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The end of an mRNA molecule is referred to as a poly A tail because it is a segment composed of many Adenine nucleotides in a row (i.e. AAAAAAAA).
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The 3' poly-a tail is attached to?
mRNA
What is the purpose of the 5' cap and the 3' poly A tail?
5' cap helps protect mRNA from degradation by hydrolytic enzymes and after mRNA reaches the cytoplasm, the 5' cap functions as part of an "attach here" sign for ribosomes. The poly-A-tail inhibits degradation of RNA and helps ribosomes attach and facilitates export of mRNA from the nucleus.
How does the absence of a nuclear envelope in the prokaryotes prevent prokaryotes from controlling gene expression by modifying RNA after transcription?
In eukaryotes, mRNA is processed inside the nucleus before being shipped out into the cytoplasm for translation. Specifically, a strand of pre-mRNA (or immature mRNA) has a GTP cap added to its 5' end, a poly-adenine tail added to its 3' end, and it has its introns spliced out. Since prokaryotes don't have nuclear envelopes, they don't have an area to do this.
What is the significance of a polytail consisting of AAA at the end of a mRNA sequence?
The poly adenine tail is used to provide a fuse. This is because RNase enzymes cleave off a section of the nucleotides at the end of the mRNA strand. The destruction of the mRNA is to prevent it persisting within the cell after being used, the length of the tail shows how many times it will be used before being degraded.
How is mRNA stabilized before leaving the nucleus for translation?
Before leaving the nucleus, the mRNA is modified (post-transcriptional modification). It is protected from ribonucleases by adding a 5' cap and a (3') poly A tail. These modifications help to stabilise the mRNA by preventing degradation by nucleases.
The 3' poly-a tail is attached to?
mRNA
What is the purpose of the 5' cap and the 3' poly A tail?
5' cap helps protect mRNA from degradation by hydrolytic enzymes and after mRNA reaches the cytoplasm, the 5' cap functions as part of an "attach here" sign for ribosomes. The poly-A-tail inhibits degradation of RNA and helps ribosomes attach and facilitates export of mRNA from the nucleus.
What helps to stabilize mRNA by inhibiting its degradation?
5' cap and poly (A) tailPoly A tail at 3' end
What step in synthesis is transcription?
The excising of the introns from the mRNA and the adding of the poly A tail and guanine repeats to the mature mRNA so that it now exits the nucleus to begin translation.
What is the last step in transcription?
The excising of the introns from the mRNA and the adding of the poly A tail and guanine repeats to the mature mRNA so that it now exits the nucleus to begin translation.
What is a transcription and where does it occur?
transcription is the act of DNA being 'transcribed' into mRNA inside the nucleus. Afterwards, the head and tail of the mRNA get capped with a poly-A tail and a 5 prime cap in RNA processing, so that the mRNA doesnt get recognizede as a dangerous molecule. There, it is then shipped of out of the nucleus where the mRNA gets translated into tRNA in the ribosome to produce amino acids which will eventually be turned into proteins
When and at what end does the tailing of hnRNA take place?
The tailing of hnRNA, which involves the addition of a poly-A tail to the 3' end of the mRNA molecule, occurs after transcription and before the mRNA is released from the nucleus. This process helps stabilize the mRNA and facilitate its export to the cytoplasm for translation.
How does the absence of a nuclear envelope in the prokaryotes prevent prokaryotes from controlling gene expression by modifying RNA after transcription?
In eukaryotes, mRNA is processed inside the nucleus before being shipped out into the cytoplasm for translation. Specifically, a strand of pre-mRNA (or immature mRNA) has a GTP cap added to its 5' end, a poly-adenine tail added to its 3' end, and it has its introns spliced out. Since prokaryotes don't have nuclear envelopes, they don't have an area to do this.
What is the significance of a polytail consisting of AAA at the end of a mRNA sequence?
The poly adenine tail is used to provide a fuse. This is because RNase enzymes cleave off a section of the nucleotides at the end of the mRNA strand. The destruction of the mRNA is to prevent it persisting within the cell after being used, the length of the tail shows how many times it will be used before being degraded.
How is mRNA stabilized before leaving the nucleus for translation?
Before leaving the nucleus, the mRNA is modified (post-transcriptional modification). It is protected from ribonucleases by adding a 5' cap and a (3') poly A tail. These modifications help to stabilise the mRNA by preventing degradation by nucleases.
What are two ways that messenger RNA is processed prior to translation?
Not necessarily in this order: It gets a 5' modified guanine cap It gets a 3' poly-A tail It visits a spliceosome. The introns are removed. The exons may undergo "alternative splicing" in which some of them are removed too, and the rest are spliced together to make one mRNA.
What mechanisms of gene regulation operates after mRNA transcription but before translation of mRNA into protein?
There are two mechanisms as related to above. Firstly, the removal of All Introns occurs - via the Spliceosome -, and then a "poly AAAAAAA" tail is attached to the [edited] mRna transcript just before its export to the cytoplasmic Ribosomes.
