Nursing Elites

1. Which of the following is unique to covalent bonds?

• A. Most covalent bonds are formed between the elements H, F, N, and O.
• B. Covalent bonds are dependent on forming dipoles.
• C. Bonding electrons are shared between two or more atoms.
• D. Molecules with covalent bonds tend to have a crystalline solid structure.

Correct answer: C

Rationale: The correct answer is C: 'Bonding electrons are shared between two or more atoms.' This statement is unique to covalent bonds. In covalent bonds, atoms share electrons to achieve a stable electron configuration, which leads to the formation of a bond. This sharing of electrons is a fundamental characteristic of covalent bonds and distinguishes them from other types of chemical bonds, such as ionic bonds, where electrons are transferred rather than shared. Choices A, B, and D do not represent unique characteristics of covalent bonds. Choice A describes some common elements involved in covalent bonds, choice B refers to the concept of dipoles, which can also exist in other types of bonds, and choice D describes a property of molecules (crystalline solid structure) that is not exclusive to covalent bonds.

2. Which structure do cells rely on for movement?

• A. Flagellum
• B. Microtubule
• C. Pili
• D. Vesicle

Correct answer: A

Rationale: The correct answer is A: Flagellum. Cells rely on flagella for movement, which are whip-like structures that propel the cell forward through their whipping motion. Flagella provide motility to single-celled organisms and certain cells in multicellular organisms. Microtubules, on the other hand, provide structural support to the cell and play a role in intracellular transport. Pili are short, hair-like structures used for attachment to surfaces or other cells, not for movement. Vesicles are membrane-bound sacs involved in intracellular transport, aiding in the movement of substances within the cell, but not in the movement of the cell itself.

3. Following successful heart transplant surgery, the patient's body will need to take medications to:

• A. Suppress the immune system and prevent rejection of the new heart.
• B. Reduce overall blood pressure.
• C. Dissolve any remaining blood clots.
• D. Stimulate the growth of new heart tissue.

Correct answer: A

Rationale: After heart transplant surgery, the patient's body will need to take medications to suppress the immune system and prevent rejection of the new heart. This is essential to ensure that the body does not identify the transplanted heart as a foreign entity and mount an immune response against it, which could lead to transplant rejection and failure. Choices B, C, and D are incorrect because post-heart transplant medications primarily focus on preventing rejection by suppressing the immune system, rather than reducing blood pressure, dissolving blood clots, or stimulating the growth of new heart tissue.

4. Which of the following is NOT a tissue layer found in skeletal bone?

• A. periosteum
• B. bone marrow
• C. enamel
• D. cancellous bone

Correct answer: C

Rationale: Enamel is a hard, outer layer that covers the crown of a tooth and is not a tissue layer found in skeletal bone. The other options, periosteum, bone marrow, and cancellous bone, are all tissue layers or components found in skeletal bone. Periosteum is the connective tissue layer covering the bone surface, bone marrow is found within the bone cavities, and cancellous bone is a spongy, porous bone tissue.

5. Which vitamin requires intrinsic factor for proper absorption?

• A. Vitamin A
• B. Vitamin C
• C. Vitamin D
• D. Vitamin B12

Correct answer: D

Rationale: Vitamin B12 requires intrinsic factor, a glycoprotein secreted by the parietal cells of the stomach, for proper absorption in the small intestine. Intrinsic factor binds to vitamin B12 and facilitates its absorption in the ileum. Deficiency in intrinsic factor can lead to pernicious anemia, a condition characterized by a lack of vitamin B12 absorption. Options A, B, and C are incorrect. Vitamin A is absorbed in the small intestine with the help of bile salts; Vitamin C is absorbed in the small intestine via active transport; Vitamin D is absorbed in the small intestine through a process involving bile salts and micelles. It is essential for students to understand this relationship as it highlights the importance of intrinsic factor in the absorption of specific vitamins and the consequences of its deficiency.

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