Quiz 4 Flashcards
Influencing Factors
Charge of molecule (DNA carries a negative charge; is placed at negative end and will be attracted/travel to the positive end)
Size (smaller molecules/fragments will travel faster and further)
Density of gel (more dense the slower the particles will move through it)
agarose gel goes into
negative end (black) DNA will flow to the positive end “run to red”
Rate of migration is _____ to size of DNA fragments
inversely proportional
Size measured in
bp
Cortex
contains natural pigmnt (melanin) and moisture
Medulla
Core of hair
may even be absent
Cuticle
outer layer f hair shaft (overlapping keratin cell)
works as protective sale
transparent
Presumptive blood evidence
Blood identified by presence of hemoglobin
-carries O2 to tissues and CO2 back to lungs
The Kastle-Meyer Test
-Ethyl alcohol (exposes residual hemoglobin to increase intensity of reaction
Kastle-Meyer phenolthalein
-Colorless-> exposed to 02 -> pink
Hydrogen peroxide (H2O2)
-reacts with hemoglobin
Hair strands are composed of
keratin (a protein), melanin (a pigment) and trace elements deposited during growth or absorbed from environment,
The root of a hair contains three areas
cuticle
cortex
medulla
basis for evidentiary comparison
forensic evidence
is any object or material that may connect an offender to a crime scene
Physical evidence
weapons, ballistics results, tire tracks, possession of stolen materials, or witness testimony
electronic evidence
computers/ digital evidence
biological evidence
DNA, Blood, fingerprint or hair analysis
DNA
organic molecule with nucleotides as building blocks
genetic blueprint
small sample is enough to prove innocence
DNA Replication
Double stranded DNA gets unwound
new nucleotides added to single strands
two copies of double stranded DNA
semi-conservative replication
PCR
used to amplify small amounts of DNA into testable amounts
Reaction enzymes
bacterial enzymes that recognize and cut DNA at specific sequences
Molecular scissors
RFLP
Restriction Fragment Length Polymorphisms
restriction sites are deleted or added through mutations
same restriction enzyme is used to cut the DNA and band patterns
at least 5 RFLP markers are tested in crime cases
the more markers used the less likely it is anyone else
can be used in paternity cases
frags are separated using gel electophoresis
Restriction endonucleases
specialized enzymes that digest specific portions of DNA
Gel electrophoresis method
separate mixture of molecules through a gel under the influence of an electrical field
Three enzymes that are vital to cell function are
structural protiens that support cells and tissues
enzymes that carry out metabolism functions
regulatory proteins that determine how and when genetic information is expressed to manufacture proteins
