Nursing Elites

1. Which statement accurately describes the periodic trends in atomic radius?

• A. Increases down a group and decreases across a period
• B. Decreases down a group and increases across a period
• C. Remains constant throughout the table
• D. Fluctuates unpredictably based on individual elements

Correct answer: A

Rationale: The correct statement is that atomic radius increases down a group and decreases across a period. When moving down a group, additional electron shells increase the distance from the nucleus, leading to larger atomic radii. On the other hand, when moving across a period, the number of electron shells remains constant, but the increasing nuclear charge pulls electrons closer, resulting in smaller radii. Choice B is incorrect because atomic radius does not decrease down a group and increase across a period. Choice C is incorrect because atomic radius does not remain constant; it exhibits specific trends. Choice D is incorrect because atomic radius follows predictable trends based on the periodic table structure, rather than fluctuating unpredictably.

2. When a biologist describes the physical and visible expression of a genetic trait, which of the following is being referred to?

• A. Phenotype
• B. Allele
• C. Gamete
• D. Genotype

Correct answer: A

Rationale: The correct answer is A: Phenotype. Phenotype specifically refers to the observable physical characteristics resulting from the interaction of an individual's genetic makeup (genotype) with environmental influences. It represents the outward expression of an organism's genetic makeup. Allele, represented by choice B, refers to different forms of a gene and is not the visible expression of a trait. Gamete, represented by choice C, is a reproductive cell and not directly related to the physical expression of traits. Genotype, represented by choice D, refers to the genetic makeup of an organism and is distinct from the observable physical characteristics denoted by phenotype.

3. Myelin sheath is a fatty substance that insulates and protects the long extensions of some nerve cells. It is produced by:

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

Correct answer: A

Rationale: Schwann cells are indeed responsible for producing the myelin sheath in the peripheral nervous system. These cells wrap around axons to form the myelin sheath, which enhances the speed of nerve impulse conduction. In the central nervous system, oligodendrocytes are responsible for producing the myelin sheath. Astrocytes provide support and maintenance functions for neurons, while neurons are the nerve cells themselves and do not produce myelin. Therefore, the correct answer is Schwann cells as they are specifically involved in myelin production in the peripheral nervous system.

4. What happens during expiration?

• A. The diaphragm contracts and the thoracic cavity expands.
• B. The diaphragm relaxes and the thoracic cavity contracts.
• C. The thoracic cavity expands, increasing pressure.
• D. The diaphragm relaxes and moves upward.

Correct answer: B

Rationale: The correct answer is B. During expiration, the diaphragm relaxes, causing the thoracic cavity to contract. As the thoracic cavity decreases in size, the pressure inside the lungs increases, leading to air flowing out of the lungs. This process helps to expel carbon dioxide-rich air from the body. Choices A, C, and D are incorrect. In choice A, the diaphragm contracting and the thoracic cavity expanding describes inspiration, not expiration. Choice C is incorrect because during expiration, the thoracic cavity actually decreases in size. Choice D is incorrect as the diaphragm moving upward is not a typical movement associated with expiration.

5. Which of the following is NOT a type of vaccine?

• A. Live attenuated vaccine
• B. Toxoid vaccine
• C. Conjugate vaccine
• D. Antibiotic

Correct answer: D

Rationale: A) Live attenuated vaccine: This type of vaccine contains a weakened form of the virus or bacteria that causes the disease. When administered, it stimulates an immune response without causing the disease itself. B) Toxoid vaccine: Toxoid vaccines are made from toxins produced by bacteria that have been inactivated. They stimulate the immune system to produce antibodies against the toxin, providing immunity against the disease. C) Conjugate vaccine: Conjugate vaccines are made by combining a weak antigen with a strong antigen to enhance the immune response. They are commonly used to protect against bacterial infections. D) Antibiotic: Antibiotics are medications used to treat bacterial infections by killing or inhibiting the growth of bacteria. They are not a type of vaccine but rather a class of antimicrobial drugs. Therefore, the correct answer is D) Antibiotic, as it is not a type of vaccine.

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