What is the primary purpose of using an LB agar plate in microbiology laboratories?

• A. To provide nutrients and a solid surface for bacterial growth
• B. To detect the presence of viral particles in a sample
• C. To selectively inhibit the growth of Gram-positive bacteria
• D. To measure the oxygen consumption of microorganisms

Answer: (A)

Verified step by step guidance

1. Understand that LB agar plates are a common growth medium used in microbiology laboratories primarily for culturing bacteria.
2. Recognize that LB stands for Luria-Bertani, which is a nutrient-rich medium designed to support the growth of a wide variety of bacteria by providing essential nutrients such as peptides, vitamins, and minerals.
3. Note that the agar component solidifies the medium, creating a firm surface that allows individual bacterial colonies to grow and be easily observed and isolated.
4. Eliminate options that do not align with the function of LB agar plates: detecting viral particles, selective inhibition of Gram-positive bacteria, or measuring oxygen consumption are not primary purposes of LB agar.
5. Conclude that the primary purpose of using an LB agar plate is to provide both nutrients and a solid surface to support and observe bacterial growth.