Formy experiment I will be using investigating how different concentrations ofglucose affect the rate of fermentation of yeast.
Yeast is actually a singlecelled fungus that is found in the natural environment. Its scientific name is Saccharomyces Cerevisiae and is alsoknown by people as “the sugar fungi”. Yeast has been used for more than 5,000years by early Egyptians who wrote hieroglyphics. Yeast was discovered afterthe design of one of the most elaborate microscopes created in the 1800’s. Thismicroscope helped scientists like Louis Pasteur to find out that yeast is aliving organism.
Over time, we learn that this yeast is used for alcoholfermentation and also helps bread rise easier. There are 600 types of yeastfound throughout nature within fungus. According to “RedStarYeast” yeast is aphase within fungus that is unicellular.
Also, yeast requires a carbon and nitrogensource, but this affects yeast because it cannot go through the process ofphotosynthesis. Some of the most important carbon and nitrogen sourcesthat are used are urea, biotin, and amino acids. Also, an interestingcharacteristic they have is that instead of using binary fission to divide theyuse a technique called budding.
As the bud is developed near the cell wall, itdetaches from the main cell into a smaller daughter cell. For each cell, thebudding process occurs about 15 times until it stops. The size of the yeastcells can be compared closely to the size of a red blood cell in a human’sbody. Some main functions of yeast are to help fermentation occur, causes therelease of carbon dioxide and ethanol, and helps bread maturation. Fermentationis also another important factor that is involved in my internal assessment.Fermentation is a metabolic and chemical breakdown of a substance by bacteria,yeast, and other organisms.
Yeast is used in fermentation to take the sugar outand produce oils, alcohol, and even different types of gases. Fermentation getsits energy from anaerobic cellular respiration because oxygen is missing fromthe process. Some factors that may affect fermentation is the concentration,temperature, composition, etc. Another factor that will affect my IA is theglucose I will be using. I will have 5 different concentrations for the amountof glucose I will be using each time I do a trial and see how it affects therate of fermentation. Glucose is a simple sugar that is most commonly found inthe bloodstream. Glucose has the ability to breakdown monosaccharides and alsosome disaccharides.
According toLivestrong.com “Glucose is the most common carbohydrate and nutrient in thebody.”Identification ofTopic: I chose to research for my internalassessment “How does different amounts of glucose affect the rate offermentation of yeast?” I chose to research this question because it is aninteresting topic and also because it’sa question that can help me understand and learn a new topic that can help furthermy understanding of topics like fermentation and concentration levels. Also,yeast has a scientific name which is SaccharomycesCerevisiae, this word translates to English as “sugar fungus”. The independentvariable of my experiment is the amount of glucose that will be used and mydependent variable is the rate of respiration (breakdown of sugar to retainenergy). After coming up with my question and variables I will be using, Icreated my own hypothesis about what will be the results from my experiment. Myhypothesis is the greater the concentration levels, the faster the rate ofrespiration will be.
The theory that influenced my decision about my hypothesisis the theory that Louis Pasteur created stating that discussed how spontaneousgeneration worked, but now this theory is not used anymore because the germtheory that was created had new and better findings. Relevance,reliability, and sufficient of data collection: The independent variable is theamount of glucose I will be using in my experiment. I will be manipulating myindependent variable by changing the concentration levels of each, since I wantto find out if concentration affects the rate of fermentation. I will be using5 different concentrations:0.5 grams, 1 gram, 1.5 grams, 2 grams, and also 2.5grams of glucose. My range of the different concentrations was chosen because Iwanted the amounts to be very different from one another, so I chose 0.
5 gramsas the smallest increment and 2.5 gram as the largest increment. The dependentvariable is the rate of respiration from the reaction. I will be using a CO2probe to detect the product of fermentation.
My controlled variables are theamount of yeast(5 grams), amount of water(20mL), room temperature, time, andprobes. These controlled variables can impact the results by making the amountof fermentation drastically different for each concentration. All of thesecontrolled variables will be held constant by using the measurements each timefor all the materials being used.Methodology: My plan to collect the dataaddresses the research question because I will be taking note of myobservations for each trial I complete. My method for recording results includedoing a table for each trial that I’ll write all my measurements in.
Then, inthe same table I’ll write my observations and record how much CO2 is releasedfrom the fermentation. I will record all my data in the same form for each ofthe trials I conduct. I will be using grams for measuring my yeast and glucose,degrees Celsius to measure temperature of the water, milliliters to measure water,and ppm for the pressure of the CO2 released. I will be using materials such astimers, flasks, scales, co2 probe, and thermometers in my experiment to measureout all my materials needed.Steps:1) Gatherall materials needed.2) Weighthe amounts of glucose on the scale to make sure you have the correct amountneeded (5 different amounts: 0.
5g, 1g, 1.5g, 2g, 2.5g)3) Weighout 5 grams of yeast on the scale.
4) Then,take a graduated cylinder and measure 20 ml of room temperature water.5) Onceyou have all of these materials measured out, you will then mix all of themtogether into an Erlenmeyer flask. Place the CO2 probe inside the flask andbegin measuring the rate of respiration every minute for 10 minutes.6) Afteryour solution has fermented for 10 minutes take the probe out of the flask.7) Makesure to record your data for each experiment.
8) Repeatsteps 2-7 for each of the 5 concentrations of glucose. You will be doing 3trials for each of the 5 concentration levels being tested.Safety and Ethics:There are no safety or ethicalconcerns that have to be addressed for my internal assessment.