DNA Flashcards
DNA can be described as
an inherited molecule, randomized from your mom and dads DNA, that can be used to identify someone
the scientist who developed the first method of DNA fingerprinting
Alec Jefferys
the subunit of DNA; composed of a phosphate group, deoxyribose sugar, and nitrogen base
nucleotide
the nucleotide is composed of
a phosphate group, deoxyribose sugar, and a nitrogen base
nuclear is the type of DNA
inherited from both parents and considered uniquely identifying (unless have a identical twin)
chromosome
structure where hereditary information is transmitted from one generation to the next
mitochondrial DNA (mtDNA)
inherited from your mother and used in cases where human remains have been highly degraded
enzyme that cuts DNA into smaller pieces
restriction
which bases pair together
cytosine and guinine
adenine and thymine
STR
non-coding segment of DNA that is 2-6 base pairs long and can repeat up to 200 times
analysis of tandem repeats
gel electrophoresis
process used to separate DNA by fragments by size, individual to each person, separates by size
what was the first DNA analysis technique developed in the 1980’s
RFLP and it requires a lot of cells, uses junk segments of DNA (tandem repeats)
VNTR
a non-coding segment of DNA that repeats a different amount of tandem repeats from person to person
PCR
a process in which one or more specific small regions of the DNA are copied so that a sufficient amount of DNA is generated for analysis
CODIS
a collection of databases of DNA profiles obtained from unsolved crimes and from known individuals convicted of particular crimes
CODIS database which evaluates 13 specific DNA locations
in a gel electrophoresis contraption where do you place the DNA
which side are the wells on
wells
negative side going towards positive
short=
long=
faster
slower
characteristics of RFLP (type of VNTR)
large repeated sequences, large amount of sample, takes a long time for results, and unique
characteristics of PCR-STR (type of VNTR)
short repeated segments, less DNA small amount sample (PCR), shorter time for results, 13-20 STR’s to create profile
What makes DNA evidence unique?
Because it is inherited from both parents in a completely random fashion.
How are DNA profiles stored?
1)Need a minimum of 9 cells to create a DNA profile, 2)all possible sources of DNA need to be photographed or documented before collected, 3)packaged in separate paper bags or envelopes (gloves changed in between handling different evidence), 4) swabs used to collect samples must air dry before placed in swab box, 5)all biological fluids should be handled with least amount of personal contact, 6)all clothing from victims and suspects is collected, 7)stored in cool, dark place, standard samples need to be taken
DNA Fingerprinting is the analysis of
analysis of the lengths of the fragments that reveal that when looking at multiple VNTRs within and between individuals, no two people have the same assortment of lengths.
Polymerase Chain Reaction (PCR)
a process used in DNA identification testing in which one or more specific small regions of the DNA are copied using a DNA polymerase enzyme so that a sufficient amount of DNA is generated for analysis.
Restriction Enzyme
a protein harnessed from bacteria that recognizes specific, short nucleotide sequences and cuts DNA at those sites
Variable Number of Tandem Repeats (VNTRs)
repeating units of a DNA sequence
sides of ladder
sugars and phosphates held together by covalent bonds
rungs are made of
nitrogen base pairs containing hydrogen bonds
term double helix was created by
watson and crick
char gaff’s rule
the DNA of any organism must contain equal amounts of A and T and equal amounts of C and G
helicase process
breaks hydrogen bonds between two nucleotide strands
uncoiling and unzipping the DNA
creating each new strand that is now a template
DNA ligase
“glues” the new nucleotide strands together
semiconservative replication
DNA molecule is made of one old side and one new side, 2 new DNA are identical
how can DNA help investigators
identify unknown remains
link serial crimes
identify number of suspects/victims involved
identify possible individuals whose DNA had been stored in DNA database
exonerate people who have been wrongfully convicted
minimum of __ cells to create a DNA profile
9
uses of DNA fingerprints
paternity testing
identifying remains
match suspect DNA with crime scene DNA
weakest bond in DNA
hydrogen bonds
phosphate:
sugar:
bonds:
- small circle
- pentagon
- hexagon
