Is transcription an entire strand of DNA or a part of a strand

The key to transcription initiation is the interaction of RNA polymerase with the promoter.

A promoter is a DNA sequence located upstream of a structural gene that directs the correct binding of the RNA polymerase to the template, activates the RNA polymerase, and ensures an accurate and efficient initiation of transcription. The structure of the promoter affects its affinity with RNA polymerase, and also determines the selection and binding of RNA polymerase. Take Escherichia coli RNA polymerase as an example, this polymerase (holoenzyme) is composed of two parts: δ factor and core enzyme.

A factor is a protein factor that is specifically responsible for template chain selection and transcription initiation, and is an allosteric effector of the enzyme that enables the enzyme to specifically recognize the promoter on the template. The core enzyme is responsible for transcription, and the template recognized by the holoenzyme that has formed single-stranded DNA is recognized. It is because RNA polymerase must bind to a specific region of the DNA molecule, the promoter, that determines the site of transcription initiation.

Secondly, RNA polymerase, like DNA polymerase, can only catalyze the addition of single nucleotides to the polynucleotide strand with free 3-OH, that is, RNA synthesis can only synthesize RNA strands complementary to the DNA template strand in the direction of 5 3. This determines the direction of the transcription.

It is precisely because of this "locus" and "orientation" that together determine which strand of DNA will be transcribed, as opposed to both strands of DNA that can be transcribed into mRNA at the same time (although there are a few exceptions, such as the double strands of plasmid DNA in bacteria that can be transcribed in the same region at the same time).

In fact, along the basis of a DNA molecule, many genes are arranged, each with a promoter, and each promoter determines the direction of transcription of the gene, specifies the line of transcription, and the terminator. However, because genes are broken, adjacent genes are not completely continuously arranged on a transcription line, and the two strands of DNA have opposite chemical polarities. Excerpt from "Preparing for the Physiology Examination in Secondary School".

It's part of a chain, and what needs to be transcribed.

Neither strand of the DNA duplex can be translated into RNA as a transcription template.

The duplex of DNA cannot all be used to transcribe mRNA, only one strand can. There is a strand in DNA that has the same nucleohulinate sequence as mRNA, and this strand is called the coding strand; The DNA strand that guides mRNA synthesis and is complemented to mRNA is called a template strand or antisense strand.

Only the template strand (antisense strand) can be used to transcribe mRNA. The other strand (encoded strand) is only used for DNA replication.

The template is only used to generate another DNA strand and is not used for other purposes.

RNA polymerase.

By forming a dynamic complex with a series of components, the process of transcription initiation, extension, and termination is completed. The codons carried by the generated mRNA enter the nucleus segment into the ribosome.

Protein synthesis can be realized. Transcription only uses one strand of DNA as a template, and the single strand selected as a template is called the template strand, also known as the nonsense strand; The other single strand is called the non-template strand, that is, the coding strand, which is also called the sense strand because the coding strand is consistent with other sequences other than the transcribed RNA sequence T. The region of transcription on the DNA is called the transcription unit.

Summary. Because for the whole chromosome, transcription does not always follow a strand as a template. Of course, for a particular gene, the orientation is certain because there are promoters upstream of the coding region of the gene that control the start and direction of transcription.

Because for the whole chromosome, transcription does not always follow a strand as a template. Of course, for a particular gene, the orientation is certain because there are promoters upstream of the coding region of the gene that control the start and direction of transcription.

For example, let's say a DNA strand has 1 million base pairs (1-1,000,000).Gene A is encoded from 3000-5000 and the promoter is 2500-3000, and is transcribed according to the following strip of the duplex. Gene B is in the opposite direction, with the promoter at 5100-4100 and the gene coding region at 4100-3100

In this way, the two genes partially overlap, but in opposite directions.

Happy New Year to the teacher! Good night!

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Because the bases of the same DNA are complementary. You know one of the chains. The other chain is also known.

on the transcribed codon. The codons of the complementary bases are also the same. So just one chain is enough.

This saves material. It is formed by the long-term evolution of living things.

Why does a DNA molecule fragment have only one strand as a template when transcribing?

Because if the DNA double-strands are transcribed at the same time, two different proteins or functional RNAs will be produced at the same gene locus, which is a great waste of resources, and it will also cause confusion during assembly, and the error rate will be more than doubled (because it involves templates for various DNA repair mechanisms).

Answer]: B Test point] Asymmetric transcription of DNA [Analysis] In the DNA double strand, the single strand that leads to transcription and production of DNA according to the base pairing is called the template strand, and the other strand that complements it is called the coding strand. The nucleotide (or zygobase) sequence in the coding strand is consistent with that of mRNA, except that the rock is T and U exchanged.

The DNA sequences listed in the literature are generally coding strands, so B should be chosen. The template chain can also be referred to as the meaningful chain or the Watson chain. The coded chain header leak can also be referred to as an antisense chain or crick.