Nursing Elites

1. When a muscle shortens and generates force, this is called a:

• A. Contraction
• B. Relaxation
• C. Extension
• D. Atrophy

Correct answer: A

Rationale: When a muscle shortens and generates force, it is contracting. Contraction is the process by which muscle fibers develop tension and exert a pulling force on the bones they are attached to, resulting in movement. Relaxation refers to the phase when a muscle returns to its original length, allowing for rest or preparation for the next contraction. Extension, on the other hand, is the movement that increases the angle between body parts, moving them further apart. Atrophy is unrelated to muscle contraction and refers to the wasting away or decrease in size of muscle tissue due to disuse or disease. Therefore, the correct answer is 'Contraction.'

2. How does lymph move through the lymphatic vessels?

• A. By the pumping action of the heart
• B. Due to muscle contractions and breathing movements
• C. Through one-way valves within the vessels
• D. All of the above

Correct answer: C

Rationale: Lymph moves through the lymphatic vessels due to the presence of one-way valves within the vessels. These valves prevent the backflow of lymph and help propel the fluid forward as muscles contract and relax or due to breathing movements. Unlike blood circulation, the lymphatic system does not rely on the pumping action of the heart to move lymph. Choice A is incorrect because lymphatic circulation does not depend on the pumping action of the heart. Choice B is partly correct as muscle contractions and breathing movements do assist in propelling lymph, but the primary mechanism is the presence of one-way valves within the vessels, making choice C the most accurate answer. Choice D is incorrect as not all options listed contribute to how lymph moves through the lymphatic vessels.

3. What is the difference between a germline mutation and a somatic mutation?

• A. Germline mutations are passed to offspring, while somatic mutations are not.
• B. Germline mutations occur in reproductive cells, while somatic mutations occur in body cells.
• C. Germline mutations only affect genes, while somatic mutations can affect any DNA.
• D. Germline mutations are always beneficial, while somatic mutations are always harmful.

Correct answer: B

Rationale: Rationale: - Germline mutations are changes in the DNA of reproductive cells (sperm or egg cells) and can be passed on to offspring, affecting all cells in the resulting organism. - Somatic mutations are changes in the DNA of non-reproductive cells (body cells) and are not passed on to offspring. These mutations only affect the cells that arise from the mutated cell. - Option A is incorrect because somatic mutations are not passed to offspring. - Option C is incorrect because both germline and somatic mutations can affect any DNA. - Option D is incorrect because the effects of mutations, whether germline or somatic, can be beneficial, harmful, or have no significant impact.

4. Which part of the neuron receives signals from other neurons?

• A. Axon
• B. Dendrite
• C. Synapse
• D. Myelin sheath

Correct answer: B

Rationale: The correct answer is B, Dendrite. Dendrites are the part of the neuron that receive signals from other neurons and transmit them to the cell body. Axons transmit signals away from the cell body, synapse is the junction between neurons where neurotransmitters are released, and myelin sheath is a fatty layer that insulates and speeds up signal conduction along the axon. Therefore, choices A, C, and D are incorrect in the context of receiving signals from other neurons.

5. What is the importance of RNA splicing?

• A. Removes introns from the mRNA molecule
• B. Adds the poly-A tail to the mRNA molecule
• C. Activates the mRNA molecule for translation
• D. Modifies the structure of the protein

Correct answer: A

Rationale: RNA splicing is a crucial process in gene expression where non-coding regions called introns are removed from the pre-mRNA molecule, and the remaining coding regions called exons are joined together to form the mature mRNA molecule. This process ensures that only the protein-coding sequences are retained in the mRNA for translation, allowing for the production of functional proteins. Therefore, option A is the correct answer as it accurately describes the importance of RNA splicing in generating mature mRNA molecules for protein synthesis. B) Adding the poly-A tail to the mRNA molecule is a post-transcriptional modification that occurs after RNA splicing and is not directly related to the process of removing introns. C) Activating the mRNA molecule for translation is typically achieved through the addition of a 5' cap and the poly-A tail, rather than through RNA splicing. D) Modifying the structure of the protein is not directly related to the process of RNA splicing, which primarily focuses on mRNA maturation by removing non-coding introns.

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