Anaerobic Respiration Lab



Name: _________________________________________________ Block: ______ Date: ________

Cellular Respiration in Yeast

PURPOSE: To observe anaerobic respiration performed by yeast by measuring the amount of gas produced using a balloon.

MATERIALS:

|125 mL Erlenmeyer flask |1 latex balloon |

|50 mL yeast suspension |1 piece of string |

|30 mL sugar solution |1 metric ruler |

SETUP: Sugar solution and yeast suspension will be mixed together in an Erlenmeyer flask. A balloon will be put on top of the flask. The set up will be observed for an hour. What do you think will happen and why?

NULL HYPOTHESIS: ___________________________________________________________

HYPOTHESIS: ___________________________________________________________

PROCEDURE:

1. Blow up the balloon and let out the air in order to stretch it out.

2. Place 50 ml of the yeast suspension into the flask.

3. Add 30 ml of sugar solution to the yeast suspension in the flask.

4. Swirl the flask until the syrup is completely dissolved in the yeast suspension.

5. Cover the flask tightly with the balloon.

6. Observe and record qualitative observations every 10 minutes.

7. Measure and record the circumference in cm with the string every 10 minutes.

DATA: Make quantitative observations every 10 minutes. Record your data on the table below and analyze your data in a graph on the graph provided.

Table 1: The rate of anaerobic respiration (cm/min) in yeast exposed to sugar versus water.

| |Trial 1 |Trial 2 |Control |

|Time (min) |(With Sugar) (cm) |(With Sugar) (cm) |(No Sugar) |

| | | |(cm) |

|0 | | | |

|10 | | | |

|20 | | | |

|30 | | | |

|40 | | | |

|50 | | | |

|60 | | | |

Graph 1: Give a title to the graph explaining what it is showing.

Title: _______________________________________________________________

| |

Analysis Questions:

1. Why was measuring the circumference of the balloon a measure of the rate of anaerobic respiration?

2. What kind of anaerobic fermentation was the yeast performing? Explain why.

3. Discuss the process of glycolysis and anaerobic fermentation. Why did you have to add syrup or sugar solution to the suspension for glycolysis to begin?

4. After completing this experiment what are additional research questions that could be tested?

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