isotope ratios be used for?
Strontium isotope ratios vary geographically and can act as a "signature" for the environment in which a person or animal lived. Strontium enters the body through diet and is deposited in bones and teeth
Do red blood cells contain any useful DNA for forensic use? Why or why not?
No. RBCs do not have a nucleus.
What are the steps to a polymerase chain reaction?
Reduce the temperature to 50-60º to allow the primers to 'aneal' the DNA
Raise the temperature to 70-72º to initiate the polymerization stage which Taq DNA polymerase enzyme usese DNA template to reproduce a complimentary copy
The procedure is repeated and amplified thousands of times
PCR products are separated by length.
How long does it take to generate a DNA profile from a single-source sample using fully automated rapid DNA instruments?
A. 90 minutes
B. 30 minutes
C. 24 hours
D. 4 hours
90 minutes
What did I minor in in college?
Chemistry