ETC ETC Biological & DNA Evidence

Question 1

Which presumptive test is used to detect the presence of seminal fluid at a crime scene?

Accepted Answer

Acid phosphatase test

Answer

The acid phosphatase test detects the enzyme acid phosphatase found in high concentrations in seminal fluid; a positive result turns the reagent purple.

Question 2

What is the proper technique for collecting a dried bloodstain from a non-porous surface?

Accepted Answer

Moisten a sterile swab with distilled water, collect the stain, air dry the swab completely, and package in paper

Answer

Dried bloodstains on non-porous surfaces should be collected with a moistened sterile swab, air-dried to prevent bacterial degradation, and packaged in breathable paper.

Question 3

What is touch DNA and from what type of evidence can it be collected?

Accepted Answer

DNA from skin cells deposited through touch — collectible from surfaces like doorknobs, weapons, and steering wheels

Answer

Touch DNA refers to trace skin cells (epithelial cells) left when a person touches a surface; it can be collected from any object a suspect may have handled.

Question 4

Why should biological evidence never be packaged in sealed plastic bags for long-term storage?

Accepted Answer

Moisture trapped inside promotes bacterial growth and mold that degrades DNA

Answer

Sealed plastic traps moisture, creating an environment where bacteria and mold thrive, rapidly degrading biological evidence and the DNA within it.

Question 5

Which body fluid is identified by the presence of p30 (PSA) protein confirmed by immunological testing?

Accepted Answer

Seminal fluid

Answer

p30, also known as prostate-specific antigen (PSA), is a protein found in semen and is used as a confirmatory marker for seminal fluid in sexual assault evidence.

(ETC) Evidence Technician Certification Practice Test

(ETC) Evidence Technician Certification Practice Test

ETC ETC Biological & DNA Evidence