Questions 1. What are the signs of growth in a liquid medium? 2. Why is the mouth of a culture tube flamed after the cap is taken off and before the cap is put back on? 3. Why shouldn't test tube or petri dish lids be set onto the workbench? 4. Why is it important to maintain pure cultures? 5. What are all the different ways you've practiced aseptic technique in this lab? List as many as you can think of.

Question

UpStudy AI · Accepted Answer

1. **Signs of Growth in a Liquid Medium**  
   - An increase in cloudiness (turbidity) of the medium.  
   - Formation of sediment or a pellicle (a thin film) on the surface.  
   - Sometimes a change in pH or color if the medium has an indicator.

2. **Flaming the Mouth of a Culture Tube**  
   - When the cap is removed, there is a risk of airborne contaminants entering the tube.  
   - Flaming the tube’s mouth creates an upward convection current, which helps prevent microbes from settling into the tube.  
   - It also sterilizes the air immediately around the opening before the cap is replaced.

3. **Why Not to Set Lids on the Workbench**  
   - The workbench surface may be contaminated with dust or microbes, so placing lids directly on it can lead to contamination.  
   - This practice risks exposing sterile items to non-sterile surfaces, compromising the aseptic conditions.

4. **Importance of Maintaining Pure Cultures**  
   - Pure cultures ensure that you are studying a single organism without interference from contaminants.  
   - They provide reproducible and accurate experimental results because variables are limited to the chosen microorganism.  
   - Cross-contamination can lead to misinterpretation of data and flawed conclusions.

5. **Practices of Aseptic Technique in the Lab**  
   - Flaming the mouth of culture tubes before and after access.  
   - Sterilizing inoculating loops or needles before use (e.g., by flaming).  
   - Minimizing the time that culture vessels remain open.  
   - Avoiding contact of sterile items with non-sterile surfaces.  
   - Working near a flame or in a laminar flow hood to create a sterile field.  
   - Keeping lids and caps close to the tubes when not in use.  
   - Using proper hand hygiene and wearing gloves when necessary.  
   - Wiping down surfaces and instruments with disinfectants prior to beginning work.
1. **Signs of Growth in a Liquid Medium** - The medium becomes cloudy or forms a film on the surface. - There might be a change in color or pH. 2. **Flaming the Mouth of a Culture Tube** - To prevent contaminants from entering when the cap is removed. - Sterilizes the air around the tube opening. 3. **Why Not to Set Lids on the Workbench** - The workbench can be contaminated, leading to cross-contamination of sterile items. 4. **Importance of Maintaining Pure Cultures** - Ensures accurate and reproducible experimental results by studying a single organism. 5. **Practices of Aseptic Technique in the Lab** - Flaming tubes, sterilizing tools, minimizing tube exposure, keeping lids closed, using gloves, and maintaining a sterile environment.

Solución de inteligencia artificial de Upstudy

Responder

Solución

Beyond the Answer

preguntas relacionadas

Latest Biology Questions