Which Form of Sulfur Can Algae and Plants Use but Not

Question

Which form of sulfur can algae and plants use but not produce?
A) hydrogen sulfide (H₂S)
B) elemental sulfur (S⁰)
C) sulfuric acid (H₂SO₄)
D) sulfate (SO₄²⁻ )
E) both elemental sulfur and hydrogen sulfide

Accepted Answer

Algae and plants can only use sulfate (SO4²⁻) as a form of sulfur for making amino acids, proteins, and other biomolecules. They are not capable of producing sulfate, but they are able to take up sulfate ions from the environment and use them for growth and metabolism. Hydrogen sulfide and elemental sulfur are reduced forms of sulfur that can be used by certain bacteria, but not algae and plants. Sulfuric acid is a highly reactive and corrosive compound that is not commonly found in the environment as a source of sulfur for organisms.