Nursing Elites

1. The dark, round structures observed within some bacterial cells are most likely:

• A. Ribosomes
• B. Flagella
• C. Endospores
• D. Capsules

Correct answer: C

Rationale: Endospores are the correct answer. Endospores are dark, round structures observed within some bacterial cells. They are highly resistant dormant structures formed by certain bacteria in response to harsh environmental conditions. Ribosomes are not dark, round structures within bacterial cells; they are responsible for protein synthesis. Flagella are long, whip-like appendages used for movement and are not dark, round structures within bacterial cells. Capsules are outer layers of polysaccharides that some bacteria produce for protection and adherence, not dark, round structures within bacterial cells.

2. An uncharged atom has an electron configuration of 1s2 2s2 2p6 3s2 and a mass number of 14. How many protons does it have?

• A. 14
• B. 6
• C. 8
• D. 12

Correct answer: B

Rationale: The correct answer is B (6 protons). The electron configuration provided corresponds to the element carbon, which has 6 protons. The mass number does not affect the number of protons in an atom, so despite the mass number of 14, the atom still contains 6 protons. Choice A (14) is incorrect because the mass number does not determine the number of protons. Choices C (8) and D (12) are incorrect as they do not match the number of protons in a carbon atom.

3. What type of bond connects sugar and phosphate in DNA?

• A. Hydrogen
• B. Ionic
• C. Covalent
• D. Overt

Correct answer: C

Rationale: The correct answer is Covalent (C). In DNA, a covalent bond connects sugar and phosphate molecules. This bond involves the sharing of electron pairs between the atoms, providing stability to the DNA structure. Hydrogen bonds are important in DNA structure but are not the primary bond connecting sugar and phosphate. Ionic bonds involve the transfer of electrons, and 'overt' is not a term related to the bond connecting sugar and phosphate in DNA.

4. Which cells myelinate neurons in the CNS?

• A. Schwann cells
• B. Astrocytes
• C. Microglia
• D. Oligodendrocytes

Correct answer: D

Rationale: The correct answer is D, Oligodendrocytes. Oligodendrocytes are responsible for myelinating neurons in the central nervous system (CNS). Schwann cells, found in the peripheral nervous system, are responsible for myelinating neurons there. Astrocytes support and maintain the neuronal environment, while microglia function as immune cells in the CNS, participating in immune responses and cellular debris clearance. Therefore, choices A, B, and C are incorrect for myelination of CNS neurons.

5. In an oxidation reaction,

• A. an oxidizing agent gains electrons.
• B. an oxidizing agent loses electrons.
• C. a reducing agent gains electrons.
• D. a reducing agent loses electrons.

Correct answer: B

Rationale: In an oxidation reaction, the substance being oxidized loses electrons, not gains them. An oxidizing agent is responsible for causing oxidation in another substance by accepting electrons, hence it undergoes reduction and loses electrons. Therefore, the correct statement is 'an oxidizing agent loses electrons,' making choice B the correct answer. Choices A, C, and D are incorrect because in an oxidation reaction, the oxidizing agent does not gain electrons, a reducing agent does not gain electrons, and a reducing agent does not lose electrons.

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