Hair Analysis Quiz

Where in the hair structure is DNA primarily found for forensic analysis?

• Throughout the hair shaft

• In the hair follicle

• In the cuticle layer only

• In the medulla only

Answer explanation

DNA is primarily found in the hair follicle, which is the part of the hair that is embedded in the skin. This area contains living cells that can provide genetic material for forensic analysis.

Why is the physical examination of hair considered class evidence rather than individual evidence?

• Because hair is not unique to a specific individual

• Because hair cannot be collected at crime scenes

• Because hair does not contain DNA

• Because hair analysis requires specialized equipment

Answer explanation

Hair is considered class evidence because it lacks unique characteristics that can definitively link it to a specific individual. Many people can share similar hair traits, making it less reliable for individual identification.

What is the average rate of hair growth per month?

• 0.1-0.2 inches

• 0.3-0.5 inches

• 0.8-1.0 inches

• 1.5-2.0 inches

Answer explanation

The average rate of hair growth is typically between 0.3 to 0.5 inches per month, making this the correct choice. Other options are either too low or too high compared to the average growth rate.

Which microscope type allows forensic scientists to view two hair samples simultaneously for direct comparison?

• electron microscope

• stereo microscope

• compound microscope

• comparison microscope

Answer explanation

The comparison microscope is specifically designed to allow forensic scientists to view two samples, such as hair, side by side for direct comparison, making it the correct choice for this task.

Which of the following is NOT one of the three layers of the hair shaft?

• medulla

• cortex

• cuticle

• papilla

Answer explanation

The hair shaft consists of three layers: the medulla, cortex, and cuticle. The papilla, however, is not a layer of the hair shaft; it is part of the hair follicle that nourishes the hair.

What characteristic of hair allows forensic scientists to distinguish between human and cat hair?

• hair color

• cuticle pattern

• length of hair

• hair diameter

Answer explanation

The cuticle pattern is a key characteristic that differentiates human hair from cat hair. Humans have a different scale pattern on the cuticle compared to cats, making it a reliable feature for forensic analysis.

**Which of the following best explains why carbon-based compounds like keratin in hair are important in forensic science?

• Carbon compounds are always unique to each individual

• Carbon compounds can only be found in human hair

• Carbon's ability to form diverse compounds creates distinctive structural properties

• Carbon compounds are resistant to degradation in all environmental conditions

Answer explanation

Carbon's ability to form diverse compounds allows for a wide range of structural properties in keratin, making it distinctive and useful in forensic science for identifying individuals.

What is the medullary index in hair analysis?

• A measurement of hair growth rate

• The ratio of the medulla diameter to the overall hair shaft diameter

• The pattern of pigment distribution in the cortex

• The number of scales present on the cuticle surface

Answer explanation

The medullary index is defined as the ratio of the medulla diameter to the overall hair shaft diameter, making it a key measurement in hair analysis for identifying species and individual characteristics.

Which observation about two hair samples would provide the strongest evidence that they came from different sources?

• slight difference in hair color

• different medulla patterns

• different cuticle scale patterns

• slight difference in hair diameter

Answer explanation

Different cuticle scale patterns provide the strongest evidence of different sources because they are unique to individual hair types, unlike slight color or diameter differences which can be more variable.

Which microscopic feature contains the pigment granules that determine hair color?

• medulla

• cortex

• cuticle

• follicle

Answer explanation

The cortex is the layer of hair that contains pigment granules, which are responsible for determining hair color. The medulla is the innermost layer, the cuticle is the outer layer, and the follicle is the hair root structure.

Tags

NGSS.HS-LS3-2