Nursing Elites

1. Which of the following is directly transcribed from DNA and represents the first step in protein synthesis?

• A. siRNA
• B. rRNA
• C. mRNA
• D. tRNA

Correct answer: C

Rationale: mRNA (messenger RNA) is directly transcribed from DNA in the nucleus during the process of transcription. It serves as a template for protein synthesis during translation in the cytoplasm. mRNA carries genetic information from the DNA to the ribosomes, where it determines the sequence of amino acids in a protein. Thus, mRNA represents the first step in protein synthesis as it carries the code from the DNA to be translated into a protein. Choice A, siRNA (small interfering RNA), is involved in post-transcriptional gene silencing and does not play a role in protein synthesis. Choice B, rRNA (ribosomal RNA), is a component of the ribosome and plays a structural and functional role in protein synthesis but is not directly transcribed from DNA. Choice D, tRNA (transfer RNA), is responsible for bringing amino acids to the ribosome during protein synthesis but is not directly transcribed from DNA.

2. What term describes a series of muscle contractions that transports food down the digestive tract in a wave-like fashion?

• A. digestion
• B. deglutition
• C. defecation
• D. peristalsis

Correct answer: D

Rationale: Peristalsis is the correct term for the series of muscle contractions that move food down the digestive tract in a wave-like manner. This process helps propel food through the esophagus, stomach, and intestines, facilitating digestion and nutrient absorption. Digestion (Choice A) refers to the breakdown of food into smaller components, deglutition (Choice B) is the act of swallowing, and defecation (Choice C) is the elimination of waste from the body. Therefore, peristalsis is the most appropriate term to describe the described muscle contractions in the digestive system.

3. Which epithelial tissue type is the outermost layer of your skin an example of?

• A. Simple cuboidal
• B. Stratified squamous
• C. Simple columnar
• D. Stratified columnar

Correct answer: B

Rationale: The outermost layer of the skin, known as the epidermis, is composed of stratified squamous epithelial tissue. This type of tissue is well-suited for protection against mechanical stress and dehydration, making it ideal for the skin's barrier function. Simple cuboidal (Choice A) epithelial tissue is found in areas where secretion and absorption occur, such as kidney tubules. Simple columnar (Choice C) epithelial tissue lines the digestive tract, providing a large surface area for absorption. Stratified columnar (Choice D) epithelial tissue is less common and is found in limited regions like parts of the male urethra and ducts of some glands, but not in the outermost layer of the skin.

4. What do lacteals absorb in the small intestine?

• A. Carbohydrates
• B. Lipids
• C. Proteins
• D. Nonpolar nutrients

Correct answer: B

Rationale: Lacteals are lymphatic capillaries in the small intestine that specialize in absorbing dietary lipids. These lipids are then transported into the lymphatic system for further processing and distribution throughout the body. Choice A (Carbohydrates) is incorrect because carbohydrates are primarily digested and absorbed in the small intestine by enzymes and transported to the liver. Choice C (Proteins) is incorrect because proteins are broken down into amino acids and absorbed in the small intestine, mainly by the villi. Choice D (Nonpolar nutrients) is incorrect as it is a vague term and not specific to what lacteals absorb, which are primarily lipids.

5. What are the two primary functions of the respiratory system?

• A. Delivering nutrients and removing CO2
• B. Delivering O2 and removing CO2, maintaining blood pH
• C. Maintaining blood pH and delivering nutrients
• D. Delivering O2 and nutrients to the cells

Correct answer: B

Rationale: The correct answer is B. The respiratory system's primary functions include delivering oxygen (O2) to the body's cells for cellular respiration and removing carbon dioxide (CO2), thereby aiding in the maintenance of blood pH. These functions are crucial for gas exchange and the overall metabolic processes within the body. Choice A is incorrect as the respiratory system primarily delivers O2, not nutrients, and removes CO2, not delivering it. Choice C is incorrect as while the respiratory system helps maintain blood pH by removing CO2, it does not primarily deliver nutrients. Choice D is incorrect as it combines the functions of delivering O2 and nutrients, which are distinct roles of different systems in the body.

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