Question 1: Describe the main purpose of the Three Domain System in biological classification.

Answer: The main purpose of the Three Domain System is to categorize all living organisms into three broad groups—Bacteria, Archaea, and Eukarya—based on genetic and molecular differences.

Question 2: Explain how the genetic differences among the three domains are used to classify microorganisms.

Answer: Genetic differences are identified by analyzing DNA sequences, such as rRNA gene sequences, which reveal evolutionary relationships and distinguish bacteria, archaea, and eukaryotes.

Question 1: Define the term 'microorganism' and give an example of each of the three domains.

Answer: A microorganism is a tiny organism not visible to the naked eye; examples include bacteria (e.g., Escherichia coli), archaea (e.g., Halobacterium), and eukaryotes (e.g., yeast).

Question 2: Why is genetic analysis more reliable than cellular structure alone for classifying organisms in the Three Domain System?

Answer: Genetic analysis provides precise information about evolutionary relationships and molecular differences, which are more consistent and universal than cellular structures that can vary among organisms.

Question 1: If a DNA sequence of 1,500 base pairs from two microorganisms differs by 15 base pairs, what is the percentage difference? Use the formula: (Number of differing base pairs / Total base pairs) x 100%.

Answer: 1% (Since (15 / 1500) x 100% = 1%)

Question 1: Design a simple experiment to test whether a newly discovered microorganism belongs to the Bacteria or Archaea domain. Include variables, controls, and safety precautions.

Answer: The experiment involves isolating the microorganism and analyzing its DNA for specific genetic markers characteristic of Bacteria or Archaea. Variables include environmental conditions and DNA extraction methods. Controls should include known Bacteria and Archaea samples. Safety precautions involve sterile techniques and using biosafety cabinets to prevent contamination and exposure.

Question 1: A sample of microorganisms shows that 85% of its DNA sequences are similar to those of known Archaea, while only 10% are similar to Bacteria, and the rest are eukaryotic. What does this data suggest about the classification of this microorganism?

Answer: The data suggest that the microorganism is most likely an Archaea, as its DNA sequences are predominantly similar to those of known Archaea, indicating its classification within that domain.

Question 1: Explain how the discovery of extremophiles has influenced our understanding of the Three Domain System. (6 marks)

Answer: The discovery of extremophiles—organisms that live in extreme environments—has expanded our understanding of microbial diversity and provided evidence that archaea are distinct from bacteria. This led to the establishment of the Three Domain System, recognizing archaea as a separate domain based on genetic and metabolic differences, thus shaping modern taxonomy.

Question 1: Describe how understanding the genetic makeup of microorganisms from different domains can aid in developing nanotechnology-based medical treatments.

Answer: By analyzing the genetic information of microorganisms from different domains, scientists can identify unique biomolecules and enzymes that can be used to design nanomaterials or nanodevices for targeted drug delivery, diagnostics, and antimicrobial therapies.

Question 2: In what ways can nanotechnology assist in the classification and study of microorganisms within the Three Domain System?

Answer: Nanotechnology can enable precise genetic analysis, high-resolution imaging, and manipulation of microorganisms at the molecular level, enhancing classification accuracy and enabling detailed study of microbial structures and functions across the three domains.