Lab Protocol - Fermentation in Yeast (Unit 9 Respiration)

Summary

This video script details the step-by-step process of conducting a fermentation experiment, beginning with the accurate measurement and preparation of yeast and solution in a beaker. The mixture is incubated for five minutes before being transferred into fermentation tubes. These tubes are then placed in an incubator and monitored for carbon dioxide production at 10-minute intervals. The results show varying levels of fermentation between two samples, influenced by the amount of sugar available to the yeast, ultimately highlighting the role of sugar in yeast fermentation efficiency.

Takeaways

• 🔬 Accurate measurement of yeast is essential for the experiment, done using a digital balance.
• 🧪 The yeast is mixed with a solution in a beaker to prepare for the fermentation process.
• ⏱ The mixture is incubated at room temperature for five minutes before transferring to fermentation tubes.
• 📏 A small amount of the solution is added first to the fermentation tube to remove air bubbles, ensuring accurate readings.
• 🔄 The remaining solution is then added to complete the transfer into the fermentation tube.
• 🧑‍🔬 The fermentation tubes are placed in an incubator to undergo a 40-minute incubation period.
• ⏲ The fermentation process is monitored at 10-minute intervals to observe carbon dioxide production.
• 🔍 Observations reveal that at the midpoint, one sample (tube on the left) had less fermentation activity than the other (tube on the right).
• 📊 At the end of the experiment, it was clear that one tube showed substantial fermentation, while the other did not.
• 💡 The difference in fermentation levels was attributed to the amount of sugar available to the yeast in each tube.

Q & A

What is the first step in the fermentation process?

The first step in the fermentation process is measuring the appropriate amount of yeast using a digital balance.

Why is the yeast transferred to a beaker after being measured?

The yeast is transferred to a beaker so that it can be mixed with the appropriate solution before being added to the fermentation tube.

How is the yeast and solution mixture prepared before incubation?

The yeast and solution are mixed using a glass stir rod in the beaker, and the mixture is allowed to incubate at room temperature for five minutes.

What is done to the fermentation tube before adding the solution?

A small amount of the solution is first added to the fermentation tube, and the tube is tilted to remove any air bubbles in the top portion.

Why is it important to remove air bubbles from the fermentation tube?

Removing air bubbles is crucial because they can interfere with accurate measurement of the carbon dioxide produced during fermentation.

What happens after the air bubbles are removed from the fermentation tube?

Once the air bubbles are removed, the remaining solution from the beaker is added to the fermentation tube.

How long are the fermentation tubes incubated, and how often are they checked?

The fermentation tubes are incubated for a total of 40 minutes, with checks made at 10-minute intervals to observe the progress of fermentation.

What observations were made midway through the experiment?

Midway through the experiment, it was observed that both samples were undergoing fermentation, but the tube on the left showed less carbon dioxide production compared to the tube on the right.

What conclusion was drawn from the final observations of the experiment?

At the end of the experiment, it was concluded that one of the fermentation tubes performed significantly more fermentation than the other, which was due to the amount of sugar available to the yeast.

What does the difference in fermentation activity between the two tubes suggest?

The difference in fermentation activity suggests that the availability of sugar plays a critical role in the amount of fermentation that occurs, with more sugar leading to more fermentation and carbon dioxide production.