6 Protein forensics Flashcards
A small sample of DNA was taken from each species of grey tree frog. This DNA was amplified, fragmented and used to produce a DNA profile (DNA fingerprint) for each species.
Describe how a DNA profile was produced from this small sample of DNA. 6
- multiple copies of DNA are made
- using PCR
- detail of PCR
- restriction enzymes/endonuclease produce DNA fragments
- Gel electrophoresis
- DNA onto agarose gel (buffer solution added)
- electric charge applied (movement)
- southern blotting or dye to make DNA visible
Suggest how these DNA profiles of two species of frog were compared.3
comparing number, position and width of bands
The DNA produced by PCR was analysed to find out if a black panther was involved.
Explain how gel electrophoresis could be used to find out if this DNA came from a black panther.5
- agarose gel used, sample placed in well, electrical current applied
- use of stain or southern blotting
- use of panthers STRs or DNA
- compare bands in profile
- match=panther DNA was present
The quantity of worm DNA in the beetle gut was very small. Describe how sufficient DNA was produced to carry out the analysis.3
- PCR + detail
- the procedure repeats doubling DNA each time
- temp denatures and anneals
Describe the movement of the DNA fragments in gel electrophoresis?1
SMALL fragments move further then LARGE fragments towards the ANODE
Treatment T3 is
A heated to 90-95
B heated to 75
C cooled to 55-60
D cooled to 4
B heated to 75
Treatment T2 is
A heated to 90-95
B heated to 75
C cooled to 55-60
D cooled to 4
C cooled to 55-60
Treatment T1 is
A heated to 90-95
B heated to 75
C cooled to 55-60
D cooled to 4
A heated to 90-95
what is the name of the enzyme used in the process used to amplify the DNA in a small sample of blood taken from the crime scene.
A endonuclease
B invertase
C polymerase
D transcriptase
C polymerase
Name the process that could be used to separate DNA fragments to create the profiles shown in the diagram above.
A amniocentesis
B electrophoresis
C endocytosis
D chromatography
B electrophoresis
Suggest how DNA profiling could be useful to scientists who examine fossils of animals and plants.2
- comparison between DNA from fossils and other organisms
- to find genetic relationships
- to determine a common ancestor
Explain why evidence from DNA profiles may not be absolutely conclusive.2
- several stages where contamination can occur
- identical twins may show the exact same profile
- only a small section of DNA is analysed
Suggest which of the suspects is most likely to have left the blood sample on the broken window pane. With reference to the theory used in DNA profiling, explain how you came to this conclusion.5
-suspect 3
WHY-
- matches all of the bands
- DNA profiling assumes every individuals DNA is unique, APART from identical TWINS
- intons(non-coding genes) are analysed
- large number of introns = many combinations
