Cellular Respiration Model Use the space below to develop an input-output model that represents what you learned about the process occurring in the yeast from data you collected during the yeast respiration lab. ● Inputs (reactants) are anything that we added to the beaker ● Outputs (products) are anything that came out of the yeast as a result of a process ● Structures are parts of the system Now that you have a model, we are going to see how accurate it is! While you read, make the following notes (annotations) in the text: Highlighter This information confirms your model. Underline This information contradicts your model. Circle This information should be added to your model. Cellular Respiration in Yeast What Is Yeast? Have you ever baked fresh bread? It is a simple process in which a baker combines sugar, yeast, water, and flour together to make dough. However, baking bread does take some time. After the ingredients have been combined, the dough needs time to rise. This is where the yeast does its job. Yeast is a single-celled fungus. Yeast consume the sugar in the dough mixture as their food, producing carbon dioxide as a waste product. The carbon dioxide, a gas, makes the bread rise. When the bread is baked, the gas pockets in the bread give it the fluffy consistency people love. What Is Cellular Respiration? Yeast are unicellular (single-celled) organisms. Although humans are multicellular, we undergo many of the same cellular processes as yeast - including cellular respiration. Through cellular respiration, cells generate Adenosine Triphosphate, known as ATP, a molecule that stores chemical energy. When the yeast consume the glucose (a type of sugar) in the dough, they convert the energy in the sugar into ATP, which they use to fuel their own life processes. In the same way, human cells take in glucose and, through respiration, produce ATP molecules to store energy. Cellular respiration in eukaryotic cells occurs mainly in the mitochondria. In prokaryotic cells, it occurs in the cytoplasm. All organisms use cellular respiration to produce ATP. Cells break down ATP to release energy, in order to carry out life processes including growth, movement, making molecules, and transporting molecules. Aerobic and Anaerobic Respiration The yeast start the process of respiration by using available oxygen. This is called aerobic cellular respiration. Oxygen and glucose are converted into ATP, releasing the waste products of carbon dioxide and water. Our own cells use this process to extract energy from the food we eat, that is why we exhale carbon dioxide and water as waste products (just like the yeast!). Next time you hold up a mirror and breathe, you can see the water vapor collecting on the mirror - this is one of the waste products from generating ATP from glucose. When the yeast run out of oxygen, they still need to generate ATP, so they switch to anaerobic respiration, which does not require oxygen. The cells convert the glucose into ATP, generating carbon dioxide and lactic acid as a waste product. However, this type of respiration is not as efficient as aerobic, and produces less ATP. Anaerobic respiration happens in human cells as well; lactic acid build-up causes a burning sensation in muscles that often comes with hard exercise. Sources: http://study.com/academy/lesson/cellular-respiration-in-yeast.html; https://en.wikipedia.org/wiki/Cellular_respiration Cellular Respiration Summary Thinking about the partner work, group work, and class discussion: 1. One thing that went well in the discussion was… 2. One thing we can improve the next time we have a discussion is… 3. One person who helped me learn today was ____________________________. a. What did you learn from this person? 4. One idea that I contributed to my group or my class was… Thinking about the topic discussed today… 5. Why do people breathe harder or faster during exercise? Words → Model →
