Nursing Elites

1. Which structure of the nervous system carries an action potential in the direction of a synapse?

• A. Cell body
• B. Axon
• C. Neuron
• D. Myelin

Correct answer: B

Rationale: The correct answer is the axon. The axon is the elongated, threadlike part of a neuron that carries nerve impulses away from the cell body towards other neurons or target cells, such as muscles or glands, in the direction of a synapse. Action potentials travel along the axon as electrical signals to communicate with neighboring cells. The cell body (choice A) contains the nucleus and organelles but does not transmit action potentials. Neuron (choice C) is a broad term that includes the entire nerve cell, not a specific structure. Myelin (choice D) is a fatty substance that surrounds and insulates axons, aiding in the conduction of nerve impulses, but it does not directly carry the action potential towards a synapse.

2. Neurotransmitters send chemical messages across the gap between one neuron and another through which of the following structures?

• A. Schwann cell
• B. ganglion
• C. synapse
• D. axon

Correct answer: C

Rationale: Neurotransmitters send chemical messages across the gap between one neuron and another through a structure called the synapse. The synapse is a specialized junction where the axon of one neuron meets the dendrite or cell body of another neuron. Neurotransmitters are released from the axon terminal of the presynaptic neuron and travel across the synaptic cleft to bind to receptors on the postsynaptic neuron, transmitting the signal between the two neurons. Choice A, Schwann cell, is incorrect as Schwann cells are responsible for producing myelin sheath around axons in the peripheral nervous system, not for transmitting neurotransmitters between neurons. Choice B, ganglion, is incorrect as ganglia are clusters of nerve cell bodies outside the central nervous system and do not directly participate in the transmission of chemical messages between neurons. Choice D, axon, is incorrect as the axon is a long, slender projection of a neuron that conducts electrical impulses away from the cell body and towards the axon terminals, where neurotransmitters are released into the synapse, but it is not the structure across which neurotransmitters travel to communicate between neurons.

3. What type of bond connects sugar and phosphate in DNA?

• A. Hydrogen
• B. Ionic
• C. Covalent
• D. Overt

Correct answer: C

Rationale: The correct answer is Covalent (C). In DNA, a covalent bond connects sugar and phosphate molecules. This bond involves the sharing of electron pairs between the atoms, providing stability to the DNA structure. Hydrogen bonds are important in DNA structure but are not the primary bond connecting sugar and phosphate. Ionic bonds involve the transfer of electrons, and 'overt' is not a term related to the bond connecting sugar and phosphate in DNA.

4. Which structure in the lungs is the site of gas exchange?

• A. Trachea
• B. Alveoli
• C. Bronchioles
• D. Diaphragm

Correct answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from inhaled air diffuses into the bloodstream, while carbon dioxide from the blood is released into the alveoli to be exhaled. The trachea (Choice A) is the windpipe that carries air to and from the lungs, but it is not involved in gas exchange. Bronchioles (Choice C) are small air passages within the lungs that branch off from the bronchi, leading air to the alveoli but not directly involved in gas exchange. The diaphragm (Choice D) is a muscle below the lungs that helps in breathing by expanding and contracting the chest cavity, but it is not the site of gas exchange.

5. Which of the following is an example of an aromatic compound?

• A. Ethanol
• B. Toluene
• C. Acetone
• D. Butanal

Correct answer: B

Rationale: Toluene is an aromatic compound due to its benzene ring structure, which satisfies the criteria of aromaticity. Aromatic compounds contain conjugated pi electrons in a ring structure, providing extra stability. Ethanol, acetone, and butanal are not aromatic compounds as they do not possess a benzene ring or meet the aromaticity criteria. Ethanol is an alcohol, acetone is a ketone, and butanal is an aldehyde, none of which have the characteristic benzene ring structure of aromatic compounds.

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