(1) The metabolic type of yeast is heterotrophic and facultative anaerobic; alcohol can be detected with acidic potassium dichromate solution; the student needs to loosen the bottle cap every 12 hours or so. , but do not open it. The purpose of this is to discharge the CO2 gas in time and prevent the yeast from performing aerobic respiration and the fermentation liquid from being contaminated by miscellaneous bacteria.
(2) Reverse transcription is a process of synthesizing DNA using mRNA as a template. Therefore, reverse transcription is required to obtain cDNA. Therefore, the mRNA of the amylase gene is obtained from the filamentous fungus; after obtaining the target gene, a large amount of amplification is performed. Then insert it into the plasmid to construct a gene expression vector and introduce it into Saccharomyces cerevisiae in order to obtain Saccharomyces cerevisiae that can quickly decompose starch. To detect whether amylase is synthesized by Saccharomyces cerevisiae, the antigen-antibody hybridization method can be used.
(3) In order to screen out transgenic Saccharomyces cerevisiae that can efficiently utilize starch, the engineered strain was inoculated on a solid plate culture medium with starch as the only carbon source. After culturing for a certain period of time, iodine solution was added. ; Amylase can catalyze the hydrolysis of starch to form a transparent circle, so colonies with large transparent circles should be selected for further purification and culture.
(4) In order to understand the changes in the population during the purification culture process, a student measured the yeast population in the culture medium with a constant volume and concentration for 7 consecutive days. He needed to use 7 test tubes to culture and continue to separate them. The measurement can avoid the influence of the previous drawing of yeast culture liquid on the subsequent determination of yeast quantity.
A. Put an appropriate amount of dry yeast into a test tube containing a certain concentration of glucose solution, and culture it under appropriate conditions. A is correct;
B. After shaking well, use The pipette sucks the culture medium from the test tube, B is wrong;
C. Cover the cover with a cover glass first, and then put a drop of culture medium in the center of the hemocytometer, C is wrong;
D . Use filter paper to absorb excess culture fluid from the edge of the hemocytometer counting plate. D is correct;
E. Place the counting plate in the center of the stage. Wait for the yeast to settle to the bottom of the counting chamber and observe and count it under a microscope. , E is correct.
So choose: ADE.
(5) In the operation of preparing immobilized yeast cells, the most critical step is to prepare sodium alginate solution. The enzyme molecules are very small and can easily leak out of the embedding material, so this method should not be used when preparing immobilized enzymes. The purpose of treatment with CaCl2 solution is to facilitate the formation of gel beads (Ca2 reacts with sodium alginate to form water-insoluble calcium alginate gel).
(6) The microorganism used in the production of fruit vinegar is Acetobacter, and the temperature needs to be controlled within the range of 30-35°C.
So the answer is:
(1) Heterotrophic facultative anaerobic type? Acidic potassium dichromate discharges CO2 gas in time and prevents yeast from aerobic respiration and fermentation liquid Contaminated by bacteria.
(2) Antigen-antibody hybridization of mRNA gene expression vector
(3) Large transparent circle using starch as the only carbon source
(4) Avoiding the previous The impact of one-time aspiration of yeast culture fluid on subsequent determination of yeast quantity ADE
(5) The enzyme molecules prepared in the sodium alginate solution are very small and easily leak out from the embedding material, which is conducive to the formation of gel beads (Ca2 Reacts with sodium alginate to form water-insoluble calcium alginate gel)
(6) Acetobacter ?30-35