Nursing Elites

1. Where does the electron transport chain occur in the cell?

• A. Cytosol
• B. Golgi apparatus
• C. Inner mitochondrial membrane
• D. Nucleus

Correct answer: C

Rationale: The electron transport chain occurs in the inner mitochondrial membrane. This process is crucial for the generation of ATP, the cell's energy currency. Choice A (Cytosol) is incorrect as the electron transport chain does not take place in the cytosol. Choice B (Golgi apparatus) is also incorrect as the Golgi apparatus is involved in modifying, sorting, and packaging of proteins. Choice D (Nucleus) is incorrect as the nucleus houses the cell's genetic material but is not the location of the electron transport chain.

2. Which cells myelinate neurons in the PNS?

• A. Oligodendrocytes
• B. Astrocytes
• C. Schwann cells
• D. Microglia

Correct answer: C

Rationale: Schwann cells are the glial cells responsible for myelinating neurons in the peripheral nervous system (PNS). They form the myelin sheath around axons, which helps in the conduction of electrical impulses. Oligodendrocytes, on the other hand, myelinate neurons in the central nervous system (CNS). Astrocytes primarily provide support for neuronal function by regulating the chemical environment around neurons and maintaining the blood-brain barrier. Microglia are part of the immune response in the CNS, where they act as the resident macrophages, playing a role in immune surveillance and response to injury or disease. Therefore, the correct answer is Schwann cells (Choice C) as they specifically myelinate neurons in the PNS, differentiating them from the other cell types mentioned in the choices.

3. What does the T wave on an ECG correspond to?

• A. Atrial depolarization
• B. Ventricular depolarization
• C. Atrial repolarization
• D. Ventricular repolarization

Correct answer: D

Rationale: The T wave on an ECG corresponds to ventricular repolarization. Following ventricular depolarization, which is represented by the QRS complex, the ventricles undergo repolarization during the T wave. This phase signifies the recovery of ventricular muscle cells as they prepare for the subsequent depolarization cycle. Choices A, B, and C are incorrect because the T wave specifically reflects the repolarization of the ventricles, not the atria or their respective depolarization or repolarization phases.

4. Which types of glial cells are found in the CNS?

• A. Schwann cells, satellite cells
• B. Astrocytes, microglia, ependymal cells, oligodendrocytes
• C. Satellite cells, microglia, oligodendrocytes
• D. Astrocytes, Schwann cells, satellite cells

Correct answer: B

Rationale: The correct answer is B. Glial cells in the CNS include astrocytes, microglia, ependymal cells, and oligodendrocytes. Schwann cells and satellite cells are found in the PNS. Astrocytes are the most abundant type of glial cells and are involved in nutrient support, repair, and maintenance of the extracellular environment. Microglia are the resident immune cells of the CNS, playing a role in immune defense. Ependymal cells line the ventricles of the brain and the central canal of the spinal cord, contributing to the production and circulation of cerebrospinal fluid. Oligodendrocytes are responsible for producing myelin, which insulates axons in the CNS. Understanding the specific functions of each type of glial cell is essential in grasping the complexity of the central nervous system's support and protective mechanisms.

5. How are sister chromatids distinguished from homologous chromosomes in meiosis I?

• A. Sister chromatids share the same centromere, while homologous chromosomes have different centromeres.
• B. Sister chromatids have identical DNA sequences, while homologous chromosomes have slightly different sequences due to crossing over.
• C. Sister chromatids repel each other, while homologous chromosomes attract each other during synapsis.
• D. Sister chromatids separate during anaphase I, while homologous chromosomes separate during anaphase II.

Correct answer: B

Rationale: In meiosis I, sister chromatids are exact copies of each other, containing identical DNA sequences. On the other hand, homologous chromosomes are pairs of chromosomes, with one inherited from each parent, and they can have different versions of genes due to genetic recombination during crossing over in prophase I. Choice A is incorrect because homologous chromosomes naturally have different centromeres. Choice C is incorrect as sister chromatids and homologous chromosomes do not exhibit repulsion or attraction during synapsis. Choice D is incorrect as sister chromatids separate during anaphase II, not anaphase I, while homologous chromosomes separate during anaphase I.

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