Nursing Elites

1. What is involved in the involuntary reflex arc that withdraws your hand from a hot object?

• A. Central nervous system only
• B. Peripheral nervous system only
• C. Both CNS and PNS
• D. Sensory neurons only

Correct answer: C

Rationale: The involuntary reflex arc that withdraws your hand from a hot object involves both the central nervous system (CNS) and the peripheral nervous system (PNS). When your hand touches a hot object, sensory neurons in the PNS detect the heat and send signals to the spinal cord in the CNS. The spinal cord processes this information and sends a signal back through motor neurons in the PNS to move your hand away from the hot object. This coordinated response requires the collaboration of both the CNS and PNS to protect the body from harm. Choice A is incorrect because the reflex arc involves more than just the central nervous system. Choice B is incorrect because the reflex arc involves more than just the peripheral nervous system. Choice D is incorrect because the reflex arc also involves motor neurons, not just sensory neurons.

2. What is the role of the spindle apparatus in cell division?

• A. To separate sister chromatids
• B. To move chromosomes to opposite poles of the cell
• C. To form a new nuclear envelope around each daughter cell
• D. To synthesize new DNA

Correct answer: B

Rationale: The spindle apparatus, composed of microtubules, plays a crucial role in cell division (mitosis and meiosis) by ensuring proper chromosome separation and distribution to opposite poles of the cell. This segregation is vital for creating two genetically identical daughter cells in mitosis or four haploid daughter cells in meiosis. Choice A is incorrect because the separation of sister chromatids is specifically carried out by kinetochore fibers within the spindle apparatus. Choice C is inaccurate as the formation of a new nuclear envelope occurs post chromosome segregation. Choice D is incorrect as DNA synthesis does not occur within the spindle apparatus; it takes place during the S phase of the cell cycle.

3. What is a submicroscopic entity that is considered nonliving because it lacks cellular structure and consists of nucleic acids encapsulated in a protein coat called a capsid?

• A. Bacteria
• B. Fungus
• C. Virus
• D. Protozoa

Correct answer: C

Rationale: The correct answer is C: Virus. Viruses are not considered living organisms because they lack cellular structure. Instead, they are composed of nucleic acids (either DNA or RNA) enclosed in a protein coat called a capsid. Bacteria (choice A), fungus (choice B), and protozoa (choice D) are all living organisms with cellular structures, unlike viruses. Therefore, they are incorrect choices for this question.

4. Where are most of the body's immune cells located?

• A. Blood
• B. Brain
• C. Skin
• D. Large intestine

Correct answer: A

Rationale: - The majority of the body's immune cells are located in the blood. Immune cells, such as white blood cells (leukocytes), circulate throughout the body via the bloodstream to detect and fight off infections and foreign invaders. - While immune cells are also present in other parts of the body like the lymph nodes, spleen, and bone marrow, the blood serves as a primary conduit for immune cells to travel to different tissues and organs to carry out their functions. - The brain (option B) is protected by the blood-brain barrier, which limits the entry of immune cells into the brain to prevent inflammation and damage. - The skin (option C) contains immune cells like Langerhans cells that help protect against pathogens, but the largest concentration of immune cells is found in the blood. - The large intestine (option D) also houses a significant amount of immune cells due to its role in interacting with the external environment through the gut-associated lymphoid tissue, but the primary location for most of the body's immune cells is the blood.

5. In meiosis, how many divisions occur, and how many daughter cells are produced?

• A. One division, two daughter cells
• B. Two divisions, four daughter cells
• C. Four divisions, eight daughter cells
• D. Eight divisions, sixteen daughter cells

Correct answer: B

Rationale: In meiosis, there are two divisions: meiosis I and meiosis II. During meiosis I, homologous chromosomes separate, resulting in two daughter cells with half the number of chromosomes as the parent cell. In meiosis II, sister chromatids separate, resulting in a total of four daughter cells, each with a haploid set of chromosomes. Therefore, meiosis involves two divisions and produces four daughter cells. Choice A is incorrect because meiosis involves two divisions, not one. Choice C and D are incorrect as meiosis does not go through four or eight divisions, resulting in eight or sixteen daughter cells.

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