Nursing Elites

1. Calcitonin, a hormone that helps regulate calcium levels, is produced by the:

• A. Thyroid gland
• B. Parathyroid gland
• C. Thymus gland
• D. Adrenal gland

Correct answer: A

Rationale: Calcitonin is a hormone produced by the thyroid gland. It helps regulate calcium levels in the body by inhibiting the breakdown of bone and promoting calcium excretion by the kidneys. The parathyroid gland produces parathyroid hormone (PTH), which works in opposition to calcitonin to regulate calcium levels. The thymus gland is involved in the development of the immune system, and the adrenal gland produces hormones such as cortisol and adrenaline. Therefore, the correct answer is the thyroid gland as it specifically secretes calcitonin for calcium regulation.

2. What is the main function of valence electrons in chemical bonding?

• A. They are responsible for holding the nucleus together.
• B. They are involved in forming bonds with other atoms.
• C. They determine the element's physical properties.
• D. They play no role in chemical reactions.

Correct answer: B

Rationale: Valence electrons are the electrons in the outermost energy level of an atom. These electrons are involved in forming bonds with other atoms, which is crucial for chemical bonding. By participating in bonding, valence electrons determine an atom's ability to form compounds and engage in chemical reactions. Therefore, the primary function of valence electrons is to facilitate the formation of bonds between atoms, making option B the correct answer. Choices A, C, and D are incorrect because valence electrons primarily influence chemical bonding by participating in the formation of bonds between atoms, rather than holding the nucleus together, determining physical properties, or having no role in chemical reactions.

3. What are the components of an ECG?

• A. P wave, T wave, U wave
• B. P wave, QRS complex, T wave
• C. QRS complex, S wave, P wave
• D. T wave, S wave, U wave

Correct answer: B

Rationale: The correct answer is B: P wave, QRS complex, T wave. The components of an ECG include the P wave (atrial depolarization), QRS complex (ventricular depolarization), and T wave (ventricular repolarization). The P wave represents atrial depolarization, the QRS complex represents ventricular depolarization, and the T wave represents ventricular repolarization. Options A, C, and D have incorrect combinations of ECG components. Option A incorrectly includes the U wave, which is not a standard component of a typical ECG. Option C includes the S wave, which is not a primary component of a standard ECG. Option D includes the U wave, which is not a standard component, and the S wave, which is not a primary component of an ECG. Therefore, option B is the most accurate combination of components for an ECG.

4. Which orbital can hold a maximum of 8 electrons?

• A. s orbital
• B. p orbital
• C. d orbital
• D. f orbital

Correct answer: B

Rationale: The correct answer is the p orbital. Each p orbital can hold a maximum of 6 electrons (2 electrons in each of the 3 p orbitals), totaling 18 possible electrons when considering all three p orbitals. The s orbital can hold a maximum of 2 electrons, the d orbital can hold a maximum of 10 electrons, and the f orbital can hold a maximum of 14 electrons. Therefore, the p orbital is the orbital that can hold a maximum of 8 electrons, making it the correct choice.

5. Enzymes are ________ molecules that serve as _______ for certain biological reactions.

• A. Enzymes are irrelevant molecules that serve as suppressors for certain biological reactions.
• B. Enzymes are acidic molecules that serve as catalysts for certain biological reactions.
• C. Enzymes are lipid molecules that serve as catalysts for certain biological reactions.
• D. Enzymes are protein molecules that serve as catalysts for certain biological reactions.

Correct answer: D

Rationale: Enzymes are protein molecules that serve as catalysts for certain biological reactions. Enzymes are biological molecules that speed up chemical reactions in living organisms by lowering the activation energy required for the reactions to occur. They are typically proteins that have specific shapes and active sites that allow them to interact with specific substrates and facilitate reactions without being consumed themselves. The other choices are incorrect because enzymes are not irrelevant, acidic, or lipid molecules; they are primarily proteins known for their catalytic properties.

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