3. Which of the sample/s is/are fermented with difficulty? Which of the sample/s is/are easily fermented? Which are not fermented at all? Fermented w/ difficulty Easily fermented Not fermented at all
PLEASE HELP ME ANSWER THE TABLE THANK YOU
ACTIVITY NO. 3
ALCOHOLIC FERMENTATION
Introduction
The conversion of carbohydrate such as sugar into an acid or alcohol is called fermentation. Fermentation that uses yeast is termed as alcoholic fermentation.
Glucose --------à carbon dioxide and alcohol + energy
The enzyme in yeast catalyzes alcoholic fermentation which actually occurs as a two-step process. This process takes place under anaerobic conditions such as in the absence of oxygen liberating a small amount of energy. Some carbohydrates are not hydrolyzed to simple sugars by yeast under anaerobic conditions due to the lack of the specific enzymes needed to catalyze the reaction. Fermentation of simple sugars by yeast has different
- The first step involves the decarboxylation of pyruvate from glycolysis to acetaldehyde acted by the enzyme pyruvate decarboxylase.
- The second step is the reduction of acetaldehyde which is catalyzed by alcohol dehydrogenase producing ethanol and carbon dioxide as the end products.
Objectives: At the end of the activity, the student can:
- Compares the rate of fermentation of the different samples used.
- Identify which samples are readily fermented, fermented with difficulty
and not fermented at all.
Reagents: (8 ml each sample) 10% glucose, fructose, galactose, maltose, lactose, sucrose, xylose, starch solutions, 32 ml -10% yeast solution
Materials: 8 plastic cups , 8 test tubes (10 ml), dropper, ruler, 10 ml graduated cylinder, Test tube rack
Procedure:
- Obtain 8 clean test tubes and label them.
- Fill each tube 1/3 full with yeast suspension.
- Add sample to completely fill the tube.
- Hold filled tube upright.
- Place plastic cup on over the tube.
- Quickly invert the plastic cup. Be careful not to tip the tube. If procedure is correctly done, only a small air bubble will be present in the upper end of the tube.
- Measure the length of the air bubble if present. Note its length in millimeter. Record length as original bubble.
- Examine the tubes every 15 minute interval and measure length of any bubble as they develop and increase in size. Subtract the length of the original bubble from all new measurements to yield net bubble length. Continue observation over a 90 minute period.
- Plot your data in a graph. Use only 1 graph for all 8 samples
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