# Explain how hydrothermal vents are considered a possible environment for the origin of life on Earth.

> IB DP Biology Higher Level (2023 syllabus) — A2.1 Origins of cells · Explain · 4 marks

> Deep-sea hydrothermal vents release mineral-rich superheated water into the surrounding ocean. Scientists have proposed that alkaline hydrothermal vents, in particular, may have provided conditions suitable for the emergence of the first living cells.

## Mark scheme (4 marks)

1. Hydrothermal vents provide a chemical energy gradient (proton/ion gradient) that could drive early metabolism without sunlight.
2. Mineral pores/chambers in vent chimneys could act as compartments, concentrating organic molecules and functioning analogously to a primitive cell membrane.
3. Vents supply reduced molecules (e.g. hydrogen, hydrogen sulfide, methane) that could serve as reactants for the abiotic synthesis of organic monomers.
4. The hydrothermal vent environment is shielded from harmful UV radiation, and conditions are relatively stable, making sustained prebiotic chemistry more plausible.

## Key terms

- [hydrothermal vent](https://www.gradenine.co.uk/glossary/hydrothermal-vent)

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