DNA Flashcards
Structure of DNA
Double helix
2 sugars: deoxyribose, phosphate molecules
Nitrogenous bases
How many N-bases are there? Name and list their pairs
4 nucleotides: A,T,C,G
A <–> T | C <–> G
RNA structure
Single stranded
2 sugars: ribose, phosphate molecules
4 nitrogenous bases
RNA specific pairs
A <–> U | C <–> G
Where does DNA come from?
Both parents (50/50)
Mitochondrial DNA - only from mother (generational tracking)
Where does DNA reside? What is it used for in Forensics
DNA resides in the Nucleus of cells: used to identify victim or perpetrator in a crime
Mitochondrial DNA: used for family investigations to obtain DNA of victim or perpetrator (only used if nucleus doesn’t help)
What codes for DNA?
Genes: Code for proteins
How many different versions of Genes can people have? What are they called?
2 - one from each parent
Alleles: different versions of genes
What are Hydrogen Bonds? What are their significance?
Hydrogen bonds: slight attraction between neg O and pos H or water molecules
Connect the bases of nucleotides
How many bonds do each pair have? can they be damage/broke?
A-T have 2 bonds, C-G have 3 bonds (harder to break)
Can be denatured by heat and change in pH
What is PCR? Significance in forensics?
Polymerase Chain reaction: creates more copies of DNA by separating strands and replicating them
What is STR? Significance?
Short Tandem Repeats (don’t code): used to identify specific individuals (almost completely unique to 1 person)
How many STR do you look for and where do you find them? How are they Read?
13: Established by the FBI
Locus & Loci: places in the DNA STR are found
STR are recorded in peaks on a monitor: height of peaks determine amount of repeats
1 peak - Homozygous
2 Peaks - Heterozygous
Recessive and Dominance
Recessive - homozygous
Dominant - heterozygous or homozygous
Codominance - both dominant traits show
Incomplete dominance - both traits mix
