UGC NTA NET/JRF Exam, Forensic Science, June-2025

Alcohol is metabolized in the liver primarily through three pathways:

Alcohol dehydrogenase pathway (B): The main enzymatic route, converting ethanol to acetaldehyde.

Microsomal ethanol oxidizing system (D): Involves cytochrome P450 2E1, active at higher concentrations of ethanol.

Peroxidase catalase system (E): A minor pathway, using catalase and hydrogen peroxide to oxidize ethanol.

The central cholinergic pathway (A) is unrelated, and cytochrome P450 (C) is part of the MEOS system but not listed separately in this context.

Firearm cartridge cases are mainly made of brass, an alloy of copper and zinc. Both copper (atomic number 29) and zinc (atomic number 30) belong to the d-block (transition metals) of the periodic table.

These metals provide the strength, malleability, and resistance to corrosion required for cartridge cases.

When two ink lines cross, the darker line often appears to be on top, regardless of which was written first.

This is a classic optical illusion in questioned document examination. It can mislead the examiner, and special techniques (like microscopy or electrostatic methods) are used to determine the actual sequence of strokes.

The filing system of fingerprint record slips used by the National Crime Records Bureau (NCRB) follows the principles of Henry's Classification System. The order of arrangement is very structured so that every record can be quickly located in the central database. The steps are:

A. Primary classification: This is the first iand most basic division, based on the presence or absence of whorls in specific fingers. It provides the broadest level of sorting.

C. Secondary classification: Within each primary group, further subdivision is done using the pattern types (loops, whorls, arches) of specific fingers. This narrows down the search field.

B. Major classification: At this stage, ridge counts are considered for particular fingers (commonly thumbs or index fingers). This allows for more precise grouping within the secondary classes.

E. Sub-secondary classification (1, 2, or 3 if any): These are finer gradations based on ridge tracing and other features. They serve as additional layers of organization to further reduce the number of possible matches.

D. Final classification: This is the last step, which takes into account unique ridge counts or other details of specific fingers, giving a complete index reference for filing and retrieval.

Thus, the correct chronological filing sequence is: Primary → Secondary → Major → Subsecondary → Final.

In forensic document analysis, interlineation refers to inserting new writing or typing between two existing lines of text.

It is a common alteration technique in fraudulent documents. Addition is general insertion, restoration means bringing back erased writing, and decipherment refers to reading obscured or hidden writing.

To determine the range of fire, forensic experts carefully study the effects of firing residues and physical marks left on the target.

Each effect occurs only within a certain distance, so by analyzing them, the approximate firing distance can be established. Forensic Indicators by Range (Nearest→ Farthest)

B. Muzzle pattern (Contact shot): Appears only when the firearm is pressed firmly against the body or clothing. The hot gases and residues force an imprint of the muzzle's shape on the skin or fabric. Often seen in suicide cases or point-blank shootings.

C. Scorching (Close range): Caused by the flame and hot gases emitted from the muzzle. Produces burns or singeing of skin, hair, or clothing. Occurs at very short distances (within a few centimeters).

E. Blackening (Short range): Deposition of smoke and soot particles around the entry wound. Indicates a shot fired from a slightly greater distance than scorching but still close range. Produces a dark, smudgy area around the wound.

D. Tattooing (Intermediate range): Unburnt and partially burnt powder particles strike the skin and embed in it. Produces small punctate reddish-brown abrasions known as stippling. Seen at distances up to ~60-90 cm depending on the firearm and ammunition used.

A. Metallic residue (Far range): Trace elements such as lead, barium, and antimony from the primer and bullet are deposited. Not visible to the naked eye but can be detected using chemical tests (e.g., dermal nitrate test, atomic absorption spectrophotometry, or SEM-EDX). Can still be found even when no visible effects like blackening or tattooing remain.

А. Нard prodrug (II): A biologically active compound designed with high stability and long half-life, often highly lipid- or water-soluble, that remains in the body for prolonged periods.

B. Soft prodrug (I): A biologically active compound deliberately designed to be rapidly and predictably broken down into inactive, non-toxic metabolites, minimizing accumulation and toxicity.

C. Carrier-linked prodrug (IV): Consists of an active drug molecule attached to a carrier group that is cleaved enzymatically to release the active drug.

D. Mutual prodrug (III): Two synergistic drugs linked together chemically, so that both contribute to therapeutic action after cleavage.

Blood droplet formation is governed by physical properties and forces:
• Viscosity: Determines internal resistance to flow.
• Surface tension: Causes the droplet to assume a spherical shape.
• Gravity: Pulls the droplet downward, enabling its detachment and fall.

Adhesive force, however, relates to the attraction between blood and a surface. While it may influence how blood sticks to a substrate after falling, it is not a direct factor in the initial formation of a free-falling droplet.

The number of pellets per ounce (28.35 g) is standardized for different shotgun shot sizes:
A. A-shot (III): ~50 pellets.
B. SG-shot (II):~8 pellets.
C. B-shot (IV): ~80 pellets.
D. SSG-shot (I):~15 pellets.
This classification helps in identifying the type of cartridge used in a case.

А. Class characteristics (IV): Common features resulting from similar training, education, or writing systems (e.g., letter forms taught in a specific school).

B. Individual characteristics (I): Unique, personal handwriting traits that serve as the backbone of identification, such as unusual slants, spacing, or letter formations.

C. Writing standards (II): Authentic, known handwriting samples that are used as the basis of comparison in document examination.

D. Writing variation (III): Natural differences that occur when the same writer produces multiple writings, considered an integral part of natural handwriting.