Nursing Elites

1. Which of the following is an example of a chemical property of matter?

• A. Boiling point
• B. Flammability
• C. Density
• D. Conductivity

Correct answer: B

Rationale: Flammability is an example of a chemical property of matter because it describes how a substance reacts with oxygen in the air to produce heat and light. Chemical properties involve the ability of a substance to undergo a chemical change or reaction, such as burning. Boiling point, density, and conductivity are examples of physical properties, not chemical properties. Boiling point is the temperature at which a substance changes from a liquid to a gas, density is the mass of a substance per unit volume, and conductivity is the ability to conduct electricity. Therefore, flammability best exemplifies a chemical property as it pertains to the substance's reaction with oxygen, while the other options are physical properties that describe characteristics without changing the substance's chemical composition.

2. What term refers to the point of contact between a motor neuron and a muscle fiber, where communication occurs to initiate muscle contraction?

• A. Sarcomere
• B. Synapse
• C. Tendon
• D. Myofibril

Correct answer: B

Rationale: The correct answer is B, 'Synapse.' The synapse is the specific term that refers to the point of contact between a motor neuron and a muscle fiber, where communication occurs to initiate muscle contraction. At the synapse, neurotransmitters are released by the motor neuron, triggering the muscle fiber to contract. Choice A, 'Sarcomere,' is incorrect as a sarcomere is the basic unit of muscle contraction, not the point of contact between a motor neuron and a muscle fiber. Choice C, 'Tendon,' is incorrect as tendons are fibrous connective tissues that connect muscle to bone, not involved in neuronal communication. Choice D, 'Myofibril,' is incorrect as a myofibril is a structure within muscle fibers where muscle contractions occur, not the specific point of contact for communication between a motor neuron and a muscle fiber.

3. Long bones are one of the five major types of bones in the human body. Which of the following bones are long bones?

• A. Sacrum
• B. Clavicle
• C. Patella
• D. Ulna, Fibula, Humerus

Correct answer: D

Rationale: Long bones are characterized by their elongated shape and include bones like the ulna, fibula, and humerus. These bones are crucial for providing support, structure, and facilitating movement in the human body. The sacrum, clavicle, and patella are not classified as long bones. The sacrum is a triangular bone at the base of the spine, the clavicle is a collarbone, and the patella is the kneecap. While these bones have important functions, they do not fit the definition of long bones due to their shape and structure.

4. What is the role of RNA interference in silencing genes?

• A. Increases protein production
• B. Promotes gene mutation
• C. Inhibits the expression of specific genes
• D. Repairs damaged DNA

Correct answer: C

Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.

5. Which type of reaction undergoes hydrolysis?

• A. Anabolism
• B. Catabolism
• C. Exothermic
• D. Endothermic

Correct answer: B

Rationale: The correct answer is 'Catabolism.' Catabolic reactions involve the breakdown of larger molecules into smaller ones, often through hydrolysis, where water is added to break chemical bonds. This process is essential for the degradation of complex molecules and the release of energy stored in chemical bonds. Choice A, 'Anabolism,' is incorrect as anabolism involves the synthesis of complex molecules from simpler ones. Choices C and D, 'Exothermic' and 'Endothermic,' refer to the heat energy exchange during a reaction and are not directly related to the process of hydrolysis.

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