PLTW - PBS Test Questions with Correct Answers Latest Update 2025-2026
Forensic scientist career - Answers A professional involved in applying scientific principles to solve
crimes.
Search methods - Answers Techniques used in crime scene investigations, including link, line, grid, zone,
spiral, and wheel/ray.
Biomedical scientist career - Answers A professional who applies biology and chemistry principles to
medical research and diagnostics.
Polygraph details - Answers Information regarding the use of polygraphs to measure physiological
responses to determine truthfulness.
Physiological responses seen in liars - Answers Four responses that may indicate deception, typically
measured during a polygraph test.
Locard's exchange principle - Answers The concept that the perpetrator of a crime will bring something
into the crime scene and leave with something from it.
Trace evidence definition - Answers Small amounts of material that can be transferred during a crime,
such as hair or fibers.
How to use a microscope - Answers Using different magnifications: low, medium, high, and oil
immersion to observe specimens.
Types of evidence at a scene - Answers Categories of evidence including hair, fingerprints, digital life,
and blood.
Hair structure layers - Answers The three layers of hair: cortex, medulla, and cuticle.
Stages of hair life cycle - Answers The three stages: Anagen (growth), Catagen (shrinking), and Telogen
(shedding).
Fingerprint origin - Answers The three layers of skin from which fingerprints originate.
Main categories of fingerprints - Answers The three primary classifications of fingerprints.
Minutiae / 12 point match meaning - Answers Specific details in fingerprints used to establish identity
through comparison.
Digital forensics - Answers The process of recovering and investigating material found in digital devices.
Blood cell types and platelets - Answers Different types of blood cells and their specific functions in the
body.
, Presumptive vs confirmatory tests - Answers Presumptive tests indicate the possibility of a substance,
while confirmatory tests definitively identify it.
Presumptive blood tests - Answers Three different tests used to indicate the presence of blood:
Leucocrystal Violet (LCV), Luminol, and Kastle-Meyer.
Leucocrystal Violet (LCV) - Answers A presumptive blood test that reacts with hemoglobin to produce a
violet color, typically used on porous surfaces.
Luminol - Answers A chemical that glows blue in the dark when it comes in contact with blood, but can
react with other substances.
Kastle-Meyer test - Answers The most common presumptive blood test that uses phenolphthalein to
react with iron in hemoglobin.
Blood typing / ABO system - Answers A classification system for blood based on the presence of antigens
and antibodies.
Blood spatter analyst career - Answers A professional who studies blood patterns to understand the
events surrounding a crime.
Blood spatter pattern descriptions - Answers Descriptions of different blood spatter patterns including
straight fall, spatters, transfer, and force/direction.
DNA structure - Answers The double-stranded structure of DNA that can be drawn and analyzed.
Parts of a nucleotide - Answers The three components that make up a nucleotide: a sugar, a phosphate
group, and a nitrogenous base.
Purine vs pyrimidine bases - Answers Two categories of nitrogenous bases in DNA; purines include
adenine and guanine, while pyrimidines include cytosine and thymine.
Histones role - Answers Proteins that help package DNA into structural units called nucleosomes.
Prokaryotes vs Eukaryotes - Answers Prokaryotes are single-celled organisms without a nucleus, while
eukaryotes have a nucleus and organelles.
Gene definition - Answers A segment of DNA that contains the instructions for building a specific
protein.
Chargaff rule problem - Answers A calculation involving the percentage of nucleotide bases in a DNA
molecule.
Histones / chromosome structure - Answers The arrangement of histones and DNA into a compact
structure known as chromosomes.
Forensic scientist career - Answers A professional involved in applying scientific principles to solve
crimes.
Search methods - Answers Techniques used in crime scene investigations, including link, line, grid, zone,
spiral, and wheel/ray.
Biomedical scientist career - Answers A professional who applies biology and chemistry principles to
medical research and diagnostics.
Polygraph details - Answers Information regarding the use of polygraphs to measure physiological
responses to determine truthfulness.
Physiological responses seen in liars - Answers Four responses that may indicate deception, typically
measured during a polygraph test.
Locard's exchange principle - Answers The concept that the perpetrator of a crime will bring something
into the crime scene and leave with something from it.
Trace evidence definition - Answers Small amounts of material that can be transferred during a crime,
such as hair or fibers.
How to use a microscope - Answers Using different magnifications: low, medium, high, and oil
immersion to observe specimens.
Types of evidence at a scene - Answers Categories of evidence including hair, fingerprints, digital life,
and blood.
Hair structure layers - Answers The three layers of hair: cortex, medulla, and cuticle.
Stages of hair life cycle - Answers The three stages: Anagen (growth), Catagen (shrinking), and Telogen
(shedding).
Fingerprint origin - Answers The three layers of skin from which fingerprints originate.
Main categories of fingerprints - Answers The three primary classifications of fingerprints.
Minutiae / 12 point match meaning - Answers Specific details in fingerprints used to establish identity
through comparison.
Digital forensics - Answers The process of recovering and investigating material found in digital devices.
Blood cell types and platelets - Answers Different types of blood cells and their specific functions in the
body.
, Presumptive vs confirmatory tests - Answers Presumptive tests indicate the possibility of a substance,
while confirmatory tests definitively identify it.
Presumptive blood tests - Answers Three different tests used to indicate the presence of blood:
Leucocrystal Violet (LCV), Luminol, and Kastle-Meyer.
Leucocrystal Violet (LCV) - Answers A presumptive blood test that reacts with hemoglobin to produce a
violet color, typically used on porous surfaces.
Luminol - Answers A chemical that glows blue in the dark when it comes in contact with blood, but can
react with other substances.
Kastle-Meyer test - Answers The most common presumptive blood test that uses phenolphthalein to
react with iron in hemoglobin.
Blood typing / ABO system - Answers A classification system for blood based on the presence of antigens
and antibodies.
Blood spatter analyst career - Answers A professional who studies blood patterns to understand the
events surrounding a crime.
Blood spatter pattern descriptions - Answers Descriptions of different blood spatter patterns including
straight fall, spatters, transfer, and force/direction.
DNA structure - Answers The double-stranded structure of DNA that can be drawn and analyzed.
Parts of a nucleotide - Answers The three components that make up a nucleotide: a sugar, a phosphate
group, and a nitrogenous base.
Purine vs pyrimidine bases - Answers Two categories of nitrogenous bases in DNA; purines include
adenine and guanine, while pyrimidines include cytosine and thymine.
Histones role - Answers Proteins that help package DNA into structural units called nucleosomes.
Prokaryotes vs Eukaryotes - Answers Prokaryotes are single-celled organisms without a nucleus, while
eukaryotes have a nucleus and organelles.
Gene definition - Answers A segment of DNA that contains the instructions for building a specific
protein.
Chargaff rule problem - Answers A calculation involving the percentage of nucleotide bases in a DNA
molecule.
Histones / chromosome structure - Answers The arrangement of histones and DNA into a compact
structure known as chromosomes.
