3) Conditions: 18-25℃, sealed and periodically deflated (CO2).
4) Detection: Under acidic conditions, the reaction between potassium dichromate and alcohol is grayish green.
1) principle: Acetobacter has aerobic respiration.
O2, when the sugar source is sufficient, the sugar is decomposed into acetic acid.
When O2 is sufficient and sugar sources are scarce, ethanol will be converted into acetaldehyde and then into acetic acid.
C2H5OH+O2CH3COOH+H2O
2) Conditions: 30-35℃, introducing sterile air in time.
1) strains: Penicillium, Yeast, Aspergillus, Mucor, etc. , mainly Mucor (whole fungus).
2) Principle: Protease produced by Mucor decomposes protein in tofu into small peptides and aa? ; Lipase hydrolyzes fat into glycerol and fatty acids.
3) Conditions: 15- 18℃, maintaining a certain humidity.
5) Salt should be added layer by layer when curing, and the salt content should increase with the increase of layers. Salt can inhibit the growth of microorganisms and avoid the deterioration of tofu blocks.
1) principle: anaerobic respiration of lactic acid bacteria, reaction formula: C6H 12O62C3H6O3+ energy.
2) Production process: ① Prepare fresh water and salt into brine according to the mass ratio of 4: 1, and boil and cool the brine. Boiling is to kill miscellaneous bacteria, and cooling is to ensure that the life activities of microorganisms such as lactic acid bacteria are not affected. (2) Put fresh vegetables in salt water and cover the jar. Fill the tank at the edge of the tank cover with water to ensure the anaerobic environment for lactic acid bacteria fermentation.
3) Determination of nitrite content:
Methods: Colorimetry;
② Principle: Under the condition of hydrochloric acid acidification, nitrite reacts with sulfanilic acid, and then combines with N- 1- naphthylethylenediamine hydrochloride to generate a rose dye.
1. Types of media: solid media and liquid media according to physical properties, synthetic media and natural media according to chemical composition, and selective media and differential media according to uses.
2. The composition of culture medium generally contains water, carbon source, nitrogen source and inorganic salt P 14.
3. Microorganisms grow on the surface of solid culture medium and can form colonies visible to the naked eye.
4. The culture medium should also meet the requirements of microorganisms for PH, special nutrients and O2.
5. The key to obtain pure culture is to prevent the invasion of foreign bacteria.
6. Commonly used sterilization methods include: burning sterilization, sterilization of inoculation tools such as inoculation rings and needles; Dry heat sterilization: such as glassware, metal utensils and other items that need to be kept dry. Autoclave sterilization: sterilization of culture medium, for example.
7. Purification and cultivation of Escherichia coli with solid culture medium can be divided into two steps: preparation of culture medium and purification of Escherichia coli.
8. Preparation of solid culture medium: calculation → weighing → melting → sterilization → pour plate.
9. Commonly used inoculation methods of microorganisms: plate scribing method and dilution coating plate method.
10, the plate streaking method is to gradually dilute and disperse the bacteria on the surface of the culture medium through continuous streaking, and the dilution coating plate method is to dilute the bacteria solution according to a series of gradients and coat it on the surface of the culture medium respectively. When they are diluted to a certain extent, microorganisms will disperse into single cells, thus forming a single colony on the culture medium.
1 1. Microbe counting methods: live bacteria counting method, microscope direct counting method and filter membrane method.
12, viable count method is a colony growing on the surface of the culture medium when the sample dilution is high enough, which comes from a viable bacterium in the sample dilution. By counting the number of colonies on the plate, we can infer how many live bacteria are contained in the sample. The statistical number of colonies is often lower than the actual number of live bacteria. Because when two or more cells are connected together, only one colony can be observed on the plate.
13, microscope direct counting is also a commonly used method to determine the number of microorganisms, but it includes dead microorganisms.
14. The main purpose of setting control is to exclude the influence of non-test factors in the experimental group on the experimental results. Improve the credibility of experimental results. ① How to prove whether the culture medium is polluted: the culture medium in the experimental group is inoculated with microorganisms to be cultured, and the culture medium in the control group is inoculated with distilled water (blank control). ② How to prove whether a selective medium has selective function: the experimental group uses selective medium, while the control group uses ordinary medium (beef sauce peptone medium). If the number of colonies in ordinary culture medium is obviously larger than that in selective culture medium, it shows that selective culture medium has selective function.
