Nursing Elites

1. The chemical equation below is unbalanced. When it is properly balanced, how many molecules of carbon dioxide (CO2) are produced for each molecule of propane (C3H8) in the reaction? 3C3H8 + 5O2 → 3CO2 + 4H2O

• A. One Half.
• B. Two.
• C. Three.
• D. Five.

Correct answer: B

Rationale: The balanced chemical equation for the combustion of propane is: 3C3H8 + 5O2 → 3CO2 + 4H2O. This equation shows that for every 3 molecules of propane (C3H8) consumed, 3 molecules of carbon dioxide (CO2) are produced. Therefore, when properly balanced, 3CO2 are produced for each molecule of propane used. Thus, the correct answer is B: Two. Choices A, C, and D are incorrect because they do not reflect the correct stoichiometry as determined by the balanced equation.

2. What is the fatty substance that coats axons to insulate, protect, and speed up impulses?

• A. Myelin
• B. Dendrite
• C. Neuron
• D. Synapse

Correct answer: A

Rationale: The correct answer is 'Myelin.' Myelin is a fatty substance that functions as an insulator for axons, providing protection and enhancing the speed of electrical impulses along neurons. This insulation is essential for ensuring efficient and rapid communication within the nervous system. Choices B, C, and D are incorrect. Dendrites are branched extensions of a neuron that receive signals, neurons are the basic building blocks of the nervous system that transmit information, and synapses are the junctions between neurons where communication occurs.

3. Which of the following structures plays a crucial role in controlling the cell cycle and preventing uncontrolled cell growth?

• A. The centrioles
• B. The nucleolus
• C. The Golgi apparatus
• D. The endoplasmic reticulum

Correct answer: A

Rationale: The correct answer is A: The centrioles. Centrioles are cylindrical structures found in animal cells that are crucial in organizing the spindle fibers during cell division (mitosis). They play a vital role in separating chromosomes during cell division, ensuring each daughter cell receives the correct number of chromosomes. Additionally, centrioles are involved in the formation of cilia and flagella, essential for cell motility and sensory functions. The nucleolus is responsible for ribosome production, the Golgi apparatus processes and packages proteins, and the endoplasmic reticulum is involved in protein synthesis and lipid metabolism. These structures do not have a direct role in controlling the cell cycle and preventing uncontrolled cell growth.

4. Which muscle has involuntary cells that are branched and striated and connected by intercalated discs with gap junctions?

• A. Smooth muscle
• B. Cardiac muscle
• C. Skeletal muscle
• D. Epithelial muscle

Correct answer: B

Rationale: The correct answer is B: Cardiac muscle. Cardiac muscle cells fit the description provided in the question; they are involuntary, striated, and branched, with intercalated discs containing gap junctions that allow for synchronized contractions of the heart. Smooth muscle (choice A) lacks striations and is found in the walls of internal organs. Skeletal muscle (choice C) is voluntary and attaches to bones for movement. 'Epithelial muscle' (choice D) is not a valid muscle type, making it an incorrect choice.

5. The liver plays a vital role in digestion. What is one of the main functions of the liver in the digestive system?

• A. Physical breakdown of food
• B. Production of digestive enzymes
• C. Storage and processing of nutrients
• D. Elimination of waste products

Correct answer: C

Rationale: The correct answer is C: Storage and processing of nutrients. The liver plays a crucial role in processing nutrients absorbed from the small intestine, storing glycogen, vitamins, and minerals, and regulating blood sugar levels by releasing or storing glucose as needed. Choices A, B, and D are incorrect because the physical breakdown of food primarily occurs in the mouth and stomach, the production of digestive enzymes is mainly carried out by the pancreas and small intestine, and the elimination of waste products is primarily managed by the large intestine and kidneys, not the liver.

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