which structure in the skin is responsible for producing melanin

ATI TEAS 7

Practice Science TEAS Test

1. Which structure in the skin is responsible for producing melanin?

A. Sudoriferous gland
B. Melanocyte
C. Sebaceous gland
D. Hair follicle

Correct answer: B

Rationale: The correct answer is B: Melanocyte. Melanocytes in the skin are responsible for producing melanin, the pigment that gives skin its color and provides protection against harmful UV radiation. Sudoriferous glands produce sweat, sebaceous glands produce sebum (oil), and hair follicles are associated with hair growth. However, the specific function of producing melanin is attributed to melanocytes, making them the correct answer in this context.

2. What phenomenon explains the formation of rainbows in the sky?

A. Diffraction
B. Interference
C. Refraction and dispersion of sunlight by water droplets
D. Reflection from clouds

Correct answer: C

Rationale: Rainbows are formed due to the refraction and dispersion of sunlight by water droplets in the atmosphere. When sunlight enters a water droplet, it is refracted, then internally reflected, and finally refracted again as it exits the droplet. This dispersion of light into its component colors creates the beautiful rainbow we see in the sky. Choice A, diffraction, involves bending of light around obstacles or through narrow openings, not the splitting of light into colors as seen in rainbows. Choice B, interference, refers to the phenomenon where two or more light waves overlap and interact, producing a pattern of light and dark bands, which is not the case with rainbows. Choice D, reflection from clouds, does not accurately describe the process involved in the formation of rainbows through refraction and dispersion of light by water droplets.

3. What is the primary function of nervous tissue?

A. Movement
B. Protection
C. Communication and coordination
D. Nutrient transport

Correct answer: C

Rationale: The primary function of nervous tissue is communication and coordination within the body. Nervous tissue is composed of neurons that transmit electrical signals and supporting cells known as neuroglia. Movement is primarily controlled by the muscular system, protection is mainly provided by the skeletal system and immune system, and nutrient transport is carried out by the circulatory system. Therefore, choices A, B, and D are incorrect as they do not align with the primary function of nervous tissue.

4. What are chromosomes made of?

A. DNA and RNA
B. DNA and protein
C. Protein and RNA
D. DNA and lipids

Correct answer: B

Rationale: Chromosomes are made up of DNA and associated proteins. These proteins help package and organize the DNA within the cell, playing a crucial role in gene regulation and cell division. While RNA is involved in various cellular processes, it is not a primary component of chromosomes. Lipids are not a fundamental component of chromosomes, which primarily consist of DNA and proteins.

5. Which of the following constituents of blood is a biconcave disc that is round and flat without a nucleus?

A. Plasma
B. Platelet
C. RBC
D. WBC

Correct answer: C

Rationale: The correct answer is C, RBC (Red Blood Cell). Red blood cells are biconcave discs that lack a nucleus, allowing them to carry oxygen efficiently. Plasma (A) is the liquid component of blood that carries various substances. Platelets (B) are cell fragments important for blood clotting. White blood cells (WBCs) (D) are part of the immune system and have a nucleus.