Question After phage infestation with E. coli

Option A only explains that the DNA molecule in the phage cell is used as a template to replicate more phage DNA, but the phage is not only composed of DNA, and it is not the DNA of the phage that ruptures the bacterial cell, but the new phage produced by using the material in the bacterial cell.

So option D is correct, not only can more phage DNA be copied using the DNA molecule inside the phage cell as a template, but E. coli provides 8 nucleotides and about 20 amino acids to synthesize the phage's DNA molecule and protein molecule.

The process should be: adsorption, invasion, macromolecule biosynthesis, assembly, release.

Among them, DNA is indeed obtained by replication. Proteins are newly synthesized.

The mistake is that phages are not cells.

The phage in A is not a cell at all, it proliferates in the host's cell (evil capitalism), hehe, so A is excluded, so D is chosen.

Bacteriophages replicate within E. coli and not only copy DNA but also need proteins to make up themselves.

If option A doesn't say phage cells, this option is also correct.

Bacteriophage is a general term for bacteria and viruses. Viruses have no cellular structure! Therefore, it is not called xx cells.

My opinion is the same as that of the same floor.

The host E. coli cells are placed in medium containing radioisotopes 35S or 32P, respectively, and the protein is labeled with 35S and the egg DNA is labeled with 32P. Host cells are labeled with 35s or 32p as they grow.

The bacteria labeled by 35S or 32P are then infected with T2 bacteriophage, respectively, and replicated and proliferated in these bacteria. Host cleavage interpretation releases many progeny phages, which are also labeled with 35s or 32p.

Next, the host bacteria that are not labeled with radioisotopes are infected with phages labeled with 35s or 32p, respectively, and the isotopes carried by the host cells are determined. Few host cells infected by 35s-labeled phages have 35s inside the cells, while most 35s appear outside the host cells.

In other words, the 35S-tagged phage protein coat does not enter the host cell but remains outside the cell after infecting the host cell. After the phage labeled by 32P infected the host bacterial cells, the isotopes of the host bacteria were measured, and it was found that 32P was mainly concentrated in the host bacterial cells. Therefore, when phages infect host bacterial cells, it is mainly DNA that enters the cells.

Principle: Phage T2 has a protein shell in which DNA is encased. When bacteriophage T2 infects E. coli, its tail adsorbs on the thallus.

Then, a large number of phages are formed in the bacteria, and after the bacteria are lysed, dozens or even hundreds of phages T2 are released that are the same as the original infected bacteria.

The experiment was divided into two groups, one group labeled the protein shell of the phage with 35s, and the result was that the radioactivity was in the supernatant, and the supernatant contained only phage particles, so the conclusion was: the protein shell of the phage did not enter the bacterial body.

The other group labeled the DNA of the bacteriophage with 32p, and as a result, radioactivity was in the precipitate, and it was concluded that the DNA of the phage entered the bacterium.

Overall, the experiment proves that the material that has continuity between the pre-posterity of the phage is DNA, which proves that the traits of the progeny phage are inherited through the DNA of the parent, and DNA is the genetic material of the phage.

Bacteriophage infection bacterial experiments, history of discovery of photosynthesis, pneumococcal transformation experiments, with sexual inheritance.

Topic: Analysis: Hershey and Chase's experiments with T2 bacteriophage to infect bacteria were used to label DNA and protein with radioisotopes, and then infected E. coli with both labeled phages, thus proving that DNA is genetic material; Rubin and Carmen used radioisotopes to label oxygen in water and carbon dioxide, respectively, to prove that all the oxygen released by photosynthesis comes from water; Based on experimental observations, Sutton proposed the hypothesis that genes are located on chromosomes, and did not set up control experiments. Avery designed a set of controlled experiments in which the DNA, proteins, and polysaccharides of S-type bacteria were mixed with R-type bacteria, and only DNA was transformed into R-type bacteria, proving that DNA is genetic material

