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What is the stop codon in most molecules of mRNA?
stop codon on mRNA
How does transcription end?
Transcription ends once the a termination sequence is reached. The sequence depends on which polymerase is being used and if the organism is a eukaryote or prokaryote. In Eukaryotes when RNA polymerase 1 is used the termination sequence is an 18 nucleotide long sequence. For RNA polymerase 3 the termination sequence is a short sequence of Uricils but the hairpin loop is not formed as it is in prokaryotes. For RNA polymerase 2 transcription is terminated and cleavage takes place 10-35 nucleotides downstream of the AAUAA sequence. For prokaryotes, termination can occur 2 ways. Termination can occur once the termination sequence is reached or using a protein called Rho factor. For termination without Rho factor, the termination sequence is short and rich in Guanines and Cytosines followed by many Uricils in a row. A-U bonds are weaker than G-C bonds, the string of U-A bonds are easily broken and release the RNA strand Using a Rho factor, once the Terminal sequence is reached, the Rho factor binds to a sequence 50-90 bases long and unwinds the DNA from the RNA , moving towards the 3' end, releasing the RNA
When does the polypeptide stop growing?
It reaches a stop codon on the mRNA molecule
A stop codon on an mRNA molecule does not code for any?
amino acid
Does transcription begin at a promoter region and continue until RNA polymerase reaches a stop codon?
yes,
How does RNA polymerase know where to start transcribing a gene into mRNA?
The enzyme that synthesizes RNA (RNA polymerase) binds specific DNA sequencesthat typically lie before the gene being transcribed. When everything it needs to start synthesis is properly assembled (any cofactors, etc.), only then can it begin transcribing DNA into RNA.
What is the stop codon in most molecules of mRNA?
stop codon on mRNA
What are the steps taken to translate a 9-base DNA strand into an amino acid sequence?
There are a huge number of steps involved in this process, but briefly it goes like this: # Transcription factors bind to DNA and promote binding of RNA polymerase # RNA polymerase binds in complex with transcription factors # Transcription is initiated and RNA polymerase uses free NTPs, complementary to the antisense strand of DNA to create an RNA copy of the DNA. # The mRNA leaves the nucleus - some modification may take place # Translation factors bind mRNA # Ribosome binds to mRNA # tRNA brings amino acids to ribosome # Ribosome begins translation at methionine start codon - matching anticodon on tRNA to triplet codons on mRNA to pair correct amino acid to the mRNA code # Ribosome stops translation at stop codon # Ribosome/mRNA/tripeptide complex will dissociate
Synthesis of a protein stops when?
it stops when an amino acid is missing from the diet
How does transcription end?
Transcription ends once the a termination sequence is reached. The sequence depends on which polymerase is being used and if the organism is a eukaryote or prokaryote. In Eukaryotes when RNA polymerase 1 is used the termination sequence is an 18 nucleotide long sequence. For RNA polymerase 3 the termination sequence is a short sequence of Uricils but the hairpin loop is not formed as it is in prokaryotes. For RNA polymerase 2 transcription is terminated and cleavage takes place 10-35 nucleotides downstream of the AAUAA sequence. For prokaryotes, termination can occur 2 ways. Termination can occur once the termination sequence is reached or using a protein called Rho factor. For termination without Rho factor, the termination sequence is short and rich in Guanines and Cytosines followed by many Uricils in a row. A-U bonds are weaker than G-C bonds, the string of U-A bonds are easily broken and release the RNA strand Using a Rho factor, once the Terminal sequence is reached, the Rho factor binds to a sequence 50-90 bases long and unwinds the DNA from the RNA , moving towards the 3' end, releasing the RNA
Describe the process of transcription in biology?
This process occurs in the nucleus of a cell. Firstly DNA helicase, will break the hydrogen bonds holding together the two strands of DNA. This exposes the bases on the two strands. RNA polymerase then anneals free nuleotides via phosphodiester bonds, via complementary base pairing to one strand of DNA, known as the template strand. Thus a strand of pre-messenger RNA is built, as the RNA polymerase moves along the DNA strand, the two DNA strands join up behind it. RNA polymerase stops the process of transcription when it reaches stop codons, which tell the enzyme to stop annealing nucleotides. The product is a length of pre-mRNA, which can then leave the nucleus throguh the nuclear pores and undergo splicing to remove introns and then translation.
What are the 6 steps of transcription?
1) RNA polymerase finds the promote or "start signal" along the DNA sequence. 2) RNA polymerase unwinds and upzips DNA 3) Then the enzyme adds complimentary RNA nucleotides to one DNA strand 4) This continues until a "top signal" is reached at the end of the gene on DNA 5) mRNA is released and leaves the nucleus 6) DNA zips together and twists
What tells the cell it is time to stop translating?
Stop codons in the mRNA
When does the polypeptide stop growing?
It reaches a stop codon on the mRNA molecule
Which process stop when rna polymerase comes to a terminator?
Transcription is the process that stops when RNA polymerase is terminated.
The correct sequence of the events of transcription is?
RNA polymerase reaches the beginning of a gene.
How could a substance that stops the synthesis of mRNA cause the liver to stop functioning?
A substance that stops the synthesis of mRNA causes the liver to stop functioning in various ways. This will hinder the making of new proteins and enzymes which facilitate the breakdown of various substances by the lover.
