OSMT (Ontario Society of Medical Technologists) Practice Exam

What are the basic ingredients of all media?

1. Vitamins, blood, antibiotics

2. Agar, distilled water, electrolytes

3. Eggs, pH indicators, gelling properties

4. Tap water, seaweed, dissolved oxygen

The correct answer is: Agar, distilled water, electrolytes

The basic ingredients of all media are agar, distilled water, and electrolytes. Agar serves as a solidifying agent that provides a stable environment for the growth of microorganisms. Distilled water ensures the purity of the media, avoiding contamination that could affect growth results. Electrolytes are crucial as they provide essential ions necessary for various physiological processes of the microorganisms, helping maintain osmotic balance and supporting biochemical reactions. While other choices include components that might be found in specific types of media, they do not define the basic composition required for creating a growth medium suitable for a wide range of organisms. For instance, vitamins and blood are important in enriched media but are not universally necessary for all media types. Similarly, eggs, pH indicators, and gelling properties are more specialized components. Lastly, while tap water, seaweed, and dissolved oxygen may be relevant in certain contexts, they do not represent the foundational elements that all media must include.