Which of the following is not one of the four nitrogenous bases that make up the DNA structure?

Correct Answer: C

Rationale: The correct answer is C: Uracil. Uracil is found in RNA, not DNA. The four nitrogenous bases in DNA are adenine, thymine, cytosine, and guanine. Choice A, Adenine, is a nitrogenous base in DNA. Choice B, Guanine, is another nitrogenous base in DNA. Choice D, Thymine, is also one of the four nitrogenous bases in DNA. Therefore, the correct answer is Uracil (Choice C).

Correct Answer: D

Rationale: The correct answer is D, Steroids. Steroids are a type of lipid that function as essential components of cell membranes and serve as precursors for significant hormones like estrogen and testosterone. Nucleic acids (choice A) are not lipids but are molecules like DNA and RNA that store genetic information. Proteins (choice B) and carbohydrates (choice C) are biomolecules but are not lipids and do not serve as precursors for hormones or membrane components.

Correct Answer: A

Rationale: The correct answer is A: Sugar and oxygen. During photosynthesis, plants convert carbon dioxide and water into glucose (sugar) and oxygen using sunlight. Choice B, 'Sugar and carbon dioxide,' is incorrect because carbon dioxide is one of the reactants, not a product. Choice C, 'Oxygen and nitrogen,' is incorrect as nitrogen is not a direct product of photosynthesis. Choice D, 'Nitrogen and carbon dioxide,' is incorrect because nitrogen is not a product of photosynthesis, and carbon dioxide is a reactant.

Correct Answer: A

Rationale: The correct answer is A: Proteins. Proteins are the most significant contributor to cellular function as they play crucial roles in almost all biological processes. They act as enzymes that catalyze reactions, are involved in cell signaling pathways, and provide structural support to cells. Phospholipids (Choice B), while important for cell membrane structure, do not have the same diverse functions as proteins in cellular processes. Carbohydrates (Choice C) primarily serve as an energy source and structural components but are not as versatile in cellular functions as proteins. Fatty acids (Choice D) are essential components of cell membranes and energy storage molecules but do not have the same broad range of functions as proteins in cellular processes.

Correct Answer: D

Rationale: In medical-surgical nursing, understanding the cellular components is crucial for comprehending physiological processes. The correct answer is D) Ribosomes. Ribosomes are the organelles responsible for protein synthesis and are abundant on the rough endoplasmic reticulum (ER). This arrangement allows newly synthesized proteins to be easily transported into the ER for modification and packaging. Option A) Microvilli are cellular membrane extensions found in the small intestine to increase surface area for absorption, not on the rough ER. Option B) Mitochondria are the powerhouses of the cell, generating ATP, and are not typically located on the rough ER. Option C) Lysosomes are organelles containing digestive enzymes for intracellular digestion and are not primarily associated with the rough ER. Educationally, this question reinforces the importance of understanding cell biology in the context of nursing practice. Knowing the functions and locations of cellular organelles like ribosomes on the rough ER can help nurses comprehend how protein synthesis occurs and how certain medications may impact cellular processes. This knowledge is fundamental for understanding diseases, drug actions, and patient care at a cellular level.