Nursing Elites

1. Which of the following enzymes is responsible for adding a nucleotide to a growing DNA chain?

• A. Helicase
• B. Ligase
• C. Nuclease
• D. Polymerase

Correct answer: D

Rationale: The correct answer is Polymerase. Polymerase is the enzyme responsible for adding nucleotides to a growing DNA chain during DNA replication. Helicase unwinds the DNA double helix to separate the DNA strands for replication, Ligase joins DNA fragments together by catalyzing the formation of phosphodiester bonds between them, and Nuclease cuts or degrades DNA strands. Therefore, choices A, B, and C are incorrect in the context of adding nucleotides to a growing DNA chain.

2. What makes bone resistant to shattering?

• A. The calcium salts deposited in the bone
• B. The collagen fibers
• C. The bone marrow and network of blood vessels
• D. The intricate balance of minerals and collagen fibers

Correct answer: D

Rationale: Bone is resistant to shattering due to the intricate balance of minerals and collagen fibers. The minerals provide strength to the bone, while the collagen fibers offer flexibility. This combination ensures that bone is a robust and resilient tissue. Choice A (The calcium salts deposited in the bone) is incorrect as calcium salts alone do not provide the necessary flexibility for bone to withstand shattering. Choice B (The collagen fibers) is partially correct as collagen fibers contribute to the flexibility of bone but alone are not sufficient for resistance to shattering. Choice C (The bone marrow and network of blood vessels) is incorrect as they do not directly contribute to the physical resistance of bone to shattering.

3. What type of lens is thinner at the center than at the edges and causes light rays to diverge?

• A. Convex lens
• B. Concave lens
• C. Diverging lens
• D. Plano-convex lens

Correct answer: B

Rationale: A concave lens is thinner at the center than at the edges, causing light rays to diverge when passing through it. This type of lens is also known as a diverging lens because it causes light rays to spread out. Concave lenses are used in various optical devices to correct vision problems and in scientific instruments to diverge light rays for specific purposes. The other choices are incorrect. A convex lens is thicker at the center and converges light rays, while a plano-convex lens has one flat surface and one convex surface, converging light. Diverging lens is a general term that can refer to concave or plano-concave lenses, but in this context, the specific type being referred to is a concave lens.

4. A patient's body is not properly filtering blood. Which of the following body parts is most likely malfunctioning?

• A. Medulla
• B. Heart
• C. Nephrons
• D. Renal cortex

Correct answer: C

Rationale: Nephrons are the functional units of the kidneys responsible for filtering blood and removing waste products to form urine. If a patient's body is not properly filtering blood, it is most likely due to dysfunction or impairment in the nephrons of the kidneys. The heart is responsible for pumping blood, not filtering it, making choice B incorrect. The medulla and renal cortex are specific parts of the kidney but do not directly perform the filtration function carried out by the nephrons, making choices A and D incorrect.

5. In the context of optical fibers, chromatic dispersion refers to:

• A. The total internal reflection of light
• B. The spreading of light pulses due to different colors traveling at slightly different speeds
• C. The bending of light at the fiber core-cladding interface
• D. The absorption of light by the fiber material

Correct answer: B

Rationale: Chromatic dispersion in optical fibers refers to the spreading of light pulses due to different colors (wavelengths) traveling at slightly different speeds. This phenomenon can cause the different components of a light pulse to arrive at the receiver at slightly different times, leading to signal distortion. Choice A is incorrect because total internal reflection refers to the phenomenon where light is reflected back into the medium it originated from when hitting the boundary at an angle greater than the critical angle. Choice C is incorrect as it describes the principle of light being guided within an optical fiber through total internal reflection at the core-cladding interface. Choice D is incorrect as the absorption of light by the fiber material does not relate to chromatic dispersion.

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