Why the primary mRNA transcript is so much shorter than chromosomal DNA?

Why is mRNA shorter than DNA? ➔ mRNA is the transcript of particular region of DNA, generally protein coding region and not of the whole DNA. It also does not contain sequences of exons from DNA. Thus mRNA is shorter than DNA.

Why do the RNA transcripts appear so much shorter than the length of DNA that encodes them?

Thus, the RNA molecules produced by transcription are released from the DNA template as single strands. In addition, because they are copied from only a limited region of the DNA, RNA molecules are much shorter than DNA molecules.

Why is the mRNA molecule shorter than the DNA molecule?

RNA is much shorter than DNA. Messenger RNA contains the information to make just one single polypeptide chain – in other words for just one protein, or even just a part of a protein if it is made up of more than one polypeptide chain. Overall structure. DNA has two strands arranged in a double helix.

What will be the length of the primary RNA transcript?

Studies of primary transcripts produced by RNA polymerase II reveal that an average primary transcript is 7,000 nucleotides in length, with some growing as long as 20,000 nucleotides in length.

How does transcription produce different mature mRNA transcripts?

Alternative RNA splicing The benefit of RNA splicing is that one gene can produce many different proteins as a result of what segments are treated as introns and exons. Different exons result in different mature transcripts and produce different proteins.

How is the mature transcript produced from the primary transcript?

As RNA polymerase breaks the bonds, it synthesises a primary transcript of mRNA using RNA nucleotides. These form hydrogen bonds with the exposed DNA strand by complementary base pairing. The primary transcript of mRNA is processed to produce a mature transcript of mRNA.

Why is it that the primary transcript in prokaryotes can immediately serve as mRNA?

Why is it that the primary transcript in prokaryotes can immediately serve as mRNA while in eukaryotes it undergoes elaborate multistep processing? (Select all that apply.) Prokaryotes do not have a nuclear envelope and the ribosome can start translation even before transcription ends.

How does DNA differ from RNA?

There are two differences that distinguish DNA from RNA: (a) RNA contains the sugar ribose, while DNA contains the slightly different sugar deoxyribose (a type of ribose that lacks one oxygen atom), and (b) RNA has the nucleobase uracil while DNA contains thymine.

Why is RNA less stable than DNA?

While DNA contains deoxyribose, RNA contains ribose, characterised by the presence of the 2′-hydroxyl group on the pentose ring (Figure 5). This hydroxyl group make RNA less stable than DNA because it is more susceptible to hydrolysis.

Why is RNA more reactive in comparison to DNA?

RNA is single stranded while DNA is double stranded. – RNA contains the deoxyribose sugar while DNA contains the deoxyribose sugar which means that DNA lacks one Oxygen containing hydroxyl group. As RNA is single stranded its nitrogenous bases are not away from the water, that makes it more reactive than that of DNA.

Why do most transcripts begin with an adenosine rather than one of the other Ribonucleotides which nucleotide is the second most common at the beginning of transcripts?

Why do most transcripts begin with an adenosine rather than one of the other ribonucleotides? Because RNA polymerase does not need a primer to transcribe DNA to RNA. Because of this, RNA polymerase needs a base pair that will form a weak bond, and the A:U base pair in RNA is the weakest.

What is the difference between primary RNA transcript and mature mRNA?

The initial product of transcription of a protein coding gene is called the pre-mRNA (or primary transcript). After it has been processed and is ready to be exported from the nucleus, it is called the mature mRNA or processed mRNA.

Why is mRNA shorter than DNA?

mRNA is the transcript of particular region of DNA, generally protein coding region and not of the whole DNA. It also does not contain sequences of exons from DNA. Thus mRNA is shorter than DNA. Privacy: Your email address will only be used for sending these notifications.

What are the similarities between ribosomal and transfer RNA transcriptions?

Primary transcripts of ribosomal and transfer RNA also require processing by nucleases, and there are similarities between prokaryotes and eukaryotes. Ribosomal proteins begin to associate with the primary transcript as it undergoes processing.

What is the difference between primary transcript and hnRNA?

Primary transcript. Once pre-mRNA has been completely processed, it is termed ” mature messenger RNA “, or simply ” messenger RNA “. The term hnRNA is often used as a synonym for pre-mRNA, although, in the strict sense, hnRNA may include nuclear RNA transcripts that do not end up as cytoplasmic mRNA.

Is there a post-transcriptional element in the DNA sequence?

Neither of these posttranscriptional elements has a counterpart in the DNA sequence. Splicing of eukaryotic primary RNA transcripts removes the introns, leaving the exons connected together in a functional message.