GED Science TestEarth and Space ScienceEasy

A team of researchers is studying a deep-sea ecosystem. They observe organisms that derive energy from chemical reactions rather than sunlight. This process is most likely:

  1. ACellular Respiration
  2. BPhotosynthesis
  3. CFermentation
  4. DChemosynthesis
Show answer & explanation

Correct answer: D. Chemosynthesis

Chemosynthesis is the process by which organisms produce organic compounds from inorganic chemicals, often in the absence of sunlight, making it common in deep-sea environments. Photosynthesis requires sunlight, and cellular respiration and fermentation are metabolic processes that break down organic compounds.

Why the other options are wrong

  • A. Cellular respiration is the process by which organisms combine oxygen with foodstuff molecules, diverting the chemical energy in these substances into life-sustaining activities and discarding waste products (carbon dioxide and water).
  • B. Photosynthesis is the process of converting light energy into chemical energy, which is not applicable in deep-sea environments without sunlight.
  • C. Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes, typically occurring in the absence of oxygen.

Chemosynthesis

The biological conversion of carbon molecules and nutrients into organic matter using the oxidation of inorganic molecules as an energy source, common in deep-sea environments.

  • Uses chemical energy, not light energy
  • Common in environments without sunlight (e.g., deep-sea vents)
  • Produces organic compounds

Memory trick: Light or Chemicals, life finds a way!

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