Lab Report 5: Metabolism Experiment 1 – Fermentation by Yeast (31 points)© 2013 eScience Labs, LLC. All rights reserved.        Instructions: Enter yo

Lab Report 5: Metabolism

 

Experiment 1 – Fermentation by Yeast (31 points)

© 2013 eScience Labs, LLC. All rights reserved. 

 

      Instructions: Enter your experimental data into Table 1 below. Take a picture of your experiment after your last measurement and include your photograph in your lab report below. 

 

Table 1: Yeast Fermentation Data
 Tube Initial Gas Height (mm)  Final Gas Height (mm)  Net Change 
1      
2      
3      
4      
5      

 

 

Attach Image 1: Labeled Fermentation by Yeast Test Tubes 

 

 

Instructions: Answer the following questions in complete sentences using correct grammar, spelling, and terminology.

  1. Did you notice a difference in the rate of respiration between the various sugars? Did the artificial sugar provide a good starting material for fermentation? 

 

-Yes there is a change in the rate of respiration of various sugars. Natural sugars respire faster than artificial sugar.

 

  1. How do you know that anaerobic fermentation was occurring? 

-Anaerobic respiration can be identified by the breakdown of glucose into ethyl alcohol, carbon dioxide, and energy.

 

  1. Hypothesize why some of the sugar or sweetener solutions were not metabolized, while others were. Research the chemical formula of Equal® and Splenda® and explain how it would affect yeast respiration. 

Because of their complex structure few sugars were metabolized faster whereas there the others were not. Sugar molecules with smaller structures like glucose, and fructose can be metabolized easily whereas complex sugar molecules like sucrose, and fructose cannot be metabolized easily.

 

  1. If you observed respiration, identify the gas that was produced. Suggest two methods you could use for positively identifying this gas. 

-Carbon dioxide gas was produced. CO2 produced can be identified by  Durham’s tube and inverted test tube technique.

 

  1. How do the results of this experiment relate to the role yeast plays in baking? 

-The CO2 gas produced by yeast fermentation plays a  role in the baking industry.

 

  1. What would you expect to see if the yeast cell metabolism slowed down? How could this be done? 

-Slow metabolism in the yeast can be identified by the yeast’s less alcohol and gas production. This slow metabolism may be due to the temperature and lack of sugar sources.

 

  1. Indicate sources of error and suggest an improvement (for example, what types of controls could be added?). 

– There are several things that can help speed up the growth of yeast. One is to make sure that the yeast is fresh and active. Another is to provide the yeast with a warm, moist environment. Sugar can also help yeast to grow more quickly.

 

 

 

 

 

 

 

 

Experiment 2: Aerobic Respiration in Beans (69 points)

© 2013 eScience Labs, LLC. All rights reserved. 

 

      Instructions: Enter your experimental data into Tables 2 and 3 below. Take a picture of your experiment after your last measurement and include your photograph in your lab report below. 

 

Table 2: Bromothymol Blue Color Change Over Time for Pinto Bean Trial
 Time Pre-Soaked Pinto Beans  Dry Pinto Beans  No Pinto Beans 
0 min GREEN  GREEN GREEN
30 min GREEN GREEN GREEN
60 min HALF GREEN GREEN GREEN
90 min MOSTLY CLEAR GREEN GREEN GREEN
120 min CLEAR GREEN  GREEN GREEN
150 min YELLOW GREEN GREEN
180 min YELLOW GREEN GREEN
24 hours DEEP YELLOW ORANGE LIGHT GREEN GREEN

 

 

Table 3: Bromothymol Blue Color Change Over Time for Kidney Bean Trial
 Time Pre-Soaked Kidney Beans  Dry Kidney Beans  No Kidney Beans 
0 min      
30 min      
60 min      
90 min      
120 min      
150 min      
180 min      
24 hours      

 

 

Attach Image 2: Aerobic Respiration in Beans Experiment 

 

 

Instructions: Answer the following questions in complete sentences using correct grammar, spelling, and terminology.

  1. What evidence do you have to prove that cellular respiration occurred in the beans? Explain your answer. 

 

  1. How did the color of the bromothymol blue solution in each beaker change over time in each condition? 

 

  1. What can be inferred from the color change of the bromothymol blue solution? 

 

  1. What is the mechanism driving the bromothymol blue solution color change? 

 

  1. Were there differences in the rates of respiration in the pinto beans vs. the kidney beans? How did you come to this conclusion? 

 

  1. If this experiment were conducted at 0 °C, what difference would you see in the rate of respiration? Why? 

 

7. Would you expect to find CO2 in your breath? Why? 

 

  1. What are the controls in this experiment, and what variables do they eliminate? Why is it important to have a control for this experiment? 

 

9. What else could you incorporate into this experiment to verify that the gas is responsible for the color change? Design an experiment that shows the steps required. 

 

 

Lab Report 4: Electrolytes, Water, Acids, and Bases Lab 15: Experiment 1 – Breathing and Acid-Base Balance (50 points)© 2013 eScience Labs, LLC. All r

Lab Report 4: Electrolytes, Water, Acids, and Bases

 

Lab 15: Experiment 1 – Breathing and Acid-Base Balance (50 points)

© 2013 eScience Labs, LLC. All rights reserved. 

Instructions: Enter your experimental data into Table 1 below and answer the question. Take a picture of your experiment after your last measurement and include your photograph in your lab report.

Table 1: Color Change of Sodium Bicarbonate Solution With and Without the Addition of CO2
Beaker Starting Color Final Color Time to Change to Final Color
1      
2      

 

1. Was the time required to change the solution different for the two beakers? Why or why not? 

Attach Image 1: Breathing and Acid-Base Balance Experiment 

 

Lab 15: Experiment 2 – Urine pH (50 points)

© 2013 eScience Labs, LLC. All rights reserved. 

Instructions: Answer the questions below and take a picture of your experiment after your last measurement and include your photograph in your lab report.

1. What was the pH of the urine? Is this normal?

2.  Describe two factors that can affect urine pH. 

Attach Image 2: Urine pH Experiment