Question

Your lab team mixes dry baker’s yeast with warm water and divides the mixture between two test tubes. You add 5 grams of sugar to one test tube but nothing to the other tube. A small balloon is placed over the mouth of each test tube. After 30 minutes your team records the following observations.

Yeast and warm water: The water is cloudy after a minute. After 30 minutes the yeast is settled to bottom of tube, water is less cloudy.

Yeast, warm water and sugar: The water is cloudy, a few bubbles have formed on top of the water. After 30 minutes the water is cloudy, lots of bubbles in the test tube, balloon has inflated some.

What is the BEST inference you could make about the yeast based on the data?
(4 Points)

The yeast needs warm water to grow.

The yeast bubbles when it contacts sugar.

Yeast is a living organism that uses sugar for energy.

Yeast is not a living organism because it did not change when added to water.

Answer 1

The yeasts are the eukaryotic, microscopic, unicellular organisms belonging to the kingdom fungi. Yeasts are widely used to prepare beer and wine. Yeasts break down the glucose and release ethanol and carbon dioxide. The best interference is yeasts bubbles when it contacts with sugar.

Step-by-step explanation:

Yeasts are organisms, which can respire aerobically or anaerobically. During the experiment, when yeasts are placed in a test tube with sugar, it starts to grow. The warm water in the test tube ensures the rapid growth of yeast. Sugar is the source of energy that is required by the yeasts to grow. Thus, during the multiplication of the yeast, they utilize oxygen and food to yield carbon dioxide. The gas is evolved and can be tested by the inflated balloon placed over the test tube. The yeasts bubbles out when it comes in contact with the sugar. Thus, to perform any experiment on living organisms, the population of those organisms should be in large quantity. this can be achieved by providing the sources of energy.