Which of the following do prokaryotic cells lack?

Correct Answer: D

Rationale: The correct answer is D: Prokaryotic cells lack membrane-bound organelles, such as mitochondria or a nucleus, distinguishing them from eukaryotic cells. Prokaryotic cells do have genetic material, a cell membrane, and cytoplasm. Choice A is incorrect because prokaryotic cells do have a cell membrane, which is essential for maintaining cell structure and regulating what enters and exits the cell. Choice B is incorrect because prokaryotic cells contain genetic material, typically in the form of a single circular chromosome. Choice C is incorrect because prokaryotic cells have cytoplasm, where various cellular activities take place.

Correct Answer: A

Rationale: The correct answer is A: To produce amino acids. During the translation stage of protein synthesis, the mRNA is decoded to assemble a specific sequence of amino acids. These amino acids then fold into a functional protein. Choices B, C, and D are incorrect because the translation stage specifically deals with the production of amino acids, not nucleotides, fatty acids, or nucleic acids.

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.