Cellular Respiration

Introduction:
Cellular respiration is the process by which the chemical energy in organic molecules like glucose is converted into ATP, the form of energy that is usable by organisms.
Everybody eats food to live and grow. The key word in understanding cellular respiration is “metabolism.” During cellular respiration, the cells in your body metabolize, or convert, the food you eat into energy. The chemical breakdown results in carbon dioxide, water and ATP. ATP powers cells, enabling processes requiring energy such as the transportation of molecules across cell membranes.

The chemical equation for the cellular respiration is shown below:
C6H12O6 + 6O2 (g) → 6 H2O + 6 CO2 (g) + ATP

Note that oxygen (O2) is a reactant; molecules of oxygen are required for the energy conversion reaction to proceed. Glucose may only be oxidized completely if sufficient oxygen is available.
Terrestrial animals (including humans) are constantly breathing in oxygen in order to convert glucose into ATP. This process is quite efficient at producing the required ATP for energy in a mammalian body. However, the complex chemical reactions involved in the conversion of glucose to ATP has a number of byproducts, including water and carbon dioxide (CO2). CO2 is considered a cellular waste product.
Regardless of our individual activity levels, we are always performing energy conversion reactions. Even we are resting, we are very busy at the cellular level. With increased physical activity, the demand for energy also increases, and there is a corresponding increase in the need for oxygen in order to breakdown more glucose for energy. This is why we breathe more heavily and at an increased rate when we are exercising. Increasing our intake of oxygen is only half of the equation; the other half involves exhaling cellular waste products, specifically carbon dioxide. As activity levels increase and more glucose is converted into ATP, more CO2 is produced as a byproduct.
Yeast is the quickest and most highly observable experiment type for the demonstration of cellular respiration.

Learning Objectives: Upon the successful completion of the activity- learners will be able to:
• State the formula for cellular respiration.
• List the difference between autotrophs and heterotrophs
• State the three stages of cellular respiration and where these stages occur
• Describe the effects of CO2 production and O2 delivery in the body
Purpose:
The purpose of this activity is to investigate how everyday nutrient metabolism influences the rate of cellular respiration.

Materials:
• A packet of active yeast- unicellular fungus that comes to life when warm water is added to it.
• Small amount of table sugar
• One Zip lock bag
• A cup of mildly warm water
Methods:
• Clear a small space.
• Open and place the empty zip lock bag in a container such as a plastic Tupperware
• Add one packet of active yeast to the Zip Lock bag. Now add one cup of water and 2 table spoon of sugar to the bag.
• Be sure to squeeze all the air out and seal the bag tight quickly.

Results:
• In your results section – be sure to provide the following.
• 2 images of your experiment (choose an image any time before the experiment and one image after the yeast and sugar reaction)
• What did you observe as a result of the reaction?

Discussion: In a paragraph please include the following in your discussion:

What reaction take place in the Zip Lock bag? What are the reactant and product of this reaction? What is the source of energy in this reaction? How does this reaction in the bag explain the metabolism of nutrients in your bodies? Please provide an explanation for each. What is the difference between autotroph and heterotroph? What category does the yeast come in? How does the amount of sugar, water and yeast and changing the water temperature will change the product of the reaction? What type of gas is released in the bag? When metabolizing your own sugars- how the process of Oxygen and Carbon di Oxide does gets done. Which cellular organelle is responsible for cellular respiration? List the three stages of cellular respiration and location these stages take place within this organelle.