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 of the following is an example of a pivot joint?

A. Hip
B. Neck
C. Shoulder
D. Elbow

Correct answer: B

Rationale: The correct answer is B: Neck. A pivot joint, as found in the neck, allows for rotational movement around a single axis. This type of joint is essential for movements like shaking your head 'no' or looking left and right. Choices A, C, and D are incorrect because the hip, shoulder, and elbow joints are examples of ball-and-socket joints, which allow for a wide range of motion in multiple directions, not just rotational movement around a single axis like a pivot joint.

3. Describe the mechanism by which genes are transmitted from parents to offspring.

A. Blending of parental genes, resulting in an average of their traits.
B. Random assortment of alleles during meiosis, leading to unique combinations in each offspring.
C. Inheritance of solely dominant alleles, masking the influence of recessive ones.
D. Direct transfer of both parental genomes, creating identical copies of the parents.

Correct answer: B

Rationale: A) Blending of parental genes, resulting in an average of their traits, is not an accurate description of how genes are transmitted. In reality, genes are not blended but rather passed down in discrete units. B) Random assortment of alleles during meiosis is the correct mechanism by which genes are transmitted from parents to offspring. During meiosis, homologous chromosomes separate, and alleles are randomly distributed to the gametes, leading to unique combinations of genes in each offspring. C) Inheritance of solely dominant alleles, masking the influence of recessive ones, is not an accurate representation of gene transmission. Offspring inherit alleles from both parents, and the expression of dominant or recessive traits depends on the specific combination of alleles. D) Direct transfer of both parental genomes, creating identical copies of the parents, is not how genes are transmitted. Offspring inherit a unique combination

4. Which of the following correctly describes mitosis?

A. Mitosis occurs in germ cells.
B. Mitosis occurs in somatic cells.
C. Mitosis involves the reduction of chromosome number by half.
D. Mitosis produces four genetically different cells.

Correct answer: B

Rationale: The correct answer is B. Mitosis occurs in somatic cells where a single cell divides to produce two identical daughter cells. Germ cells undergo meiosis, not mitosis. Choice C is incorrect as mitosis results in the preservation of the same chromosome number in daughter cells. Choice D is inaccurate as mitosis produces genetically identical cells, not genetically different ones.

5. Which of the following is a characteristic of an interneuron?

A. Forms neural circuits
B. Interacts with effectors
C. Sends impulses to the CNS
D. Functions as an efferent nerve cell

Correct answer: A

Rationale: The correct characteristic of an interneuron is that it forms neural circuits, connecting sensory and motor neurons within the central nervous system. Interneurons facilitate communication between different neurons in the central nervous system, helping in the processing and integration of signals. Choice B is incorrect as interneurons primarily interact with other neurons, not effectors. Choice C is incorrect as interneurons typically do not send impulses to the CNS; they operate within the CNS. Choice D is incorrect as interneurons are not efferent nerve cells; they are mainly involved in processing signals within the CNS rather than transmitting signals to effectors.