Biology masters, please enter the following narrative about genetic engineering, which is correct

a.A marker gene is a gene with a known function or a known sequence that can play a specific role as a marker. In the sense of genetic engineering, it is an important marker for recombinant DNA vectors, which is usually used to test the success of transformation. In the sense of gene mapping, it is a tool for marking the gene of interest, which is usually used to detect the localization of the gene of interest in cells.

So a mistake. b.Reverse transcription is to use the messenger RNA transcribed from the target gene as a template, reverse transcribed into complementary single-stranded DNA (cDNA), and then synthesize double-stranded DNA under the action of enzymes to obtain the desired gene.

It is one of the important methods for extracting the target gene in genetic engineering.

Insulin can be extracted from pancreatic B cells, so messenger RNA can be extracted as a template.

So B right. c.Introducing the gene of interest into the recipient cell is the third step in implementing genetic engineering.

So C is wrong. d.Genetic engineering involves a wide range of tool enzymes, which can be roughly divided into four categories: restriction enzymes, ligases, polymerases, and modified enzymes. Among them, restriction endonucleases and DNA ligases play the most prominent role in molecular cloning.

So d wrong. I hope to answer your doubts about biology and hope to help you get good results in this subject!

If the target gene is selected incorrectly, it is only convenient to screen the target gene, but cannot promote the expression of the target gene.

B is correct, pancreatic B cells secrete insulin, so the cells contain messenger RNA that synthesizes insulin;

c Error, not a genetic mutation, but a genetic recombination;

D is false, not DNA polymerase, is DNA ligase.

Hope it helps. ^_

Select d The target gene and recipient cells in genetic engineering can be automated, plant or microorganism; Commonly used tool enzymes are restriction endonucleases and DNA ligases; The proinsulin expressed by the human proinsulin gene in Escherichia coli has no biological activity and is only biologically active after activation by a certain substance. The resistance gene on the vector is mainly beneficial for screening cells containing recombinant DNA, but cannot promote the expression of the target gene. So d is wrong.

A error bai

Genetic engineering is to get what people need

The gene expression of the zhi product dao

Antibiotics are made to mark genes back.

B correct plasmids.

It is very common to answer that small circular DNA is often used as a carrier c error, because the gene of interest is required to be inserted into the carrier, so both incisions need to be the same sticky end or blunt end.

To achieve this, it is necessary to cleave with the same restriction endonuclease d, and plant cells have high totipotency and can be directly introduced into somatic cells for plant tissue culture.

It is not necessary to import only fertilized eggs like animals.

I hope it will help you, if you don't understand, please ask.

Answer d In genetic engineering, the target gene and recipient cells can be automated, plant, or microorganic; Commonly used tool enzymes are restriction endonucleases and DNA ligases; The resistance gene on the vector is mainly beneficial for screening cells containing recombinant DNA, and it is not possible to determine whether it is on the chromosome, so D is wrong.

a. Genetic engineering is a genetic operation at the molecular level, not bioengineering at the cellular level, and a is incorrect;

b. The safety of genetically modified organisms is not yet certain, and the products of genetic engineering are not necessarily beneficial to humans, and b is incorrect;

c. The mutation generated by genetic engineering is transferred into a foreign gene, while the artificially induced mutation is the mutation of genes in the organism, so the mutation generated by genetic engineering is different from the induced mutation; c is incorrect;

d. One of the advantages of genetic engineering breeding is that it has a strong purpose and can improve traits in a targeted manner

Answer: Genetic engineering is bioengineering at the molecular level (DNA), and the specific operation process is: (1) obtaining the target gene; (2) binding of the target gene to the carrier; (3) introduction of corresponding recipient cells; (4) Detect whether it is expressed. This process does not belong to artificial mutagenesis, it belongs to genetic recombination, and has a strong purpose.

Examine the relevant content of genetic engineering.

The answer is: c.

A false, DNA ligase can only connect phosphodiester bonds, and cannot connect the base pairs of two viscous ends of base complementarity';

B is false, the target gene can also be obtained by artificial synthesis;

C is true, D is false, the use of marker genes on plasmids can only be used to screen cells containing recombinant DNA, not transgenic plants.

I choose CAnalysis:

In A, DNA ligases are phosphodiester bonds that link two deoxynucleotides, rather than hydrogen bonds between bases.

The gene of interest can be extracted directly from the gene library or obtained by PCR technology.

The marker gene in D is only suitable for screening cells, not for biological individuals.

Answer: The bases at the sticky ends of B are connected by hydrogen bonds, which are connected as long as they are close, and DNA ligases are connected to five-carbon sugars. The process of binding the target gene to the carrier is intracellular, scientists just inject the target gene and enzyme into the cell, and the commonly used carrier for genetic engineering is plasmid and phage, so option b is correct.