Question 1: Define bacteria and explain their significance in biological systems.

Answer: Bacteria are microscopic single-celled organisms that can be found in nearly all environments. They are significant because some cause disease, while others are used in biotechnology and nutrient cycling.

Question 2: Describe one way in which bacteria could potentially pose a risk to astronauts during space missions.

Answer: Bacteria can multiply in the closed environment of a spacecraft, potentially causing infections or contaminating equipment, which could endanger astronaut health.

Question 3: In the context of space exploration, why is it important to control bacterial growth onboard spacecraft?

Answer: Controlling bacterial growth is important to prevent infections, contamination of scientific experiments, and to maintain a safe environment for astronauts.

Question 4: What mechanisms do bacteria use to survive in harsh environments such as space?

Answer: Bacteria can form spores, have resistant cell walls, and possess DNA repair mechanisms to survive extreme conditions like vacuum, radiation, and extreme temperatures.

Question 5: Calculate the number of bacteria present after 24 hours if a single bacterium divides every 20 minutes. (Use the formula: N = N₀ × 2^(t / d), where N₀ = initial number, t = time in minutes, d = doubling time).

Answer: N = 1 × 2^(144 / 20) = 1 × 2^7.2 ≈ 1 × 149.0 ≈ 149 bacteria

Question 6: Identify three variables that would affect the growth rate of bacteria in a spacecraft environment.

Answer: Temperature, nutrient availability, and humidity levels.

Question 7: Propose one safety measure to reduce bacterial contamination during long-term space missions.

Answer: Implementing sterilisation protocols and using antimicrobial surfaces within the spacecraft.

Question 8: Explain why bacterial spores are a concern for space missions.

Answer: Bacterial spores are resistant to extreme conditions such as radiation, heat, and vacuum, making them difficult to eradicate. Their presence could lead to contamination of equipment and pose health risks to astronauts if they germinate under favourable conditions.

Question 9: Discuss how bacteria could be harnessed for beneficial purposes in space exploration technology.

Answer: Bacteria can be used in bioremediation to recycle waste and break down pollutants, produce oxygen through biological processes, and synthesize medicines or nutrients needed for long-duration missions. Their adaptability makes them valuable for maintaining life support systems in space.

Question 10: Describe a hypothetical experiment to test the effectiveness of a new sterilisation method for bacteria in space conditions.

Answer: Design an experiment where bacterial cultures are exposed to the sterilisation method in a controlled environment simulating space conditions (vacuum, radiation, temperature). After treatment, samples would be incubated to assess bacterial survival. Control samples without sterilisation would be used for comparison. Variables include sterilisation duration and intensity. Safety precautions should include containment and proper disposal of biohazards.