which of the following is part of the central nervous system

ATI TEAS 7

Practice Science TEAS Test

1. Which of the following is part of the central nervous system?

A. Spinal cord
B. Peripheral nerves
C. Brainstem
D. Cerebellum

Correct answer: A

Rationale: The correct answer is A: Spinal cord. The central nervous system comprises the brain and spinal cord. The spinal cord plays a crucial role in transmitting information between the brain and the body. Choices B, C, and D are not part of the central nervous system. Peripheral nerves belong to the peripheral nervous system, whereas the brainstem and cerebellum are components of the brain, distinct from the central nervous system.

2. How do DNA and RNA function together as part of the human genome?

A. DNA carries genetic information from RNA to the cell cytoplasm.
B. RNA carries genetic information from DNA to the cell cytoplasm.
C. DNA and RNA carry genetic information from the cell nucleus to the cytoplasm.
D. DNA and RNA do not interact within the cell.

Correct answer: B

Rationale: The correct answer is B. RNA acts as a messenger carrying genetic instructions from the DNA in the nucleus to the cytoplasm, where proteins are synthesized. This process is known as transcription and translation, where DNA provides the blueprint for protein synthesis, and RNA delivers this information to the cellular machinery in the cytoplasm. Choice A is incorrect as it inaccurately states that DNA carries genetic information from RNA, which is the opposite of the actual flow of information. Choice C is incorrect as it suggests that both DNA and RNA together carry genetic information from the nucleus to the cytoplasm, which is not accurate. Choice D is incorrect as DNA and RNA do interact within the cell, playing crucial roles in genetic information processing and protein synthesis.

3. How can a single gene mutation lead to multiple phenotypes depending on the organism?

A. Pleiotropy describes the effect of one gene influencing multiple seemingly unrelated traits.
B. Epigenetics involves environmental factors modifying gene expression without altering the DNA sequence.
C. Genetic drift refers to random changes in allele frequencies within a population.
D. Gene regulation controls the timing and level of gene expression within an organism.

Correct answer: A

Rationale: A single gene mutation can lead to multiple phenotypes through pleiotropy, where one gene influences diverse traits or functions in an organism. This phenomenon occurs when the mutated gene affects different biochemical pathways, developmental processes, or cellular functions, resulting in a cascade of downstream effects that manifest as a variety of phenotypic outcomes. Choice B, epigenetics, involves modifications in gene expression influenced by environmental factors without altering the DNA sequence, which is not directly related to the question about single gene mutations causing multiple phenotypes. Choice C, genetic drift, refers to random changes in allele frequencies within a population, which is unrelated to the impact of a single gene mutation on multiple phenotypes. Choice D, gene regulation, focuses on controlling the timing and level of gene expression within an organism, which is not directly addressing how a single gene mutation can lead to diverse phenotypes.

4. What is the term for a group of organisms with the same genetic makeup?

A. Population
B. Clone
C. Genotype
D. Species

Correct answer: B

Rationale: In this context, a clone (option B) is a group of organisms that are genetically identical because they are derived from a single ancestor. A population (option A) refers to a group of individuals of the same species living in the same area. Genotype (option C) refers to the genetic makeup of an individual organism. Species (option D) refers to a group of organisms that can interbreed and produce fertile offspring. Therefore, the most appropriate choice for the question is 'Clone,' as it specifically refers to organisms with the same genetic makeup.

5. Which of the following is an example of stabilizing selection?

A. Selection that favors extreme traits in a population
B. Selection that removes individuals with extreme traits
C. Selection that maintains the current average trait in a population
D. Selection that favors one specific trait over all others

Correct answer: C

Rationale: - Stabilizing selection is a type of natural selection that favors the intermediate variants in a population, while selecting against the extreme traits. This results in the maintenance of the current average trait in the population. - Option A is incorrect because stabilizing selection does not favor extreme traits; instead, it favors the average trait. - Option B is incorrect because stabilizing selection does not remove individuals with extreme traits; it acts against extreme traits by favoring the intermediate variants. - Option D is incorrect because stabilizing selection does not favor one specific trait over all others; it favors the average trait by selecting against extreme traits.