#2

Question 1

Understand that blood is extremely difficult to completely clean.

Answer 1

^^

Question 2

Identify locations where latent blood might be located – even after cleaning.

Answer 2

Look for blood in locations where water is found

Might be:
-under tiles, in cracks of wooden floors, in screw mechanisms of faucets, etc.

Question 3

Identify the specific type of chemical reaction used in blood identification.

Answer 3

Redox reactions

Question 4

Latent blood identification can be very

Answer 4

Sensitive - but only suggests the presence of blood

Question 5

What are the few limitations for the latent blood identification test

Answer 5

1) easy chemical contamination

& 2) always preform a negative control (distilled H2O) & a positive control (dried animal blood) to verify results

Question 6

List the three main causes of chemical contamination.

Answer 6

• breaks down the oxidant (haemoglobin)
• interacts w/test reagant= false positive
  -not known how often false positives occurs
  -some chemicals that affect blood testing
  ~potatoes, red onions
  ~ femic sulfate(iron3sulfate)=Fe2(SO4)3

Question 7

What are the four test to detect blood

Answer 7

Luminal
Kastle-Meyer Test
Titanium dioxide test
Infrared imaging

Question 8

Luminal is

Answer 8

1) One of the most effective presumptive tests
2) Does not affect DNA analysis
3) If blood is present, haemoglobin causes reaction that produces a faint bluish glow
4) extremily sensitive
- can detect blood in soils 1 yr after it is split
- can detect blood on machine washed clothing

Question 9

What are the luminal limitations

Answer 9

1) Luminescence does not last long
2) glow is very faint; need dim light to see it
3) false luminescence can occur
- may look like mist-like blood stains
- don’t use if such stains might be present

Question 10

Kastle-Meyer test is

Answer 10

1) Hydrogen peroxide to produce free oxygen radicals(ions)
2) these free radicals cause color change in phenolphalwin
- turns from clear liquid to a pink liquid
3) quick, cheap, simple, and color change immediately

Question 11

Kastle-Meyer limitations

Answer 11

Less sensitive than luminal test

Does interfere with DNA analysis

Question 12

Titanium dioxide test is

Answer 12

1) 10% w/v solution of titanium dioxide in methanol
2) is a white spray that sticks to blood
- makes seeing blood easy on dark surfaces

Question 13

Titanium dioxide limitations

Answer 13

Flammable and poisonous

Compromises further analysis

Question 14

Infrared imaging is

Answer 14

1) Part of the electromagnetic spectrum
2) from lowest energy to highest energy
- radio, micro, infrared, visible light, ultraviolet, X-ray, gamma
3) radiation associated with heat
4) all objects emit and absorb specific amounts of IR
5) shows potential for identifying latent
blood without using chemicals
6) still in development stage but shows high sensitivity

Question 15

Describe scenarios where blood might be left at a crime scene, but is not relevant to the crime.

Answer 15

Pets fight, play and get hurt

And cooking with raw meet

Question 16

Identify the name of the test used to determine if the blood is human or animal.

Answer 16

Use precipitin tests to determine human or animal

Question 17

How do you use the precipitin test

Answer 17

1) Mix antigens of sample with anti-human antibodies(raises in rabbits)
2) if precipitate forms, antigens and antisera(antibodies) react-means blood is human
3) If animal, other specific antisera is used to determine species of animal

Question 18

DNA analysis of blood is

Answer 18

1) available now
2) likely to supersede precipitin test in future
3) use polyermase chain reaction (PCR) test
- use primers for human mitochondria cytochrome b gene
- If one band results= human blood
- if no band results= animal blood