Which best describes the purpose of using streak plates in microbiology laboratories?

• A. To isolate individual colonies from a mixed culture
• B. To determine the optimal growth temperature for bacteria
• C. To test the antibiotic sensitivity of microorganisms
• D. To measure the turbidity of a liquid culture

Answer: (A)

Verified step by step guidance

1. Understand that a streak plate is a microbiological technique used to separate individual bacterial cells on an agar surface.
2. Recognize that by spreading a mixed culture over the agar in a specific pattern, the bacterial cells become diluted across the plate.
3. As the cells are diluted, individual cells become isolated from each other, allowing them to grow into separate colonies.
4. Each isolated colony originates from a single bacterial cell, making it possible to obtain pure cultures for further study.
5. Therefore, the primary purpose of using streak plates is to isolate individual colonies from a mixed culture, which is essential for identifying and studying specific microorganisms.