What is the difference between Monocistronic and Polycistronic?
The main difference between monocistronic and polycistronic mRNA is that the monocistronic mRNA produces a single protein while polycistronic mRNA produces several proteins that are functionally-related. Furthermore, eukaryotes have monocistronic mRNA while prokaryotes have polycistronic mRNA.
What is Polycistronic gene expression?
Polycistronic mRNA is a mRNA that encodes several proteins and is characteristic of many bacterial and chloroplast mRNAs. Polycistronic mRNAs consist of a leader sequence which precedes the first gene. Monocistronic mRNA is a mRNA that encodes only one protein and all eukaryotic mRNAs are monocistronic.
What is Polycistronic transcriptional unit?
The prokaryotic mRNAs are polycistronic which means that multiple genes are present on a single transcript and the single promoter initiates transcription of all those genes and regulates their expression. They have multiple initiation and termination codons and thus translate more than one protein.
What does Monocistronic mean?
Monocistronic is a term used in biochemistry to describe the capacity of eukaryotes to code one gene per one mRNA, as opposed to prokaryotes which can code many genes, sometimes all, on one mRNA, polycistronic.and Cistron is a term used alternatives to gene which is segment of DNA coding for polypeptide.
Are prokaryotes Monocistronic?
Prokaryotes produce both polycistronic and monocistronic mRNAs. Eukaryotes produce only monocistronic mRNAs.
What are exons?
An exon is the portion of a gene that codes for amino acids. In the cells of plants and animals, most gene sequences are broken up by one or more DNA sequences called introns.
What intron means?
Introns are noncoding sections of an RNA transcript, or the DNA encoding it, that are spliced out before the RNA molecule is translated into a protein. The sections of DNA (or RNA) that code for proteins are called exons.
What is the purpose of an intron?
Introns, from this perspective, have a profound purpose. They serve as hot spots for recombination in the formation of new combinations of exons. In other words, they are in our genes because they have been used during evolution as a faster pathway to assemble new genes.
What happens if introns are mutated?
Introns are supposed to be removed, while the exons are expressed. Mutations in these sequences may lead to retention of large segments of intronic DNA by the mRNA, or to entire exons being spliced out of the mRNA. These changes could result in production of a nonfunctional protein.
What are the three post transcriptional modifications?
The three post-transcriptional modifications are: 5′ capping, poly A tail addition, and splicing. Problem : What is the function of the 5′ cap in eukaryotes? The 5′ cap helps in eukaryotic mRNA recognition by ribosomes during translation.
What is a 3 base sequence on tRNA called?
anticodon – a sequence of three nucleotides on a tRNA molecule that bond to a complementary sequence on an mRNA molecule. The anticodon sequence determines the amino acid that the tRNA carries. codon– a sequence of three nucleotides on a mRNA molecule that encode a specific amino acid.