Nursing Elites

1. What is the name of the regulatory region in a gene that controls its expression?

• A. Exon
• B. Intron
• C. Promoter
• D. Enhancer

Correct answer: C

Rationale: Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression. B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression. C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression. D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter. Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.

2. Which of the following best describes the function of the pericardium?

• A. It regulates blood flow through valves within the heart.
• B. It acts as a protective sac surrounding the heart.
• C. It generates the electrical impulses for heart contractions.
• D. It transmits electrical signals between the atria and ventricles.

Correct answer: B

Rationale: The correct answer is B: "It acts as a protective sac surrounding the heart." The pericardium is a double-layered membrane that surrounds and protects the heart, providing physical support and preventing overexpansion. It also helps reduce friction between the heart and surrounding structures during heartbeats. Options A, C, and D are incorrect as they describe functions of other parts of the heart such as valves, electrical impulse generation, and transmission pathways, respectively. Understanding the role of the pericardium in protecting the heart is crucial for comprehending the anatomical and physiological aspects of the cardiovascular system.

3. The main function of the nephrons is to:

• A. Store urine
• B. Filter blood and remove waste products
• C. Produce hormones
• D. Control blood pressure

Correct answer: B

Rationale: The correct answer is B: 'Filter blood and remove waste products.' Nephrons are the functional units of the kidneys responsible for filtering blood to remove waste products, excess ions, and water, while reabsorbing essential substances like glucose and amino acids. This process forms urine, which is stored in the bladder before being excreted. Options A, C, and D are incorrect because nephrons do not store urine, produce hormones, or directly control blood pressure; although the kidneys do play a role in long-term blood pressure regulation through mechanisms like the renin-angiotensin-aldosterone system.

4. 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: The correct answer is A: Schwann cells. Schwann cells are a type of glial cell in the peripheral nervous system that produce the myelin sheath around axons. Myelin sheath is essential for the rapid conduction of nerve impulses and provides insulation and protection to nerve fibers. Astrocytes are glial cells that provide support and maintain homeostasis in the central nervous system, but they do not produce myelin. Neurons are the main functional units of the nervous system responsible for transmitting nerve impulses. Oligodendrocytes are another type of glial cell in the central nervous system that produce myelin sheath around axons in that region, not in the peripheral nervous system where Schwann cells are responsible for myelination.

5. Which of the following is a characteristic of unsaturated fatty acids?

• A. They are solid at room temperature.
• B. They contain only single bonds.
• C. They have a higher melting point.
• D. They contain double or triple bonds.

Correct answer: D

Rationale: Unsaturated fatty acids contain double or triple bonds in their hydrocarbon chains. The other choices do not accurately describe unsaturated fatty acids.

6. The epiglottis is a small flap of cartilage located near the base of the tongue. What is its role during swallowing?

• A. Initiates the swallowing reflex
• B. Grinds food into smaller pieces
• C. Covers the trachea to prevent food aspiration
• D. Stores saliva for lubrication

Correct answer: C

Rationale: The epiglottis is a crucial anatomical structure that covers the trachea during swallowing to prevent food aspiration. When we swallow, the epiglottis folds over the trachea, directing food and liquids down the esophagus instead of entering the airway. This action helps to ensure that the food and liquids go to the stomach for digestion and not into the lungs, which can lead to aspiration pneumonia, a serious condition. Therefore, option C, 'Covers the trachea to prevent food aspiration,' is the correct role of the epiglottis during swallowing.

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