Mock Test Set-24 (Forensic Science)

1. In STR-based forensic DNA profiling, what is the most likely source of allele drop-out in low template DNA samples?

A) Contamination during PCR setup

B) High number of STR loci

C) Stochastic effects during amplification

D) Use of fluorescent dyes

Answer: C) Stochastic effects during amplification

Explanation: Low-template DNA can result in allele drop-out due to stochastic variation during PCR. This leads to failure of one allele (especially in heterozygotes) to amplify, complicating interpretation.

 

2. Which statistical method is most appropriate for evaluating the match probability in mixed DNA profiles involving multiple contributors?

A) Hardy-Weinberg Equilibrium

B) Likelihood Ratio

C) Chi-Square Test

D) Standard Deviation

Answer: B) Likelihood Ratio

Explanation: The likelihood ratio approach quantitatively evaluates competing hypotheses (e.g., inclusion vs. exclusion) in complex DNA mixtures, incorporating population allele frequencies.

 

3. The identification of latent fingermarks on adhesive surfaces like duct tape is optimally performed using:

A) Ninhydrin

B) Powder dusting

C) Cyanoacrylate fuming followed by Rhodamine 6G

D) Silver nitrate

 

Answer: C) Cyanoacrylate fuming followed by Rhodamine 6G

Explanation: On nonporous and adhesive surfaces, cyanoacrylate fuming polymerizes on latent prints. Subsequent staining with Rhodamine 6G enhances visibility under fluorescence.

 

4. Which of the following is NOT a characteristic feature of diatom analysis in forensic drowning cases?

A) Resistance to putrefaction

B) Presence in cerebrospinal fluid confirms drowning

C) Entry through gastrointestinal tract postmortem

D) Siliceous cell wall structure

Answer: C) Entry through gastrointestinal tract postmortem

Explanation: Diatoms enter circulation via alveolar-capillary membranes during drowning, not through ingestion. Their presence in bone marrow/CSF is confirmatory of ante-mortem inhalation.

 

5. Which of the following is most suitable for detecting hydrocarbon accelerants in fire debris?

A) FTIR Spectroscopy

B) GC-FID with passive headspace extraction

C) TGA

D) UV-Visible Spectrophotometry

Answer: B) GC-FID with passive headspace extraction

Explanation: Gas Chromatography-Flame Ionization Detection after passive headspace concentration is ideal for analyzing volatile hydrocarbons from charred debris in arson investigations.

6. The most reliable skeletal indicator of sex in subadult human remains is:

A) Skull shape

B) Mandibular angle

C) Long bone length

D) Greater sciatic notch width

Answer: D) Greater sciatic notch width

Explanation: In subadults, sexual dimorphism is subtle. However, the greater sciatic notch of the pelvis shows early dimorphic traits, making it the most reliable among limited options.

 

7. Which of the following chemical reactions is the basis for the Teichmann test for blood confirmation?

A) Formation of hemin chloride crystals

B) Reduction of hydrogen peroxide

C) Oxidation of phenolphthalin

D) Acid hydrolysis of hemoglobin

Answer: A) Formation of hemin chloride crystals

Explanation: The Teichmann test detects blood via formation of hemin crystals (ferriprotoporphyrin chloride) when hemoglobin reacts with glacial acetic acid and salts.

 

8. In forensic handwriting analysis, the term “line quality” refers to:

A) Thickness and darkness of the pen line

B) Speed, rhythm, and pressure control of strokes

C) Spelling and punctuation

D) Type of ink used

Answer: B) Speed, rhythm, and pressure control of strokes

Explanation: Line quality is a primary handwriting feature involving naturalness, smoothness, and variation in stroke pressure, aiding in distinguishing genuine from forged handwriting.

9. Which of the following best explains the increased mitochondrial DNA (mtDNA) success rate in degraded forensic samples?

A) Its circular structure enables better amplification

B) Higher mutation rate increases allele variability

C) Its abundance per cell is significantly higher than nuclear DNA

D) It undergoes less chemical degradation than nuclear DNA

Answer: C) Its abundance per cell is significantly higher than nuclear DNA

Explanation: mtDNA exists in thousands of copies per cell, enhancing recovery from degraded or minimal biological materials (e.g., hair shafts, bones).

 

10. Which method is best suited to differentiate between genuine and forged ink entries made at different times on the same document?

A) Oblique lighting

B) ESDA

C) Infrared Reflectance Spectroscopy

D) Thin Layer Chromatography

Answer: C) Infrared Reflectance Spectroscopy

Explanation: Infrared reflectance can detect chemical differences in ink, allowing visualization of additions or alterations made at different times, especially with inks that are visually similar.

Content Writer:- Srishti Dutta