Lab Report

Introduction

Yeast is an organism used to make bread rise, but it is also used to makes beer and wine. In the experiment, we will see how different sugar types affect the Fermentation of yeast. Yeast is a single celled organism that is used to make dough rise and ferment alcoholic drinks like beer and wine. When you smell bread you mostly smell the scent of the yeast. There are hundreds of species of yeast but only a few of these are used commercially. Yeasts belong to a group of simple organisms known as fungi, which exist almost everywhere in nature. Yeasts reproduce rapidly, and they grow especially well in substances containing sugar. Depending of the type of sugar the yeast ferments with the outcome will be different types of alcohol. Maltose comes from grains and is used with yeast to make beer. Fructose comes from fruits and with yeast makes wine. Sucrose from sugar cane, rum and lactose which comes from milk, nothing. Glucose is the simplest sugar and in our testing we used it as a control.

Cell respiration is the process of converting different forms of energy to adenosine triphosphate (ATP), a form that living things can use. There are two types of cellular respiration, aerobic and anaerobic. Aerobic respiration requires the presence of oxygen, anaerobic respiration, or fermentation, does not. We were observing alcoholic fermentation which is anaerobic and does need oxygen. In fact it doesn't work with oxygen so we needed to keep it out. A simple equation for anaerobic respiration is glucose à alcohol + carbon dioxide. In the à part enzymes release ATP, energy that the living thing can use.

In our experiment we tested the fermentation of yeast with five different types of sugars. We tested fructose, sucrose, lactose, maltose and glucose as a control. We are trying to find out which type of sugar will ferment with yeast and produce the most CO2.

We are doing this to figure out which sugar gives the living thing (the yeast) the most energy. We will measure the CO2 in kpa/ second, pressure over time. I think that sucrose will produce the most CO2 because it is a complex sugar that is the most sugar like, unlike the other sugars which have grain and fruit roots.

Experimental Design

V: Sugar type

  

Glucose

 

Sucrose

 

Lactose

 

Fructose

 

1 trial 

 

1 trial

 

1 trial

 

1 trial

 DV: The rate of fermentation

Constants:

·        Water temperature between 37-40 °C in beaker

·        Amount of water in beaker, 15 mL

·        Length of experiment

·        Dialysis tube's distance from the probe

Procedure

Figure 1

Figure 2

1.  Set up lab station.  Figures 1+2

2.  Turn on the calculator and start the DATAMATE      program. Set up the calculator

 3.   Fill the beaker with 15 ml of water.  Keep temperature in beaker not between 37-40 °C.  If the temperature is below 37°C put on hotplate on low.  And if the temperature is above 40°C add cold water until correct temperature is reached.  

4.   Take two test tubes and label them 1 and 2.

Figure 3

5.   You will test the five sugar solutions; glucose, sucrose, lactose, fructose, and maltose.  Using a graduated cylinder place 2.5 mL of the sugar solution into the test tube ...