Yeast Lab


Caracas, January 23rd, 2014
Biology

Juice as a food source for yeast instead of glucose for the fermentation used to produce CO2



INTRODUCTION

Chemical reaction
C6H12O6  2 CH3CH2OH + 2 CO2 + energy

Background
Yeast is an ovoid fungus and a eukaryotic organism; yeast cells are living and natural. They seek for air to be able to reproduce, but the absence of air, sugaris formed into alcohol. Relating to why we use vegetable oil to avoid that the O2 enters and forms aerobic energy instead of anaerobic energy that is the type of energy needed to form fermentation. It happens naturally when bread is made, the sugar provided by flour is renovated into alcohol, which is evaporated during baking and CO2, proving fermentation. In backing bread this makes the dough riseand an amount of energy that is stable to keep it alive.
Bakers on bread factories are supposed to know the percentage of yeast used on the formula depending on the type of bread is going to be baked. For example, to form a german brown bread, which is dense and heavy, less yeast and CO2 is needed whereas to bake hamburger bread more amounts of yeast and CO2 is needed so that the dough islighter. Nutritionists; wine, rum and beer maker are also studying yeast and what it can make. Scientists know how it works but they are so eager to know every part of it that every time they test different things so that it can be discovered to its full. Cellular respiration is very important to living organisms because it provides energy to the organisms. Allowing living organism to perform allnecessary functions to be able to live. Expecting that with the results of my lab I can answer my big question, “how do variables affect cellular respiration?” To be concise and clear, I decided to state all kinds of variables. Dependent variable being CO2 pressure measured one kPa every half a minute, independent variable was using fruit juice instead of using glucose that was what everybody used andsome controlled variables.

Research Question
What effect does the use of fruit juice instead of glucose have on the amount of gas released from the fermentation on yeast, measured from gas pressure?


Hypothesis
If glucose is used instead of fruit juice as a food source then a more stable measurement of pressure of the CO2 will be recorded.

Independent Variable
Fruit juiceinstead of glucose

Dependent Variable
CO2 pressure and the measuring units is one kPa every half minute

Dependent Variable Explanation
The gas pressure sensor measures how much pressure and how much energy it is released by measuring one kPa every half a minute. Using this sensor it can be answered the big question of the lab, which is “how do variables affect cellular respiration”
Themeasuring of a kPa every half a minute will allow me to know to how the pressure is changing. Carbon dioxide is a waste product of fermentation and it is the gas that is measured in this lab, more carbon dioxide means more cellular respiration and less carbon dioxide means less cellular respiration.


MATERIALS:












Fruit Juice
Incubator
Chemistry stand
Utility clampLab coat


METHOD
PRELIMINARY Activity for Sugar Fermentation by Yeast from Vernier Software & Technology

Controlled Variables
To be able to make or try to make experiments with the same variables we used the controlled variables. As the word says it those are the variables that make every attempt with the same conditions excluding your independent variable. Some of these variableswhere the amount of yeast and glucose/fruit juice, which was 2 ml in each attempt, the water temperature was also controlled and had to be at 40 degrees Celsius. Oil concentration is other of my controlled variables and it is very important because it prevents O2 from entering the mixtures, which makes cellular respiration an example of anaerobic respiration. The yeast is incubated because the...