Nursing Elites

1. Which of the following neurotransmitters slows down the activity of neurons, preventing them from becoming overexcited?

• A. Acetylcholine
• B. Dopamine
• C. GABA
• D. Serotonin

Correct answer: C

Rationale: The correct answer is C: GABA (gamma-aminobutyric acid). GABA acts as an inhibitory neurotransmitter that reduces neuronal activity, thus preventing overexcitation. Acetylcholine (choice A) is involved in muscle control and cognitive function, but it is not primarily responsible for slowing down neuronal activity. Dopamine (choice B) plays a role in reward-motivated behavior and motor control, rather than inhibiting neuronal firing. Serotonin (choice D) is involved in mood regulation, sleep, and appetite but does not primarily slow down neuronal activity to prevent overexcitation.

2. What is the difference between homologous chromosomes and sister chromatids?

• A. Homologous chromosomes have the same genes but may have different alleles, while sister chromatids are identical copies of the same chromosome.
• B. Homologous chromosomes are only found in diploid cells, while sister chromatids are found in both haploid and diploid cells.
• C. Both homologous chromosomes and sister chromatids are genetically identical, but only sister chromatids separate during mitosis.
• D. Both homologous chromosomes and sister chromatids can separate during mitosis, but only homologous chromosomes have different alleles.

Correct answer: A

Rationale: Rationale: - Homologous chromosomes are pairs of chromosomes that have the same genes in the same order, one from each parent. While they carry the same genes, they may have different alleles (variants of a gene). - Sister chromatids are exact copies of each other, formed during DNA replication. They are held together by a centromere and are produced during the S phase of the cell cycle. - During meiosis, homologous chromosomes pair up and exchange genetic material through crossing over, leading to genetic variation. Sister chromatids separate during mitosis to ensure each daughter cell receives an identical copy of the genetic material.

3. What are stem cells that can develop into many different cell types, but not a complete organism, known as?

• A. Totipotent stem cells
• B. Multipotent stem cells
• C. Pluripotent stem cells
• D. Hematopoietic stem cells

Correct answer: C

Rationale: Pluripotent stem cells are capable of developing into many different cell types, but they cannot form a complete organism. Totipotent stem cells have the ability to give rise to all cell types in an organism, including extraembryonic tissues, enabling them to form a complete organism. Multipotent stem cells can differentiate into a limited range of cell types. Hematopoietic stem cells specifically give rise to blood cells.

4. What is a benefit of a taxonomic system?

• A. Researchers can describe how living things behave.
• B. Researchers can develop names for new organisms.
• C. Living things can be distinguished from nonliving things.
• D. Living things can be classified based on their molecular traits.

Correct answer: D

Rationale: The correct answer is D. A taxonomic system allows scientists to classify living organisms based on their molecular and genetic traits. This classification helps in understanding the relationships and evolutionary history of different organisms, providing insights into their characteristics and behaviors. Choices A, B, and C do not directly relate to the primary purpose and benefit of a taxonomic system, which is the systematic classification of organisms.

5. Centrioles are structures involved in cell division. What is their specific role?

• A. Forming the nuclear envelope
• B. Replicating DNA
• C. Organizing microtubules during cell division
• D. Protein synthesis

Correct answer: C

Rationale: Centrioles are involved in organizing microtubules during cell division, specifically in forming the mitotic spindle. The mitotic spindle is crucial for the proper alignment and separation of chromosomes during cell division, ensuring the accurate distribution of genetic material to daughter cells. Choice A, forming the nuclear envelope, is incorrect as centrioles do not have a direct role in this process. Choice B, replicating DNA, is incorrect as centrioles are not involved in DNA replication. Choice D, protein synthesis, is incorrect as centrioles do not play a role in protein synthesis.

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