deck_15228047 (1)

Question 1

What are the possible reasons for the difference?

Answer 1

1. surface texture
2. impact velocity

Question 2

What are the steps needed for DNA extraction?

Answer 2

Cell lysis: breaking open cells to release the DNA DNA Precipitation: Separating the DNA from other cellular components DNA Purification: removing impurities to obtain pure DNA.

Question 3

Give a description of the shape of blood droplets on porous and nonporous surfaces.

Answer 3

On porous surfaces, blood droplets may appear more spread out but on NON porous surfaces they maintain a more circular shape with less absorption to the material its on—–> dropping blood on paper vs lab table.

Question 4

the three most distinctive patterns we discussed are gunshot, stabbing, and blunt object impact.

Answer 4

gunshot = <1mmstabbing = 1-4mmblunt object = 4-6mm

Question 5

define the area of convergence and area of origin an explain what each reveal to an investigator

Answer 5

AOC = the area 2D plane where lines traced through the long axis of several indiv bloodstains meet apprx from which bloodstains were projected

AOO= 3D space where a bloodstain originated from. location of AOC and AOI for each bloodstain is apprx this arterial sprayA characteristic bloodstain pattern containing spurts that resulted from blood exiting under pressure from an arterial injury

Question 6

What factors are considered evidence?

Answer 6

1. location2. distribution3. appearance4. direction5. dropping distance6. angle of impact

Question 7

compare a polymerase chain reaction to a short tandem repeat

Answer 7

PCR = copy DNA strands, amplify minute quantities, shorter strandsSTR = latest method of DNA typing, region of DNA molecule containing short segments of 3 to 7 repeating base pairs

Question 8

The width of thebloodstain was measured at 2.3mm, with the length of the blood stain being measured at 2.9mm. What is theangle of impact?

Answer 8

Width/Length and use tan-1, then multiply by180tan-1(2.3/2.9) =xx(180)= answer in degrees