A pure culture of bacteria is made of…

• A. Around 1 million viable bacteria cells that are all of the same species.
• B. Around 1 million viable bacteria cells that are all descended from a single parent cell.
• C. Around 1 million viable bacteria cells that are a mixture of different bacterial species.
• D. Both A and B.
• E. Both A and C.
• F. Both B and C.

Answer: (D)

Verified step by step guidance

1. Understand the definition of a pure culture in microbiology: A pure culture consists of a population of cells that are all genetically identical and originate from a single parent cell.
2. Analyze option A: 'Around 1 million viable bacteria cells that are all of the same species.' This aligns with the definition of a pure culture, as all cells are of the same species.
3. Analyze option B: 'Around 1 million viable bacteria cells that are all descended from a single parent cell.' This also fits the definition of a pure culture, as all cells originate from a single parent cell.
4. Analyze option C: 'Around 1 million viable bacteria cells that are a mixture of different bacterial species.' This does not fit the definition of a pure culture, as it involves multiple species.
5. Combine the correct options based on the analysis: Since both A and B fit the definition of a pure culture, the correct answer is 'Both A and B.'