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Forensic Science. Blood What is made of? SUBSTANCE HOW DO WE KNOW IT’S BLOOD? Human?? Animal?? What does it do when it “travels”? BLOOD SPATTER.

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Presentation on theme: "Forensic Science. Blood What is made of? SUBSTANCE HOW DO WE KNOW IT’S BLOOD? Human?? Animal?? What does it do when it “travels”? BLOOD SPATTER."— Presentation transcript:

1 Forensic Science

2 Blood What is made of? SUBSTANCE HOW DO WE KNOW IT’S BLOOD? Human?? Animal?? What does it do when it “travels”? BLOOD SPATTER

3 What makes up our blood? RED BLOOD CELLS (Erythrocytes) – –MOST ABUNDANT…contain HEMOGLOBIN –Do NOT have a nucleus – so they don’t have _______?? WHITE BLOOD CELLS (Leukocytes) – –IMMUNE CELLS PLASMA – –YELLOWISH LIQUID - nutrients and vitamins, hormones, clotting factors, and antibodies. PLATELETS (Thrombocytes) – –coagulate (clot) your blood, when you have a wound

4 What are blood types? UNIVERSAL DONORS: O type Rh – UNIVERSAL RECIPIENTS: AB type Rh +

5 How common is your blood type? 46.1% 38.8% 11.1% 3.9%

6 How do we know it’s blood? And if it’s blood, is it HUMAN? Is it blood? Kastle-Meyer test Uses Phenolthalein Detects Hemoglobin Turns pink if +

7 KASTLE-MEYER video clip

8 How do we know it’s blood? Is it blood (big area)? Luminol Drawbacks !! Some metals, paints, cleaning products, and plant materials also react. Can destroy DNA in blood.

9 Luminol can destroy evidence (DNA) http://www.youtube.com/watch?v=iNl-I4DUSyI

10 Crime Scene Analysis: Luminol in action

11 And if it’s blood, is it HUMAN? Is it HUMAN blood? Precipitin test 1. Inject rabbits w/ human blood 2. They will make ANTIBODIES to it 3. Extract antibodies from rabbit 4. Combine antibodies w/ crime sample 5. A precipitate line appears in tube if +

12 And if it’s blood, is it HUMAN? PRECIPITIN TEST Draw a test tube

13 And if it’s blood, is it HUMAN? PRECIPITIN TEST Draw a test tube. Like this one…

14 Is it HUMAN?? Microscope Views (visual examination) Bird Blood Cat Blood Dog Blood Fish Blood Frog Blood Snake Blood Human Blood Horse Blood


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