15. How to isolate bacteria that decompose urea? Urea is the only nitrogen source in the culture medium, and phenol red indicator is added. If the PH value increases, the indicator turns red, and it is preliminarily identified that the strain can decompose urea.
16, how to isolate cellulose-decomposing microorganisms? Culture medium with cellulose as the sole carbon source.
17. Cellulase is a compound enzyme, which includes at least three components: C 1 enzyme, CX enzyme and glucosidase. The first two enzymes decompose cellulose into cellobiose, and the third enzyme decomposes cellobiose into glucose.
18. Screening method of cellulose decomposing bacteria: Congo red staining method. Its principle is that Congo red can form a red complex with polysaccharides such as cellulose, but it does not react with hydrolyzed cellobiose and glucose. When cellulose is decomposed by cellulase, Congo red-cellulose complex cannot be formed, and a transparent circle centered on cellulose decomposing bacteria will appear in the culture medium. (Transparent circles are generated, indicating that cellulose is decomposed, indicating that there are cellulolytic bacteria. )
1. In tissue culture of chrysanthemum, the newly sprouted lateral branches above the stems of non-flowering plants are generally selected.
2. The commonly used culture medium is MS culture medium: the main components include: a large number of elements: N, P, K, Ca, Mg, S; Trace elements: boron, manganese, copper, zinc, iron, molybdenum, iodine and cobalt; Organic matter: such as glycine, nicotinic acid, inositol, vitamins and sucrose, and plant hormones are often added.
3. Auxin and cytokinin are key hormones to start cell division, dedifferentiation and redifferentiation.
1) in different order will get different experimental results.
① Use auxin first, then cytokinin: it is beneficial to cell division, but cells do not differentiate;
② Cytokinin first, then auxin: cell division and differentiation.
③ Simultaneous use: the frequency of differentiation increased.
2) The dose ratio of the two affects the development direction of cells:
4. Pollen is a haploid germ cell, and its development goes through microspore tetrad stage, mononuclear stage and binuclear stage.
5. There are usually two methods to produce pollen plants (haploid plants) by anther culture:
Which route mainly depends on the type and concentration ratio of hormones in the culture medium.
6. Factors affecting anther culture: the selection of materials and the composition of culture medium, in addition, the growth conditions of parent plants, low temperature pretreatment of materials, inoculation density and so on all have effects.
7. Generally, the pollen of early flowering stage and mononuclear stage is selected for Chinese rose medicinal culture. When selecting anthers, it is generally determined by microscopic examination whether the pollen is in a suitable development stage. A common method for determining pollen development period: magenta acetate method. The pollen core of some plants is not easy to be colored, so it is necessary to dye the pollen core blue-black by baking blue chrome alum.
1, pectinase function: decompose pectin, disintegrate plant cell wall and intercellular layer, improve juice yield and make juice clear.
2. Pectinase does not refer to an enzyme, including polygalacturonase, pectinase and pectinesterase.
3. The activity of enzyme can be expressed by the decrease of reactants or the increase of products per unit time and volume.
4. At present, there are four commonly used enzyme preparations: protease, lipase, amylase and cellulase, among which alkaline protease and alkaline lipase are the most widely used and have the most obvious effect.
5. Action principle of enzyme-added washing powder: Alkaline protease can hydrolyze macromolecular protein contained in blood stains and milk stains. Converted into soluble amino acids or small molecular peptides, making stains easily fall off clothes. Similarly, lipase, amylase and cellulase can also hydrolyze macromolecules such as fat, starch and cellulose into small molecules.
6. Immobilization technologies include embedding method, chemical bonding method and physical adsorption method. Generally speaking, enzymes are more suitable for immobilization by chemical combination and physical adsorption, while cells are mostly immobilized by embedding method. Because the cells are large, the enzyme molecules are small; Large cells are difficult to be adsorbed or combined, while small enzymes are easy to leak from the embedding material.
7. When yeast cells are immobilized, distilled water is used for activation of yeast cells; When preparing sodium alginate solution, heat it with small fire or intermittently; The sodium alginate solution should be cooled to room temperature, and then the activated yeast cells should be added. Calcium chloride solution is beneficial to the formation of stable structure of gel beads.
1. The basic idea of extracting biological macromolecules is to select certain physical or chemical methods to separate biological macromolecules with different physical or chemical properties.
