Trace Evidence (PowerPoint download) by liaoqinmei

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									Bellringer
   1. What is “serology”?
   2. What body fluids do you think
      would fall under this study?
Serology
                                  Objectives:
    2.0 Explain ways to collect and preserve
               evidence from a crime scene.
        2.1 Distinguishing between physical
             evidence and witness evidence
        2.5 Describing ways to identify hair,
                   fiber, and blood evidence
              4.0 Describe presumptive and
       confirmatory tests. Examples: blood
             type comparison, DNA testing.
     5.0 Describe the importance of genetic
                   information to forensics.
Bodily Fluids
   •   Blood
   •   Saliva
   •   Tears
   •   Perspiration
   •   Pus
   •   Semen
   •   Human milk
   •   Which 2 bodily fluids do you think are
       most common at crime scenes?
DANGER!!!
   • What would be potential dangers
     of working with bodily fluids?
   • What precautions should be
     taken?
Secretors vs.
nonsecretors
   • From what fluids can blood type
     be determined?
   • 65-80% of the population can be
     blood typed from their body
     fluids.
   • These people are known as
     secretors.
   • What body fluid (other than
     blood) is easiest to blood type?
Components of
Blood
   1. RBC’s –
     1. Red blood cells
     2. Transport oxygen and carbon
        dioxide
   2. WBC’s –
     1. White blood cells
     2. fight infection
   3. Platelets – help in clotting
   4. Plasma – contains salts and
      proteins
Blood Types?
   • Based on proteins:
       – Antigens – on surface of RBC’s
       – Antibodies – in plasma
   • A
   • B
   • AB
   • O
   • Additional subgroups (proteins on
     RBC’s)
   • Which type is most common?
   • Which is least common?
Blood Types
   1. Type A has:
     1. A antigens on RBC surfaces and
     2. B antibodies in plasma
   2. Type B has:
     1. ?
     2. ?
   3. Type AB has:
     1. A and B antigens
     2. NO antibodies
   4. Type O has: ???
Rh Factor Blood
Grouping
   • Rh factor is another antigen
     found ____________.
   • Rh+ means you have the antigen.
   • Rh – means ???
   • Rh – DOES NOT mean you have
     Rh antibodies in the ________,
     but you may develop antibodies if
     you receive Rh+ blood.
   • Rh + people can receive Rh-
     blood with no problems.
Blood Groupings
   •   On a separate sheet of paper:
       1. List all the possible blood
          groups.
       2. Tell which blood types can
          receive blood from each blood
          type.
Favorite College
Teams
   • Alabama (U)
   • Auburn (A)
   • If you like U, you DON’T like
     ____.
   • If you like A, you DON’T like
     ____.
Favorite College
Teams,
continued…..
   • If you like A, you are ANTI-
     ____.
   • If you like U, you are ANTI-
     ____.
   • Some fans will actually
     FIGHT fans of the other
     team. (antibodies)
Favorite College
Teams,
continued…..
   • A new twist:
   • You can be for U or A, and
     indifferent to Florida (F) -
     although I can’t understand
     that kind of mentally.
   • HOWEVER, how do you feel
     about F if they are playing your
     team in the SEC championship
     game?
Favorite College
Teams “Blood
Types” Assignment
   • Identify the following and give
     1-letter symbols:
     1.   Favorite team
     2.   “Enemy” team
     3.   A “neutral” team
     4.   A 2nd-favorite team
Favorite College
Teams “Blood
Types” Assignment
   • Write the symbols for each
     combination of “blood type”
     you can make from these
     teams, and what each symbol
     means.

								
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