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Transcript of FORENSICS: BLOOD
- Blood typing: provides class evidence
- Use white blood cells to obtain DNA evidence
- Recreate a crime scene with blood spatter evidence
or... recreate other things
red blood cells
white blood cells
RED BLOOD CELLS:
Also known as erythrocytes
Main function is to carry oxygen and carbon dioxide
This is accomplished through
hemoglobin, an iron-
**Red blood cells don't have nuclei.**
So, red blood cells alone cannot be used to
obtain DNA evidence
Hemoglobin makes blood red when oxygen
is bound to it.
WHITE BLOOD CELLS
Also know as leukocytes
White blood cells guard against infection, fight parasites, and attack bacteria.
What does a high white blood cell count tell you?
White blood cells do have nuclei, so you can obtain DNA evidence from them.
Cell fragments that come together to form blood clots
The fluid component of blood
Dissolved in the water are chemicals: salts, proteins, hormones, and waste, to name a few
Less expensive than DNA profiling
Can be used to link or exclude a suspect to the crime scene
The surfaces of all blood cells contain certain proteins
Proteins are either A proteins or B proteins
People have either an A, B, AB, or O blood type
THE RH FACTOR:
Another type of red blood cell surface protein: Rh factor
85% of the population has this protein on their red blood cells
This is where the "+" or "-" comes from in labeling a person's blood type.
U,S. BLOOD TYPE PERCENTAGES:
Type O - 43%
Type A - 42 %
Type B - 12 %
Type AB - 3%
WHAT'S UP WITH THOSE ANTIBODIES?