Unit 1.1 Test

Biomedical Science

Link Method

Link Method

Used to find associations between evidence. Investigators evaluate the scene and then proceed through the area in a systematic and logical fashion

Line (Strip) Method

Used on large outdoor crime scenes. Members of the search team are arranged at intervals and search along straight lines

Grid Method

Used on large outdoor crime scenes. Searchers follow the first line pattern, once that is complete, they follow on the other line pattern

Zone Method

Used on crime scenes that are comprised of readily definable zones, such as houses or buildings. Teams are assigned in small zones for searching, the other searching methods are employed in each zone

Spiral Method (Inward or Outward)

Used on crime scenes with no physical barriers, such as open water. Can either being at critical point of crime scene (outward spiral) or the outer edge of the crime scene (inward spiral)

Wheel or Ray Method

Used on small circular crime scenes. Investigators start at a critical point and travel outward along many straight lines from this point

What are the steps to do at a crime scene?

1) Secure the scene

2) Witnesses (Identify, Separate, Interview)

3) Protect clothing/tools

4) Document (written description, photograph, sketching, observing)

5) Collecting samples/evidence

6) Analyze evidence

When what happens when you lie? (at least 3)

1) Heart beats faster

2) Warm body feeling

3) Emotions

4) Stutter

5) Relive the moment

6) Deliberate thinking

7) Fidgeting/shaking

8) Eye contact

9) Awkward laughter

10) Goosebumps

11) Sweating

What is measured on a Polygraph test?

1) Heart rate

2) Respiration rate

3) Blood pressure

4) Skin conductivity (sweat contains salt, salt conducts electricity)

AI: Body posture and Eye movement

How do vitals change during a lie?

1) Blood pressure spikes

2) Respiration rate drops/Heart rate spikes

3) Respiration rate increases/Heart rate drops

4) Sweating - most effective

Plain Arch

Arches slope upward then down. The simplest fingerprint.

Tented Arch

Similar to plain arch except the ridges in the center arch coverage thrust upward making a pitched appearance

Loop Pattern

Forms when ridges curve back on themselves

2 types: radical loop (pointing towards the thumb) ulnar loop (point towards the pinky)

Whorl Pattern

Whorls form a circular or spiral

Minutiae

tiny fingerprint ridge details

Occam’s Razor

If there are 2 possible explanations for an event, the one with fewest assumptions is usually correct

Cortex (Analyzing hair samples)

Most dense layer that contains majority of pigment when comparing thickness, color, granules

Cuticle (Analyzing hair samples)

Outermost layer characterized by scaled surface

What are the 4 main blood types?

Type A

Type B

Type AB

Type O

Why are there different blood types?

The difference is due to the presence or absence of particular protein molecules located on the surface of red blood cells

Antigens

surface proteins on red blood cells, a specific type of protein that causes an immune response

What type of antigen does type A blood have?

Type A antigens

What type of antigen does type B blood have?

Type B antigens

What type of antigen does type AB blood have?

Type A and Type B antigens

What type of antigen does type O blood have?

Neither A nor B antigens

Antibodies

A type of protein that circulates in your blood and interact with specific antigens

Aggulation

When antibodies bind to blood cells causign a clumping reaction

Human blood is composed of what 3 main blood cells?

1) Erythrocytes

2) Leukocytes

3) Thrombocytes (platelets)

What does cytes mean?

cell

Presumptive Tests

Kastic-Meyer (hemostick)

Liminol

Confirmatory Tests

ABO Testing

What are Erythrocytes also known as?

Red blood cells

What are Erythrocytes

a blood cell that contains a protein called hemoglobin

What do Erythrocytes do?

They carry oxygen from the lungs to all parts of the body.

What are Leukocytes also known as?

White blood cells

What are Leukocytes apart of?

They are a part of the immune system

What do Leukocytes do?

They protect your body from infection

What are Thrombocytes also known as?

Platelets

What are Thrombocytes?

a blood cell that controls blood clotting and healing

What do Thrombocytes do?

They control blood clotting, help wounds heal, and stops bleeding

What is the difference between an Antigen and an Antibody?

Antigens are protein that causes an immune response, and antibodies are a protein that interacts and binds to specific antigen

How many copies of genes do you have?

2 copies of every gene

one from mother, one from father

What blood type is dominant?

A and B

What blood type is recessive?

Type O

Homozygous

the same (IA IA)

Heterozygous

different (IB Ii)

Blood Splatter

when there is an injury, the pattern the blood leaves on surfaces tells a story

Transfers (Blood stain pattern)

occurs when a blood source comes into contact with a surface (smears, smudges, bloody fingerprints)

Splatter (Blood stain pattern)

produced when a source of liquid blood travels through the air before landing on a surface (like splatters)

Passive (Blood stain pattern)

When a droplet of blood is dropped directly from above and strikes a horizontal surface at 90°, it produces a circular stain.

What does it mean when spatters with an elliptical or elongated shape struck the surface at an angle.

This often means that an external force was applied that provided horizontal velocity, speed in a given direction, to the droplets

The more elongated the droplet

the faster they were moving

What does the long tail of each droplet indicate?

The long tail of each droplet indicates the direction it was moving when it struck the surface

What does DNA stand for?

Deoxyribonucleic Acid

What are the 4 nucleotides DNA is made of?

Adenine, Thymine, Guanine, Cystine

How many complementary strands are in a double helix?

2

If one strands sequence is AGGCTAC then the other strands sequence is

TCCGATC

What is a nucleotide made of?

Phosphate, sugar, and base

Hydrogen bonds

weak attractive force that holds nucleotide strands together

Sections of DNA that code for proteins

Genes

How many chromosomes do humans have?

46

How many chromosomes do humans get from their mother?

23

How many chromosomes do humans get from their father?

23

How many chromosomes in the human body are autosomes?

44

How many chromosomes in the human body are sex chromosomes?

2

What are the 3 parts of DNA fingerprinting?

1) Amplify the DNA

2) Cut the DNA

3) Separate the fragments

What does RFLPs stand for?

Restriction Fragment Length Polymorphism

PCR Amplification

makes millions of copies of DNA (polymerase chain reaction)

Restriction Enzymes Digestion

enzymes taken (originally) from bacteria cut DNA at VERY specific sequences

Gel Electrophoresis

When DNA samples are put into wells (holes) in a gel fin electrical current is applied to see where DNA bonds appear

What type of charge does DNA have?

DNA has a negative charge

How are DNA fragments separated?

separated based on size