1.1 - Investigating the Scene 

1.1.1 - crime scene search methods

Methods of processing a crime scene:

Link - no pattern, logical links to crime activity and evidence (any type of crime)

Line - investigates in lines/strips (large outdoor)

Grid - first group searches in lines one way and the other group searches in lines in the opposite direction (large outdoor0

Zone - team members are assigned a specific section (small indoor)

spiral - pick a critical point and spiral outwards/inwards  (crimes with no barriers)

wheel/ray - pick a critical point and travel outwards (small circular)


1.1.2 - experimental design

  1. Identify the question

  2. Make a prediction (hypothesis with id/dependent variables)

  3. Design experiment (experimental controls)

  4. Conduct experiment (collect data)

  5. Analyze data (make graphs/charts

  6. Communicate findings (ideas for research)

Independent variable - manipulated (intensity of exercise)

dependent variable - measurable (heart rate)

Control variable - kept the same (length of exercise)













1.1.3 - Hair and Fingerprints

Hair Structure And Anatomy Including ...

Cuticle - outermost layer 

Cortex - pigment, density, size 

Medulla - middle, adds volume and texture

Fingerprint Patterns | Download ...

Arch - slope upward

Tented arch - dramatic slope

Loop  ridges curve back on themselves

Whorl - circular/spiral


Conversion factor: 

desired unit/given unit 


35ml to uL


uL to mL: 1ml / 1000uL, divide uL by 1000


mL to uL: 1000uL / 1mL, multiply mL by 1000


35/1000 = 0.035 uL





1.2.4 - components of blood and typing 


Plasma - liquid portion, carries nutrients and proteins to the body

Erythrocyte - red blood cells, carry O2 to the lungs and body 

Leukocyte - white blood cells, fight infection

Thrombocyte - platelets, help stop bleeding by clotting 

Hemoglobin - protein in red blood cells that carries oxygen 

Hematocrit - % of erythrocytes in blood (low hematocrit = anemia, low iron)

Agglutination - clumping of erythrocytes 

Presumptive - detect hemoglobin to identify if the substance is blood 

Confirmatory - confirms the antibodies that are present and recognizes the proteins that bind to the sample (determines the blood type)


Types of blood spatter:

Transfer - smear, trail, smudge, finger/handprint

Spatter - blood traveling through the air before landing

Falling droplet - blood is dropped directly above (90 degrees to create a circular stain)

Radical spatter - due to large impact and high speed



1.1.5 - DNA Structure

DNA - negatively charged, double helix, found in all living things, housed in nucleus

Amino acid - building block for DNA 

Ribosome - builds proteins

Protein - large molecule made up of amino acids 

Gene - set of instructions to build proteins

Cell - smallest unit of life 

Chromosome - tightly coiled packages of DNA 

Histone - DNA strands that wrap around proteins

Gamete - sperm/egg cell

DNA extraction - breaking open cells to find DNA inside the nucleus

Restriction enzymes - molecular scissors that cut DNA in recognition sites (specific locations) to become restriction digested (DNA that has been cut)

Blunt ends - wen restriction enzymes cut down the the middle of the recognition sites

Sticky ends - when restriction enzymes cut jagged lines

DNA fragments - digestion that results in small pieces of DNA 

Gel electrophoresis - process the separates/analyzes the digested DNA fragments from blood and organizes them by size


 

Sources of DNA extraction:

  • Leukocytes

  • Bones

  • Hair 

  • Preserved body parts

  • clothing/fiber

  • saliva/body fluids

    • These all have sources of DNA and are found in the nucleus 


Non-sources of DNA extraction:

  • Erythrocytes

    • No nucleus and no DNA