Rucete ✏ Biology In a Nutshell
1. What Are Archaea?
- Archaea are a domain of single-celled microorganisms that are distinct from bacteria and eukaryotes.
- They have unique DNA sequences and are resistant to antibiotics like streptomycin and chloramphenicol.
- Archaea have different lipid compositions in their membranes and unique RNA polymerase and ribosomal proteins.
2. Types of Archaea
a) Methanogens
- Obligate anaerobes (cannot live in oxygen).
- Generate methane gas as a byproduct when converting H₂ and CO₂ into energy.
- Found in mud, swamps, and animal guts (like cows and termites).
b) Extremophiles
- Thrive in extreme environments.
i. Halophiles
- Live in environments with high salt concentrations (like salt lakes).
- Most are aerobic and heterotrophic, but some are anaerobic and photosynthetic using bacteriorhodopsin (a light-sensitive pigment).
ii. Thermophiles
- Live in hot environments (typically 60–80°C), such as hot springs or hydrothermal vents.
- Most are chemoautotrophs that use sulfur to produce energy.
iii. Other Extremophiles
- Can live in environments with high acidity (pH 1–4) or high basicity (pH 9–11).
- Also found in areas of high pressure such as deep-sea vents.
Tags:
Biology in a nutshell