What is the post transcriptional processing of mRNA and the synthesis mechanism of apoB100 and apoB4

The transcription process includes initiation, extension, and termination.

Start RNA polymerase.

Correctly identify promoters on DNA templates.

A ternary initiation complex of enzymes, DNA, and nucleoside triphosphates (NTPs) is formed, from which transcription begins. The initiation region on the DNA template often contains a TataATG sequence, called a Pribnow cassette or P-cassette. Nucleoside triphosphate in the complex is generally GTP and rarely ATP, so the 5 terminus of the original transcript is usually guanosine triphosphate (PPPG) or adenosine triphosphate (PPPA).

The transcriptional priming region on eukaryotic DNA also has a prokaryotic DNA initiation region structure, and at -30 bp (i.e., 30 nucleotides upstream of the enzyme and DNA binding site.

, often denoted by -30, bp is the abbreviation of base pairs) also contains a tata structure, called a hogness box or tata box. The first nucleoside triphosphate is condensed with the second nucleoside triphosphate to form a 3-5 phosphodiester bond.

After that, the initiation phase ends and the extension phase begins.

The extension subunit detachs from the enzyme molecule, leaving the core enzyme to loosen the binding to the DNA, making it easier to move forward. Core enzymes have no template specificity and can transcribe any order on the template, including the intermediate order to be excised during post-transcriptional processing. Subunits that are detached from the core enzyme can also bind to other core enzymes and participate in another transcription process.

As the transcription continues to elongate, the DNA duplex is sequentially opened and accepts the new base pairing, and after the synthesis of new phosphodiester bonds, the core enzyme moves forward, and the used template closes again, reverting to the original double-stranded structure. In general, synthetic RNA strands have a high degree of faithfulness to the DNA template. The rate of RNA synthesis is 25 50 nucleotides in prokaryotes and 45 100 nucleotides in eukaryotes.

Termination Termination of transcription involves the cessation of elongation and release of RNA polymerase and synthesized RNA. in prokaryotes.

The end of a gene or operon usually has a stop sequence at the end, known as a terminator; This is where RNA synthesis ends. Prokaryotic cell transcriptional termination requires the help of a terminator (a protein made up of four subunits). Eukaryotes.

There may also be a signal of transcriptional termination on the DNA. It is known that the 3 ends of eukaryotic DNA transcription units contain AT-rich sequences such as AATAA(A) or ATTAA(A), and the TTTT sequence (usually 3 5 T) occurs after 0 30 bp, which may be related to transcriptional termination or the addition of poly A order at the 3 ends.

But his processing method is integrated processing, and then his synthesis mechanism is an automatically controlled synthesis mechanism.

I feel that this is still okay, and I don't know much about the others, I don't know much about them, anyway, I personally feel that this should be able to fight.

The ordinal number is the processing method after rotation, and the two proteins can be interchangeable and crossed, which should be helpful to the human body.

Describe the post-transcriptional processing and the two proteins.

The processing mode of M220 after transcription can be checked on the Internet.

A. Some shearing processes do not require the participation of enzymes with protein properties, and the chemical nature of enzymes is protein or RNA, so the shearing of these mRNAs is catalyzed by RNA, and A is correct;

B. Gene is a fragment of DNA molecule with genetic effects, a gene can be transcribed to form a variety of mRNA, can control a variety of traits of the organism, B error;

c. Most eukaryotic cell mRNA is only synthesized at a certain stage of ontogeny, and different mRNA is degraded at different rates after synthesis, indicating that mRNA production and degradation are related to the stage of ontogeny.

d. RNA is synthesized in the nucleus, so its shearing and processing are completed in the nucleus, so it is not completed in the ribosome, D is correct

Therefore, choose B

According to the title, "the remaining RNA still has the same catalytic activity as this enzyme", indicating that the chemical nature of the enzyme is RNA

Therefore, a

Answer: A transport RNA determines an amino acid, and the ratio of the number of amino acids to the number of deoxynucleotides in the gene is 1:6.

Preparation of mRNA from animal cells.

Preparation of mRNA from plant cells 1. The ability of mRNA to guide the synthesis of high molecular weight proteins in a cell-free translation system. The cell-free translation system, also known as the in vitro transcription-translation coupling system, is also called the crude lytic translation system because the system requires the preparation of cell-free extracts.

Preparation of cell-free extracts:

The cells are dissolved by mechanical, ultrasonic, osmotic pressure or with appropriate detergents, and then centrifuged at high speed to remove the plasma membrane and nucleus. This extract contains RNA polymerase, ribosomes, tRNA and an energy generation system.

In vitro cell-free translation systems for common sharpeners:

Rabbit reticulocyte system. Reticulocytes have no nucleus, and more than 90% of the proteins they synthesize are globins.

A. According to the stem information "some shearing processes do not require the participation of protein-like enzymes", it can be seen that the enzymes required for the cleavage of some initial RNA cannot react with the biuret reagent, A is wrong;

b. According to the stem information "the initial RNA transcribed by the gene can be processed into mRNA that translates different proteins through different methods of shearing", it can be seen that a gene may be involved in controlling a variety of traits of the organism, b is wrong;

c. According to the stem information "most eukaryotic cell mRNA is only synthesized at a certain stage of ontogeny, and different mRNA is degraded at different rates after synthesis", it can be seen that the production and degradation of mRNA are related to the stage of ontogeny, C is correct;

D. The shearing and processing of the initial RNA are completed in the nucleus, D is wrong, so C

A. The chemical essence of the enzyme is protein or RNA, and the question says that "some shearing processes do not require the participation of protein-like enzymes", then the shearing of these mRNAs is catalyzed by RNA, so A is correct;

B. According to the title, the initial RNA can be processed into mRNA that translates different proteins through different shear styles, so one gene may control a variety of traits in an organism, so B is correct;

c. According to the title, most eukaryotic cell mRNA is only synthesized at a certain stage of ontogeny, and different mRNA is degraded at different rates after synthesis, indicating that the production and degradation of mRNA are related to the stage of ontogeny, so C is correct;

D. The transcription process mainly occurs in the nucleus, so RNA is synthesized in the nucleus and good limbs, so its cutting and processing should also be completed in the nucleus, so D is wrong

Therefore, choose D

According to the title, "the remaining RNA still has the same catalytic activity as this enzyme", indicating that the chemical nature of the enzyme is RNA

Therefore, a

c We know that the messenger Huiheng RNA molecule is transcribed through a strand of genes on the DNA molecule, then the ratio of the base containing the nuyl in the messenger RNA molecule is corresponding to the base ratio of the template strand, according to the title, U accounts for 20, A accounts for 10, then the gene template strand or a T accounts for 30 of the strand. According to the principle of base complementary pairing, the ratio of A+T in one strand of the gene to the chain is equal to the ratio of A+T in the other strand to the other chain and the ratio of A+T in the whole gene, that is, A+T in the whole gene accounts for 30 of all bases, then G+C accounts for 70 of all bases, and because of GC, cytosine C accounts for 35. 