Answer: Solution: A. Hershey and Chase's experiment of infecting bacterial Tuanming with T2 bacteriophage used radioisotopes to label DNA and protein respectively, and then used two labeled bacteriophages to infect E. coli respectively, which is equivalent to a set of control experiments, so A is wrong;

B. Rubin and Carmen used radioactive isotopes to label the oxygen in water and carbon dioxide respectively, and then used two sets of experiments (one group of water is radioactive, and one group of dioxide carbon is radioactive) to prove that all the oxygen released by photosynthesis comes from water, using control experiments, so B is wrong;

c. Sutton put forward the hypothesis that the gene is located on the chromosome based on experimental observation, and there is no control experiment, so C is correct;

D. Avery designed a set of control experiments to mix the DNA, proteins, and polysaccharides of S-type bacteria with R-type bacteria, and only DNA made R-type bacteria transform, proving that DNA is genetic material, and protein is not genetic material, so D is wrong

Therefore, C

1.Attachment: It is a highly specific interaction between the virus and the host, and the proteins on the outside of the virus can bind to special good receptors on the surface of the host.

2.Invasion: (The various phages are not the same, so it's hard to say.) Presumably, the early fitting first specifically binds to the cell wall, releases lysozyme, dissolves the cell wall into a small hole, and injects DNA into the cell. Some bacteriophage shells can also enter bacteria.

3.Replication: DNA synthesis of bacteria stops after the start of infection, and mRNA and protein synthesis also stops a few minutes later.

The phage uses its own DNA as a template, catalyzed by the host RNA polymerase, which replicates to form the phage mRNA, translates and forms the enzymes required for the phage, which can modify the host RNA polymerase, and the modified RNA polymerase can further transcribe the phage gene.

4.Assembly and release: The phage and shell proteins are assembled into mature, infective phage particles.

When released, two proteins can be produced, one is the phage-encoded protein that destroys the cytoplasmic membrane, and the other is the phage lysozyme. The former destroys the cell membrane, the latter destroys the cell wall of Chunpei, and then the host cell ruptures, and the virus is suddenly released explosively.

Escherichia coli infection experiments were carried out using cell culture technology and isotope labeling. Isotope labeling Isotopes can be used to trace the movement and changes of substances. Isotopically labeled compounds do not change their chemical properties, and scientists can trace isotopically labeled compounds to understand the detailed process of chemical reactions.

Using the isotope labeling method, phage T2 has a protein shell in which DNA is encased. When phage T2 infects E. coli, its tail adsorbs on the bacterium. Then, a large number of phages are formed in the bacterium, and after the bacterium is lysed, dozens or even hundreds of phages T2 are released that are the same as the original infected bacteria.

It is because DNA is inherited that there is radioactive material outside E. coli.

I remember that the experiment started with the labeling of the parental genetic material, and then the marker would be detected in the offspring.

Not necessarily. Any bacterium can be infected by bacteriophages.

Bacteriophages, also known as bacterial viruses, are a class of viruses that specialize in infecting bacteria. Like other viruses, phages are specific in infecting bacteria, one type of bacteriophage infects only one class or one type of bacteria, and does not infect other kinds of bacteria.

For example, E. coli phages can only infect E. coli and cannot infect other types of bacteria. Other species of bacteria also have bacteriophages that specialize in infection. For example, Corynebacterium glutamicum used in the production of glutamate (its monosodium salt is monosodium glutamate) has its own specific bacteriophage.

In the monosodium glutamate factory, if you do not pay attention to hygiene and disinfection of workshops, equipment, and environment, phage infection accidents may occur, and the fermentation bacteria in the fermentation tank will be completely infected by the phages and disappear (bacterial rupture), resulting in significant economic losses.

But this bacteriophage cannot infect E. coli or other bacteria. In the event of such a production accident, the factory usually strengthens sanitation and disinfection on the one hand, and replaces other types of production bacteria on the other hand, so that it will not be infected by this bacteriophage.

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