Question 1: Archaea are a group of microorganisms distinct from bacteria and eukaryotes. Describe two unique features that differentiate Archaea from bacteria.

Answer: Archaea have different cell membrane lipids and genetic sequences compared to bacteria.

Question 1: Define 'extremophile' and explain why many Archaea are classified as extremophiles.

Answer: An extremophile is an organism that thrives in extreme environmental conditions; many Archaea are extremophiles because they live in environments like hot springs or deep-sea vents.

Question 2: Explain how the genetic material of Archaea differs from that of bacteria.

Answer: Archaea have histone proteins associated with their DNA and possess some genes similar to eukaryotes, unlike bacteria.

Question 1: If an Archaea population in a hot spring doubles every 4 hours, how many Archaea will be present after 24 hours if the initial population is 1,000?

Answer: 16000

Question 2: Calculate the growth rate (per hour) of an Archaea population that increases from 500 to 4000 in 8 hours.

Answer: Growth rate ≈ 25.99% per hour

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

Answer: The experiment involves culturing Archaea in controlled environments with varying temperatures. Independent variable: temperature; dependent variable: growth rate; control variables: nutrient levels, pH, and incubation time. Safety precautions include handling hot equipment carefully, using protective gear, and working in sterile conditions to prevent contamination.

Question 1: A study reports that Archaea found in deep-sea vents have a population density of 2×10^6 cells per cubic centimetre. If a sample volume is 10 cubic centimetres, estimate the total number of Archaea in the sample and discuss the significance of their high density.

Answer: Total Archaea = 2×10^6 cells/cm³ × 10 cm³ = 2×10^7 cells. The high density indicates these Archaea are well adapted to extreme environments and play a crucial role in deep-sea ecosystems, such as in nutrient cycling.

Question 1: Describe one way in which Archaea are utilised in biotechnology or industry, and explain the benefit of using Archaea in this context.

Answer: Archaea are used in bioremediation to clean up oil spills because they can survive in harsh conditions and break down pollutants efficiently, offering an eco-friendly solution.