2. Solubility of DNA: ①DNA has different solubility in different concentrations of NaCL solution. In 0. 1.4 mol/L NaCL solution, the solubility is the smallest. ②DNA is insoluble in alcohol.
3. Tolerance of DNA to enzyme, high temperature and detergent: Because enzyme is specific, protease can hydrolyze protein, but it has no effect on DNA. DNA is more resistant to high temperature. Detergents can disintegrate cell membranes, but have no effect on DNA.
Under the condition of boiling water bath, DNA will be dyed blue when it meets diphenylamine.
5. Chicken blood is generally used to extract DNA instead of pig blood, because mature red blood cells of mammals (pigs) have no nucleus and no DNA.
6. When breaking chicken blood cells, you can add a certain amount of distilled water, stir with a glass rod, filter and collect the filtrate.
7. In order to purify the extracted DNA, it is necessary to further treat the filtrate. Add NaCL to the filtrate to make its concentration 2mol/L, filter to remove insoluble impurities, then add distilled water to make the concentration of NaCL 0. 14mol/L, separate out DNA, and filter to remove impurities in the solution.
8. Add 95% cold alcohol solution to the NaCL solution in which DNA is dissolved, so as to extract DNA with less impurities.
9.PCR principle: DNA replication in vitro
10, PCR conditions: ① a certain buffer; ②DNA template; (3) two primers are respectively combined with two template chains; ④ Four deoxynucleotides; ⑤ thermostable DNA polymerase; ⑥ Instruments and equipment for controlling temperature.
1 1. Why do you need a primer? Because DNA polymerase can't synthesize DNA from scratch, it can only extend DNA chain from 3' end. The synthetic direction of DNA always extends from the 5' end to the 3' end of the sub-chain.
12, PCR three steps: denaturation, renaturation and extension. Pre-denaturation is usually needed before PCR cycle to increase the possibility of complete denaturation of macromolecular template DNA.
13, the result of PCR: the DNA sequence between the two primers was specifically copied, so that this fixed-length sequence was amplified exponentially.
14, DNA has a strong absorption peak at 260nm.
15, protein separation methods: gel chromatography and electrophoresis.
16, gel chromatography is an effective method to separate protein according to its relative molecular weight. Protein with relatively small molecular weight moves slowly and then elutes; Protein, which has a relatively large molecular weight, moves fast and is the first to elute.
17. Electrophoresis makes use of the differences in charged properties of various molecules in the sample to be separated and the differences in the size and shape of the molecules themselves, so that charged molecules have different migration speeds, thus realizing the separation of various molecules.
6. Extraction of effective components from plants.
1. Extraction methods of plant aromatic oil: distillation, pressing and extraction.
2. Steam distillation method is to take out volatile plant aromatic oil with steam to form oil-water mixture, and then separate oil layer and water layer again after cooling. Such as rose oil and peppermint oil. (Extraction can also be used).
3. Squeezing method is often used to prepare citrus and lemon aromatic oil, because distillation in water will cause raw materials to scorch and the effective components to hydrolyze.
4. Carotene is usually extracted by extraction. The extraction method is to soak the crushed and dried plant raw materials in an organic solvent to dissolve the aromatic oil in the organic solvent, and then evaporate the organic solvent to obtain pure plant aromatic oil.
5. Petroleum ether has a high boiling point, which can fully dissolve carotene and is insoluble in water, so it is suitable as an extracting agent for carotene.
6. Rose essential oil is chemically stable, insoluble in water, soluble in organic solvents, and can be distilled by steam. Therefore, it is suitable for distillation.
7. The purpose of adding NaCL to the oil-water mixture of rose essential oil is to increase the density of water layer and separate oil from water. After the oil layer is separated, anhydrous Na2SO4 is added to remove water, and then Na2SO4 is removed by filtration.
8. Soak the orange peel with lime water before squeezing to destroy the cell structure, decompose pectin, prevent the orange peel from slipping during squeezing and improve the oil yield.
9. Carotene is an orange crystal with relatively stable chemical properties. Insoluble in water, slightly soluble in ethanol, easily soluble in organic solvents such as petroleum ether, suitable for extraction.
10. Water bath heating is used in the extraction process to prevent combustion and explosion of organic solvents. The bottle mouth is equipped with a reflux condensation device to prevent the organic solvent from volatilizing during heating.