Question 1: What is the primary reason scientists developed the Three Domain System of classification?

Answer: To better categorize organisms based on genetic and cellular differences, especially at the molecular level.

Question 2: Define the three domains used in biological classification.

Answer: Bacteria, Archaea, and Eukarya.

Question 3: Which domain contains organisms that are more similar to eukaryotic cells in terms of genetic makeup?

Answer: Eukarya

Question 4: Fill in the blank: The domain ________ includes organisms that are often found in extreme environments and have unique cell membrane compositions.

Answer: Archaea

Question 5: Explain briefly how genetic analysis contributed to the development of the Three Domain System.

Answer: Genetic analysis, especially comparing ribosomal RNA sequences, revealed significant differences between organisms that led to the classification of two distinct prokaryotic domains (Bacteria and Archaea) and the eukaryotic domain (Eukarya).

Question 6: Why is genetic material considered more reliable than physical appearance when classifying organisms?

Answer: Because genetic material provides information about evolutionary relationships and cellular functions that may not be visible externally.

Question 7: Describe one difference between bacteria and archaea at the cellular level.

Answer: Archaea have cell membranes with different lipid compositions and distinct genetic sequences compared to bacteria.

Question 8: Which domain is most closely related to the evolution of eukaryotic cells?

Answer: Archaea

Question 9: Calculate the total number of domains if an organism belongs to the domain that includes multicellular plants and animals.

Answer: 1 (Eukarya)

Question 10: In your own words, explain why the Three Domain System replaced the older Five Kingdom classification.

Answer: The Three Domain System provides a more accurate reflection of evolutionary relationships based on genetic data, whereas the Five Kingdom system relied mainly on physical and metabolic traits, which could be misleading.