Nursing Elites

1. An object is moving in a circle at constant speed. Is there a net force acting on it?

• A. Yes, always
• B. No, never
• C. Only if its speed is changing
• D. Only if its direction is changing

Correct answer: D

Rationale: When an object is moving in a circle at a constant speed, there is a net force acting on it. This net force is directed towards the center of the circle and is responsible for continuously changing the direction of the object's velocity, even though the speed remains constant. Therefore, the correct answer is D because the net force is required to change the direction of the object's motion in a circular path. Choices A, B, and C are incorrect because the presence of a net force is necessary to continuously change the object's direction as it moves in a circular path, irrespective of changes in speed.

2. What determines the defining characteristic of an element?

• A. Neutrons in its nucleus
• B. Electrons surrounding the nucleus
• C. Protons in its nucleus
• D. All of the above

Correct answer: C

Rationale: The defining characteristic of an element is determined by the number of protons in its nucleus, which is referred to as the atomic number. The number of protons uniquely identifies an element. The correct answer is choice C because the number of protons in the nucleus of an atom defines its elemental identity, as different elements have a unique number of protons. Neutrons and electrons do play essential roles in the atom, but they do not determine the defining characteristic of an element. Neutrons contribute to the stability of the nucleus and isotopes of an element, while electrons are involved in chemical bonding and the reactivity of an atom.

3. Which of the following distinguishes the isotopes of an element?

• A. Isotopes are atoms of the same element that have different ionic charges.
• B. Isotopes are atoms of elements within the same group on the periodic table.
• C. Isotopes are atoms of the same element that have different numbers of neutrons.
• D. Isotopes are atoms of the same element with different electron configurations.

Correct answer: C

Rationale: Isotopes are defined as atoms of the same element that have the same number of protons in their nucleus but different numbers of neutrons. This leads to variations in atomic mass for isotopes of an element. The different number of neutrons in isotopes results in differences in their atomic mass and properties while still belonging to the same element. Choice A is incorrect because isotopes do not have different ionic charges, they have the same chemical properties. Choice B is incorrect because isotopes are not atoms of elements within the same group on the periodic table; they are variants of the same element. Choice D is incorrect because isotopes of an element have the same electron configuration, differing only in the number of neutrons in the nucleus.

4. What describes a cell’s reaction to being placed in a hypertonic solution?

• A. The cell will shrink as water is pulled out of the cell to equalize the concentrations inside and outside of the cell.
• B. The cell will swell as water is pulled into the cell to equalize the concentrations inside and outside of the cell.
• C. The cell will remain the same size since the concentrations inside and outside the cell are equal to begin with.
• D. The pH inside the cell will drop in order to equalize the pH inside and outside the cell.

Correct answer: A

Rationale: A cell placed in a hypertonic solution has a higher solute concentration outside the cell compared to inside. This creates a concentration gradient that causes water to move out of the cell through osmosis to equalize the concentrations on both sides. As a result, the cell will shrink or undergo plasmolysis, as water is pulled out of the cell. Choice B is incorrect because a hypertonic solution causes water to move out of the cell, leading to shrinkage rather than swelling. Choice C is incorrect as a hypertonic solution results in a concentration gradient that leads to water leaving the cell, causing it to shrink. Choice D is incorrect because pH is not directly affected by being placed in a hypertonic solution; the change in solute concentration primarily impacts water movement.

5. What is the end product of glycolysis?

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

Correct answer: D

Rationale: The correct answer is D: Pyruvic acid. The end product of glycolysis is pyruvic acid, not lactic acid, ATP, or NADPH. Pyruvic acid is a key intermediary in cellular respiration and can be further metabolized to produce energy through processes like the citric acid cycle and oxidative phosphorylation. Lactic acid is produced in the absence of oxygen during fermentation, ATP is a product of cellular respiration but not the direct end product of glycolysis, and NADPH is generated in other metabolic pathways such as the pentose phosphate pathway, not in glycolysis.

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