Practice Questions

Correct: The formation of nucleotides from inorganic substances further supports the hypothesis that life's building blocks formed before living cells existed. A: Not experimentally testable. C: Biogenesis concerns existing life producing life. D: Cell theory does not explain the origin of life. Concept: Experimental evidence supporting chemical evolution.**

Correct: Membrane-bound organization allows efficient biochemical reactions and greater stability. B: Chloroplasts evolved much later. C, D: Far more advanced features. Concept: Functional significance of protocells.

Correct: Biological evolution began once the first living, self-replicating cells appeared. B, C, D: These events occurred much later. Concept: Chemical versus biological evolution.

Correct: The experiment provided strong support for chemical evolution. A: Spontaneous generation has been disproved. C: No living cells were produced. D: Evolution continues. Concept: Scientific significance of Miller-Urey experiment.

Correct: A less reducing atmosphere is less favorable for organic synthesis. A: Opposite of expected result. B: Gas composition affects outcomes. D: Proteins are not formed directly. Concept: Experimental reasoning.

Correct: Organic molecules aggregated into membrane-bound structures before true cells evolved. A, C, D: These occurred much later in evolution. Concept: Sequence of origin of life.

Correct: Oxygen inhibits the accumulation of organic compounds by oxidizing them. A: Oxidation is unfavorable. B: Atmosphere strongly influences reactions. D: Proteins cannot form directly from inorganic substances. Concept: Application of chemical evolution.

Correct: The earliest organisms were anaerobic heterotrophs because oxygen was absent. A: Requires oxygen. B: Photosynthesis evolved later. D: Atmospheric oxygen was unavailable. Concept: Earliest metabolism.

Correct: Oxygen oxidizes newly formed organic molecules, preventing their accumulation. B, C, D: These factors do not prevent organic synthesis to the same extent. Concept: Primitive versus modern Earth.

Correct: Lipids can self-assemble into membrane-bound vesicles, an important step in protocell formation. A: Genetic information is stored by nucleic acids. C: Lipids are not enzymes. D: DNA replication requires proteins and nucleic acids. Concept: Protocell formation.