How is Yeast a living thing?
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Yeast is a single cell organism that follows the rules:\n\nIt consumes sugars, and expels the waste as alcohol and carbon dioxide.\n\nIt reproduces, parthenogenically.
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It depends on what your definition of a "living" organism is.  Life probably started out as something like a self replicating organic molecule...like a prion.  Early "life" was probably indistinguishable from basic organic chemistry.           Your question didn't ask about the origin of molecules, just the origin of the first life forms.
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bacteria, yeasts, and internal parasites \n\nthey dont require Oxygen
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yeast is a fungus\nits a single celled organism
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Even among biologists, there is some debate about what constitutes being "alive", mainly because of viruses. There are four main criteria which are generally accepted. A living organism should:\n\nHave some kind of metabolism (processing "food" into "waste")\nGrow, change or evolve in its lifetime and generations\nInteract with its environment\nReproduce\n\nI would add to this that living things should have a determinate lifespan (that is, they die) and they should use DNA or RNA as a genetic template.
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Products produced by fermentation are actually waste products produced during the reduction of pyruvate to regenerate NAD+ in the absence of oxygen.\n\nWhen yeast ferments, it breaks down the sugar(C6H12O6) [including maltose] into exactly two molecules of ethanol (C2H6O) and two molecules of carbon dioxide (CO2).\n\nIf more detail is needed, see the second link on glycolysis, and if you need a LOT of detail, the third link on the Citric Acid cycle.\n\nNote that not all organisms can directly ferment maltose, some need to convert it into glucose first.
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Bacteria are capable of living alone. Viruses are said to be alive only when inside a living cell.\n\nBacteria have cell organelles and show life activities. Virus are just a core of DNA or RNA surrounded by a sheath of protein and can only show reproduction while in a living cell.\n\nBacteria are intercellular organisms( they live in-between cells ). Viruses are intracellular organisms ( they live within/inside cells )\n\nThere are many useful bacteria, that help in processes like nitrification and lactification. Viruses on the other hand are always disease causing. In fact, the term 'Virulesence', which is used for a disease causing organism, is derived from the word Virus'
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HEAT MAKES YEAST RISE\nCOLD KEEPS IT
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Yes... the live, active cultures found in yogurt are known as probiotics, or friendly bacteria.  They help to fight off candida, the bad bacteria found in a yeast infection.\n\nThe important thing to remember about yogurt is that the probiotics must still be live when you eat them in order for them to work... if the probiotics are dead, they aren't going to do much good.  It's not going to hurt anything, but you won't get the benefits.\n\nFrom the claims I've read, the probiotics in both of those yogurt brands are supposed to be live, so you should be fine with these.  Activia is my personal favorite.
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Fermentation is one of the oldest ways humans have used microbes. Fermentation is carried out by both bacteria (prokaryotes) and fungi (eukaryotes) during their metabolism. Both groups of organisms also figure in the world of human disease, as they are both sources of antibiotics, as we'll see throughout this module. \n\nFermentation results in a number of byproducts that have many different uses. The most well-known product of fermentation is ethyl alcohol. This substance is both a beverage as well as a starter molecule for synthesizing other compounds. Since fermentation is carried out in the absence of oxygen, we call it an anaerobic process. It is a method by which organisms such as yeast obtain their energy by converting sugars into other chemical compounds, particularly carbon dioxide and water. \n\nOur bodies also use this same anaerobic fermentation to obtain energy from sugars when oxygen is in low supply in our blood, such as during vigorous exercise. The products of this process are lactic acid and water rather than the carbon dioxide and water that human metabolism normally produces.
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with air yeast wil grow and thrive.\nwithout air it will produce ethanol and eventually die when the concentration of ethanol rises.
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They've got the starring role! Bacteria, fungi, protists, all of them pick away at whatever dead matter they find, and the important thing is that they often secrete digestive enzymes onto the stuff so it breaks down. This helps them have small food particles to ingest, and it cleans up the environment to boot.
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yes. too hot and you'll kill the bacteria.\ntoo cold and the yeast won't react.\nluke-warm water is perfect.\n\nyou also need to add sugar as 'food' (energy source) for the yeast.
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In bread and alcohol yeast is used for leavening and fermenting. Yogurt is cultured with different enzymes.
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Yeast has the ability to enzymatically convert simple sugars into Ethyl alcohol and Carbon dioxide.\n\nNormally this is a two step process.  The first step is the aerobic budding and multiplication phase where the yeast grows in numbers.  The second is an anaerobic phase where the actual fermentation takes place.\n\nThis is true for both baker's yeast (to leaven breads) and brewer's yeast (for alcohol production).  Yeasts are single-celled (unicellular) fungi, not bacteria.
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if it's not from fermentation, and the yeast is aerated, then it's gotta be from aerobic respiration.
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Yeast cells will use oxygen if it is present, and break down sugars all the way to CO2 and H2O.\nCO2 is expelled as a waste product from the yeast. You won't get tons of gas.\nThere is a piece of glassware called a fermentation tube but if you don't\nhave that, you can turn a small test tube upside down inside of another\nbigger test tube.  As the gas is generated it will be caught in the small\ntube.  You can measure the height of the bubbles with a metric ruler. That will give you the gas volume.