Question 1: Archaea are a domain of single-celled organisms that are distinct from bacteria and eukaryotes. They often live in extreme environments and have unique biochemical features. Explain why Archaea are considered a separate domain of life.

Answer: Because they have distinct genetic, biochemical, and structural characteristics that differentiate them from bacteria and eukaryotes, including unique membrane lipids and genetic sequences.

Question 2: Which of the following environments are most commonly associated with Archaea? A) Freshwater lakes B) Hot springs C) Human skin D) Arctic ice

Answer: B) Hot springs

Question 1: Describe two key biochemical differences between Archaea and bacteria.

Answer: Archaea have ether-linked lipids in their cell membranes and possess unique enzymes and metabolic pathways not found in bacteria.

Question 2: The genetic material of Archaea is most similar to that of which other domain? A) Bacteria B) Eukaryotes C) Viruses D) Plants

Answer: B) Eukaryotes

Question 1: Scientific studies have shown that certain Archaea species thrive in environments with high sulphur concentrations. In a sample from a deep-sea hydrothermal vent, researchers found that 70% of the microbial population were Archaea. Explain what this suggests about the ecological role of Archaea in such environments.

Answer: It suggests that Archaea play a vital role in these extreme environments, likely contributing to sulphur cycling through their metabolic processes, and are well-adapted to survive and possibly dominate in high-sulphur conditions.

Question 2: A sample contains 10^6 cells of Archaea and 10^5 cells of bacteria. If the total biomass of Archaea is 2 grams, estimate the biomass of bacteria assuming the biomass per cell is equal for both groups.

Answer: Bacteria biomass = (Number of bacteria / Number of Archaea) × Archaea biomass = (10^5 / 10^6) × 2g = 0.2g

Question 1: Design a simple experiment to test the effect of temperature on the growth rate of Archaea. Include variables, controls, and safety precautions.

Answer: The experiment should include temperature as the independent variable (e.g., 20°C, 40°C, 60°C), with the growth rate (measured by cell count or optical density) as the dependent variable. Controls would include cultures kept at optimal temperature and sterilised conditions to prevent contamination. Safety precautions include wearing protective equipment, handling extreme temperatures carefully, and sterilising all materials to avoid contamination.

Question 1: Explain how enzymes derived from Archaea are utilised in industrial processes, especially those requiring high temperatures or extreme conditions.

Answer: Archaeal enzymes are thermostable and active under extreme conditions, making them ideal for industrial processes such as PCR amplification, biofuel production, and waste treatment where high temperatures or harsh chemicals are involved.

Question 2: Identify one potential benefit and one challenge of using Archaea in biotechnology.

Answer: Benefit: They produce enzymes that function in extreme conditions, improving industrial efficiency. Challenge: Culturing Archaea can be difficult and costly due to their specialised environmental requirements.