Questions Set-5: Forensic Biology

Q1. Which of the following microscopic features is most useful for distinguishing between hair from different racial groups?

a.       Medullary index

b.      Cortex pigmentation

c.       Cuticle pattern

d.      Root

ANSWER:

c. Cuticle pattern

EXPLANATION:

The cuticle pattern, which consists of the scale-like structures on the outer layer of the hair shaft, is often used to distinguish between hair from different racial groups. Differences in the cuticle pattern can be observed under a microscope and can vary among individuals of different ethnic backgrounds.

Q2. What is the primary advantage of using Scanning Electron Microscopy (SEM) for hair analysis?

a.       Analyse chemical composition of hair dyes

b.      Provides details for hair’s surface structure

c.       Determines chronological age of hair sample

d.      Extract and amplify DNA from roots

ANSWER:

b. provides details for hair’s surface structure

EXPLANATION:

Scanning Electron Microscopy (SEM) is advantageous in hair analysis because it provides high-resolution images of the hair’s surface structure, including the cuticle pattern and any damage or treatment effects.

Q3. Which characteristic of the medulla in hair analysis can help forensic scientists determine if the hair is from a human or an animal?

a.      Medullary index

b.      Medullary pattern

c.       Medullary shape

d.      Shaft color

ANSWER:

b. Medullary pattern

EXPLANATION:

The medullary pattern (whether it is continuous, fragmented, or absent) helps to differentiate between human and animal hair. Animal hair often has a more continuous medullary pattern, while human hair typically shows a fragmented or absent medulla.

Q4. In which phase of the hair growth cycle is DNA analysis most likely to yield the highest quality results?

a.      Anagen phase

b.      Catagen phase

c.       Telogen phase

d.      Exogen phase

ANSWER:

a.       Anagen phase

EXPLANATION:

The anagen phase, or growth phase, is when the hair is actively growing and has the most robust and intact root structure, which provides the highest quality DNA for analysis. In contrast, hair in the telogen or exogen phases may have degraded DNA or be more susceptible to contamination.

Q5. What type of hair sample provides the most conclusive evidence in terms of DNA profiling for forensic analysis?

a.      A hair sample from middle of the shaft

b.      A hair sample with visible damage without root

c.       A hair sample with intact root

d.      A hair sample without root

ANSWER:

c. A hair sample with intact root

 EXPLANATION:

A hair sample with the root intact provides the most conclusive evidence for DNA profiling because it contains the follicular tissue, which is rich in nuclear DNA. This allows for more accurate and reliable DNA analysis compared to hair without the root or only the hair shaft, which may have degraded or less accessible DNA.

Q6. How does the refractive index of a fiber contribute to forensic analysis?

a.      It helps in matching the chemical composition of fibers

b.      It allows for the comparison of fibers based on their optical behavior in different media

c.       It determines the fiber’s physical strength

d.      It indicates the fiber’s dye concentration

ANSWER:

b. it allows for the comparison of fibers based on their optical behavior in different media

EXPLANATION:

The refractive index of a fiber is crucial for forensic analysis as it helps in comparing fibers based on their optical behavior when placed in different media (e.g., glass or oil). By measuring how light refracts through a fiber, forensic scientists can determine if fibers are consistent with those found at a crime scene or on a suspect’s clothing.

Q7. What type of fibers is particularly challenging to analyze due to their small size and similarity to other fibers?

a.      Microfibers

b.      Natural fibers

c.       Man-made fibers

d.      Animal fibers

ANSWER:

a.       Micro-fibers

EXPLANATION:

Microfibers are particularly challenging to analyze due to their small size and the fact that they often have similar characteristics to other fibers. Their small diameter can make them difficult to detect and analyze accurately, requiring specialized techniques and equipment for reliable identification.

Q8. Which type of analysis is best suited for determining if a hair has been subjected to chemical treatments, such as dyeing or perming?

a.      Microscopic analysis of cuticle and cortex

b.      DNA analysis from hair root

c.       Elemental analysis using ICP-MS

d.      Analysis of medullary index and pattern

ANSWER:

a.       Microscopic analysis of cuticle and cortex

EXPLANATION:

Dyeing or perming often changes the cuticle’s appearance. For example, chemical treatments may cause the cuticle scales to become lifted, flattened, or irregular. Dyeing can also lead to the accumulation of colorants on the cuticle surface, while perming can cause the cuticle to look more damaged or worn. Chemical treatments can affect the distribution and concentration of pigment in the cortex, which may be visible as alterations in texture or color distribution under a microscope.

Q9. Assertion A: High-Performance Liquid Chromatography (HPLC) is a standard method for analyzing the dye composition in fibers.

Reason R: HPLC can separate and identify the chemical components of dyes used in fibers.

a.      Both A and R are correct and R is the correct explanation of A

b.      Both A and R are correct but R is NOT the correct explanation of A

c.       A is correct but R is not correct

d.      A is not correct but R is correct

ANSWER:

a.       Both A and R are correct and R is the correct explanation of a

EXPLANATION:

High-Performance Liquid Chromatography (HPLC) is commonly used for analyzing dye compositions in fibers because it effectively separates and identifies the chemical components, helping to match fibers from a crime scene to specific sources.

Q10. Assertion A: Mitochondrial DNA analysis is less discriminative than nuclear DNA analysis in hair forensic cases.

Reason R: Mitochondrial DNA is inherited maternally and is common among individuals from the same maternal lineage, making it less unique.

e.      Both A and R are correct and R is the correct explanation of A

f.        Both A and R are correct but R is NOT the correct explanation of A

g.       A is correct but R is not correct

h.      A is not correct but R is correct

ANSWER:

a.       Both A and R are correct and R is the correct explanation of A

EXPLANATION:

Mitochondrial DNA is less discriminative than nuclear DNA because it is inherited maternally and can be shared among individuals within the same maternal lineage. However, it is still useful when nuclear DNA is not available, such as in hair shafts without roots.

Content Writer:- Bhawna Sharma