Brandon1

The Effect Temperature has on Yeast
Respiration:
What Temperature is the Most Suitable For Yeast Respiration?

Samaya Brandon
AP Biology
McCandless
12 February 2015

Brandon2

Samaya Brandon
AP Biolog
McCandless
12 February 2015
The Effect Temperature Has on Yeast Respiration
Research Question
: Throughout the course of this experiment the question “What effects does temperature of water have on the process of yeast respiration,” is being asked. Background Information
: Yeast is a microorganism that can respirate or fermentate based on its surrounding environment. When oxygen is present yeast undergoes aerobic respiration and without oxygen is a process called anaerobic respiration. In both processes glucose is used up and as a results end up forming ethanol and carbon dioxide

C 6 H 12 O6 → 2 C 2 H 6 OH + 2 CO2 Glucose Ethanol Carbon Dioxide This is the chemical reaction of fermentation, which produces ethanol and carbon dioxide as metabolic waste products.
Cellular respiration is a process essential to all living things.
Energy is made from glucose in respiration, ATP is the most basic form of energy in respiration. Respiration can occur anaerobically or aerobically.
When yeast is mixed with water and sugar carbon dioxide form in the representation of foam. The optimal temperature for cellular respiration in yeast can be

Brandon3

determined by the amount of carbon dioxide created. Environments that are too cold or hot or has too little of sugar can cause a slow in respiration rates or even death in the cells.
Hypothesis

: H eating a substance results in more movements of particles and more collision in the atoms. Colliding of particles causes bonds to break easier and new ones are created.Heat is one of the factors that are known to speed up the process of an reaction.. Therefore it is assumed that the higher the temperature is in the solution the more CO2 will be produced. In this experiment the various temperature listed above will be added into a mixture of 15g of yeast and
20g of sugar, the amount of foam created ( as a production of carbon dioxide) will determine which is the optimal temperature for yeast respiration. Variables
:
a. Independent Variables: a control temperature of 20°C and then 30°C, 40°C, 50°C and
60°C.
b. Dependent Variables: Dependent variables used to conduct this experiment include amount of yeast and sugar, beaker size, room temperature, and amount of water.
c. Control Of Variables: Some controlled variables in this experiment include the amount of yeast and sugar needed for each solution. Each of these were measured out by a scale in order to provide precise measurements. The temperature of the water was controlled by using a thermometer to ensure accuracy of each temperature. The size of each flask was the same for each solution of yeast,sugar, and water. The flask were also labeled with the corresponding temperature of water it contained.
Materials
:

Brandon4

1. Water kettle
2. Funnel
3. Thermometer
4. Ruler
5. Scale (grams, if available)
6. Erlenmeyer Flask-5
7. Beakers
8. Graduated Cylinder
9. Sugar
10. Yeast
11. Stopwatch

Method
: The objective of this lab was to measure yeast respiration based on five independent variables. To obtain this objective for this lab the following procedures where conducted. Five solutions were prepared with 15.00g of yeast and 20.00g of sugar each. To prepare the grams of yeast and sugar a scale was provided to weigh out the measurements without adding the additional weight of the beaker.A funnel was used to provide a clean distribution of the sugar and yeast from the beaker to the erlenmeyer flask. Water was heated in a kettle in order to get a variation of temperatures, ice was added to the hot water in order to decrease the temperature more rapid. When the suitable temperature was achieved, the water