Topic 6 - Infection, Immunity And Forensics Flashcards
What are fingerprints?
Fingerprints are unique patterns caused by folds in the epidermis of the fingertips
What are the four patterns seen in fingerprints?
- arches
- whorls
- loops
- tented arches
Describe how fingerprints are collected.
A magnet and iron filings are used. The iron filings stick to the grease on the fingerprint and the magnet removes any excess iron. As a brush never actually touches the print, it gives a sharper result
How many points of a fingerprint must match to identify the print?
16 points
What are the names of the different areas of Dna and what is the difference?
-introns and exons
Exons code for proteins whereas introns are non-coding.
What are short tandem repeats?
Short DNA sequences that are repeated many times within introns, containing 2 to 50 base pairs and repeated 5 to several hundred times
How are STRs used to identify people?
The same short tandem repeats appear at the same loci on homologous pairs and in everyone’s Dna. However, the number of repeats at these loci vary between both these. The chance of two people having the same number of repeats is exceedingly small.
What is the first step in processing a Dna sample?
The sample is physically broken down in a buffer solution containing salt and detergent to disrupt the cell membranes. It is filtered or put in a centrifuge and protease enzymes are used to remove proteins. Cold ethanol is used to precipitate out the dna.
How are fragments of DNS removed from the sample?
Restriction endonucleases are used to remove sections of STRs. They are found in bacteria, where their purpose is to cut up invading viral dna.
What process amplifies a sample of DNA?
Polymerase chain reaction
What are the reagents in PCR?
DNA sample
DNA primer (with fluorescent tags)
DNA polymerase
Nucleotides
What forensic techniques are used to identify bodies?
- fingerprinting
- dental records
- Dna profiling
