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. Which term refers to the resistance of a liquid to flow?

A. Density
B. Viscosity
C. Surface tension
D. Boiling point

Correct answer: B

Rationale: Viscosity is the term that refers to the resistance of a liquid to flow. It is a measure of how thick or sticky a fluid is and determines how easily a liquid can flow. Density (A) is a measure of how much mass is contained in a given volume and is not related to the resistance of a liquid to flow. Surface tension (C) is the property of a liquid that allows it to resist an external force due to the cohesive nature of its molecules, but it is not directly related to the resistance of a liquid to flow. Boiling point (D) is the temperature at which a liquid changes to a vapor and is not a measure of the resistance of a liquid to flow.

3. Two identical balls, one made of clay and the other made of steel, are dropped from the same height. Which ball reaches the ground first, neglecting air resistance?

A. The clay ball due to its lower density
B. The steel ball due to its higher density
C. Both balls reach the ground simultaneously
D. It depends on the initial velocities of the balls

Correct answer: C

Rationale: In the absence of air resistance, both balls will experience the same acceleration due to gravity (9.8 m/s^2) regardless of their densities or materials. This means that both balls will reach the ground at the same time, assuming they are dropped from the same height simultaneously. The differences in density or material composition do not affect the rate at which objects fall in a vacuum. Therefore, both the clay and steel balls, being identical in shape and starting position, will have the same free-fall acceleration and will hit the ground simultaneously. Choices A and B are incorrect because the density of the materials does not impact the time it takes for objects to fall under gravity alone. Choice D is incorrect as the initial velocities do not play a role in the time taken to fall in a vacuum, where only the acceleration due to gravity affects the motion.

4. Classifications of human tissues exclude:

A. Epithelial tissue
B. Nervous tissue
C. Adipose tissue (a specialized form of connective tissue)
D. Bony tissue

Correct answer: D

Rationale: The correct answer is D: Bony tissue. Classifications of human tissues typically include epithelial tissue, nervous tissue, and connective tissue types such as adipose tissue. Bony tissue, also known as bone tissue, is a specialized form of connective tissue that provides structural support and protection for the body. Therefore, it is not excluded from classifications of human tissues. Choices A, B, and C are valid types of human tissues and are correctly included in classifications of human tissues.

5. What checkpoint mechanism ensures all chromosomes are attached to the spindle fibers before anaphase begins?

A. Prometaphase
B. Metaphase
C. Cyclin degradation
D. Sister chromatid cohesion

Correct answer: A

Rationale: A) Prometaphase is the correct answer because it is the stage of mitosis where all chromosomes are attached to the spindle fibers before anaphase begins. During prometaphase, the nuclear envelope breaks down, allowing the spindle fibers to attach to the kinetochores of the chromosomes. This attachment is necessary for proper chromosome alignment and segregation during anaphase. B) Metaphase is incorrect because it is the stage where chromosomes are aligned at the metaphase plate but do not necessarily have all spindle fibers attached. C) Cyclin degradation is incorrect because it is a regulatory mechanism that controls the progression of the cell cycle but is not specifically related to ensuring all chromosomes are attached to spindle fibers. D) Sister chromatid cohesion is incorrect because it refers to the physical connection between sister chromatids that is maintained until anaphase, but it does not ensure that all chromosomes are attached to spindle fibers.