Forensics DNA Unit Test

What is an organelle?

a small structure in a cell that is surrounded by a membrane and has a specific function

cell nucleus

major organelle in the cell that controls the functions of the cell that also contains DNA

chromosomes

organelles within the nucleus that contain genes. Humans have 46 chromosomes that are paired off (23 pairs); one pair is responsible for the sex of the individual

genes

a sequence of nucleotides that, taken together, tell your body how to make specific proteins, that in turn determine what different cells do

nucleotide

repeating chemical unit that, when all linked together, create DNA (nucleotides have one of four possible bases: A-T, C-G)

what is a double helix?

nucleotides form complimentary base pairs (A-T, C-G)

What is an STR?

Short tandem repeat; repeating patterns base pairs that occur in non-coding regions of DNA. # of repeats that’s getting analyzed in modern DNA profiling

What does it mean to amplify DNA?

when the dna is copied multiple times

What is PCR?

Polymerase chain reaction. It is a method of DNA analysis where a non-coding section of DNA is identified, isolated, unzipped, copied with polymerase enzyme, and run through gel.

what is the amelogenin gene (AMEL)?

a gene that codes for tooth enamel that happens to exist on X and Y chromosomes and can be used to determine the sex of an individual (class evidence)

What is mtDNA?

mitochondrial DNA. Unlike regular DNA, mtDNA is circular, smaller, and can only be passed down from mothers (class evidence)

How do you determine the sex with AMEL?

gel testing that results in 1 or 2 bands: 1 band = only x present = female; 2 bands = xy present = male

What is the relationship between STRs and alleles?

Every individual has two alleles per STR, one inherited from each parent.

How is someone homozygous for an STR?

If the inherited alleles for a given STR in an individual are identical; i.e., contain the same number of repeat units (1 bar in gel analysis)

How is someone heterozygous for an STR?

If the individual has inherited two different alleles for a given STR (2 bars on gel analysis)

What are restriction enzymes (RFLP) and their role

Chemicals that bind to a distinct sequence of base pairs (***recognition site***). The restriction enzyme cuts the DNA at the recognition site. This method takes longer to process and is more expensive

What are Y-STRs?

STRs on the y-chromosome. Y-STRs can only be passed down paternally.

What are the role of base pairs in DNA replication?

The fact that each base only pairs with only one other base allows us to make copies

In STR analysis, what does it mean for a band to go a further and/or shorter distance

Smaller STRs go a further distance, larger STRs go shorter distances