Nursing Elites

1. How many moles of water are produced when 0.5 moles of methane (CH4) react with excess oxygen?

• A. 0.5 moles
• B. 1 mole
• C. 2 moles
• D. 3 moles

Correct answer: B

Rationale: The balanced chemical equation for the combustion of methane is: CH4 + 2O2 -> CO2 + 2H2O. This equation shows that 1 mole of methane produces 2 moles of water. Therefore, when 0.5 moles of methane react, they will produce 1 mole of water. The ratio of water to methane is 2:1, meaning that for every mole of methane that reacts, it produces 2 moles of water. Since only 0.5 moles of methane are reacting, the amount of water produced will be half of what would be produced if 1 mole of methane reacted, resulting in 1 mole of water being produced. Choice A is incorrect because it does not consider the stoichiometry of the reaction. Choices C and D are incorrect as they do not align with the balanced chemical equation and the stoichiometric ratios involved in the reaction.

2. Which property of a wave is responsible for determining its energy?

• A. Amplitude
• B. Wavelength
• C. Frequency
• D. Velocity

Correct answer: C

Rationale: The correct answer is C, Frequency. The energy of a wave is determined by its frequency, not its amplitude, wavelength, or velocity. According to the equation E = h*f, where E is energy, h is Planck's constant, and f is frequency, the energy of a wave is directly proportional to its frequency. Higher frequency waves carry more energy, while lower frequency waves carry less energy. Therefore, frequency plays a crucial role in determining the energy content of a wave, making it the correct choice in this context.

3. What is the primary function of tight junctions, specialized regions between animal cells?

• A. Communication between cells
• B. Anchorage between cells
• C. Selective passage of materials
• D. All of the above

Correct answer: C

Rationale: The correct answer is C: Selective passage of materials. Tight junctions act as specialized structures between animal cells that create a barrier to the passage of materials. Their primary function is to prevent the leakage of extracellular fluid and control the selective passage of molecules between cells. This selective control is crucial in regulating the movement of substances across cell layers. Tight junctions do not directly facilitate communication between cells or provide anchorage between cells, as their main role is to regulate the passage of materials. Choices A and B are incorrect as tight junctions do not primarily serve for communication or anchorage between cells.

4. Where does the digestion of food start?

• A. Esophagus
• B. Stomach
• C. Small intestine
• D. Mouth

Correct answer: D

Rationale: The correct answer is the mouth. Digestion begins in the mouth where mechanical breakdown occurs through chewing, and chemical breakdown begins with saliva. Enzymes in saliva start breaking down carbohydrates, initiating the digestion process. The esophagus is responsible for transporting food from the mouth to the stomach and does not play a role in the digestion process. The stomach continues the digestion process after the food leaves the mouth. The small intestine is primarily responsible for absorbing nutrients from the digested food, rather than being the initial site of digestion.

5. What is the ultimate end product of glucose breakdown in glycolysis?

• A. ATP
• B. NADPH
• C. Pyruvic acid
• D. Oxygen

Correct answer: C

Rationale: The ultimate end product of glucose breakdown in glycolysis is pyruvic acid. During glycolysis, glucose is broken down into pyruvic acid through a series of enzymatic reactions. ATP is produced as an energy carrier during glycolysis, but it is not the final end product. NADPH is not a direct product of glycolysis; it is mainly produced in the pentose phosphate pathway. Oxygen is not a product of glycolysis but is used as an electron acceptor in the electron transport chain of cellular respiration.

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