The real intellectuals should have a set of bones, not good to tend to the trend. This makes the vast majority of them appear to be a color, always stand out from the crowd, not mixed into the pile of people. Here I share with you some high school biology fruit wine and vinegar production knowledge, I hope to help you, welcome to read!
High School Biology Fruit Wine and Fruit Vinegar Production Knowledge
1, fermentation: the process of producing large quantities of metabolites through the cultivation of microbial technology.
2, aerobic fermentation: acetic acid fermentation glutamate fermentation - anaerobic fermentation: alcoholic fermentation lactic acid fermentation
3, yeast is a parthenogenetic anaerobic bacterial microbial fungi - yeast reproduction: budding reproduction (mainly) schizogamy reproduction sporulation
4, in the presence of aerobic conditions, yeast carries out aerobic respiration and reproduce in large numbers.
C6H12O6+6O2+6H2O→6CO2+12H2O+energy
5. Under anaerobic conditions, yeast can carry out alcoholic fermentation.
C6H12O6→2C2H5OH+2CO2+energy
6, around 20 ℃ is the most suitable for yeast reproduction Alcohol fermentation is generally controlled at a temperature of 18 ℃ -25 ℃
7, in the process of natural fermentation of wine, play a major role in the wild-type yeast attached to the surface of the skin. During the fermentation process, as the alcohol concentration increases, the pigment of the red grape skins also enters the fermentation liquid, making the wine show a deep red color. Yeasts can grow and reproduce in an oxygen-poor, acidic fermentation broth, while most other microorganisms are constrained by their inability to adapt to this environment.
8, acetic acid bacteria are unicellular bacteria (prokaryotes), metabolic type is heterotrophic aerobic, reproduction mode for bifurcation
9, when the oxygen, sugar source are sufficient, acetic acid bacteria will be in the juice of the sugar decomposition of acetic acid; when there is a lack of sugar, acetic acid bacteria will be changed from ethanol to acetaldehyde, and then the acetaldehyde into acetic acid.
C6H12O6+2O2→2CH3COOH+2CO2+2H2O
C2H5OH+O2→CH3COOH+H2O
10, the role of controlling the fermentation conditions:
① Acetobacter is particularly sensitive to the content of oxygen, when carrying out the deep fermentation, even if it is just a short period of time interrupted by oxygen, will cause acetic acid bacteria death. will also cause the death of acetic acid bacteria.
② Acetic acid bacteria optimal growth temperature of 32 ℃, control the fermentation temperature, so that the fermentation time is shortened, but also to reduce the chance of contamination of stray bacteria.
③ There are two ways to generate acetic acid: direct oxidation and oxidation with alcohol as the substrate.
11, the experimental process: selection of grapes → rinse → juice → alcoholic fermentation → fruit wine (→ acetic acid fermentation → fruit vinegar)
12, the alcohol test: fruit juice fermentation whether there is alcohol production, you can use potassium dichromate to test. Under acidic conditions, potassium dichromate reacts with alcohol to present a gray-green color. First add 2mL of fermentation solution in a test tube, and then drop the concentration of 3mol/L of H2SO43 drops, shaking and mixing, and finally add 3 drops of saturated potassium dichromate solution at room temperature, oscillate the test tube, observe the color.
13, the aerating port is connected to the aerating pump for aerating during acetic acid fermentation; the exhaust port is used to discharge carbon dioxide during alcoholic fermentation; the discharge port is used for sampling. Exhaust port to be connected to the bottle through a long and curved hose, its purpose is to prevent airborne microbial contamination. The purpose of the opening downwards is to facilitate the discharge of carbon dioxide. When using this device to make wine, the filling port should be closed; when making vinegar, the filling port should be connected to an air pump to input oxygen.
High School Biology Fruit Wine and Vinegar Production Knowledge
01 Do you think the grapes should be rinsed first or the stems should be removed first? Why?
The grapes should be rinsed first, and then the stems should be removed in order to avoid the breakage of the grapes caused by the removal of the stems, which will increase the chance of contamination by stray bacteria.
02 What do you think should be done to prevent the fermentation broth from being contaminated?
Such as: to rinse the grapes first, and then remove the stems; juicer, fermentation device should be cleaned, and alcohol disinfection; each time the exhaust only need to loosen the bottle cap, do not completely open the bottle cap and so on.
03 When making wine, why should the temperature be controlled at 18 to 25 ℃? When making grape vinegar, why should the temperature be controlled at 30 to 35 ℃?
Temperature is an important condition for the growth and fermentation of yeast. 20℃ is the most suitable for yeast reproduction. Therefore, it is necessary to control the temperature within its optimal temperature range. Acetobacter is a thermophilic bacteria, the optimal growth temperature is 32 ℃, so it is necessary to control the temperature at 30-35 ℃.
High School Biology Review Tips
1. Collect information.
For example, the teacher's view of the trend of the college entrance examination, expert evaluation, etc., in the process of studying these materials, the focus of the college entrance examination for biology to do in mind, if possible, to be able to properly predict the college entrance examination topics, but not indulge in it.
2. Basic training to improve ability.
After mastering the textbook, we should utilize the test questions to consolidate. As can be seen from the college entrance examination questions in recent years, basic topics have always occupied a major position. So it is not necessary to choose the more difficult topics, but must cover all the knowledge points, and the implementation of carpet, net combing, do not leave any dead ends. Definitely not slapdash much less repeat knowledge points like fried rice. These contents require students to invest a lot of time and energy.
3. Build a knowledge network.
We know that the concepts, nouns, and terms of biology are relatively large, and they are also the key content to be examined in the examination. But their distribution is relatively fragmented.
How to y understand the connotation and extension of each concept, and master the relevant formulas, principles, physiological processes? It is recommended to classify, compare, summarize, etc., the use of a more graphic way, including drawing diagrams, tables, knowledge network diagrams, etc. to build a knowledge network, after building out the need to find a teacher to modify, or can be compared with other students, mutual guidance, mutual promotion.
4. After each test, analyze the test questions first.
The same type of errors and problems are summarized and organized to understand the root cause of the error. For questions with more errors, analyze and discuss them from different perspectives such as positive and negative.
In the process of revision, students should pay attention to the use of biological perspectives to guide the revision and questions. We should pay attention to the experiment, understand the design intention of the experiment, and master the operation method of the experiment. A round of review can not be rushed, only a steady, solid basic knowledge, biological achievements in the next review of the rapid progress.
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