Prokaryotes commonly use attenuation as a mechanism to control gene expression, but eukaryotes do not. … In prokaryotes transcription and translation are coupled. This makes attenuation possible.
Why are eukaryotes not regulated by attenuation?
(In eukaryotes, there is no exact equivalent of attenuation, because transcription occurs in the nucleus and translation occurs in the cytoplasm, making this sort of coordinated effect impossible.) Yet another layer of prokaryotic regulation affects the structure of RNA polymerase, which turns on large groups of genes.
Could transcription attenuation be used to regulate genes in eukaryotes?
The expression of eukaryotic genes is controlled primarily at the level of initiation of transcription, although in some cases transcription may be attenuated and regulated at subsequent steps.
Why does transcriptional attenuation occur only in prokaryotes?
Attenuation. … Attenuation is possible because the genetic material of prokaryotes in in the cell’s cytoplasm with its ribosomes. In prokaryotes, it is possible for ribosomes to begin translating the mRNA while RNA polymerase is still transcribing the DNA sequence, allowing translation to have an effect on transcription.What is attenuation in biology?
Attenuation is a regulatory mechanism used in bacterial operons to ensure proper transcription and translation. In bacteria, transcription and translation are capable of proceeding simultaneously. … The process of attenuation involves the presence of a stop signal that indicates premature termination.
How does attenuation regulate gene expression?
Like regulation by the trp repressor, attenuation is a mechanism for reducing expression of the trp operon when levels of tryptophan are high. However, rather than blocking initiation of transcription, attenuation prevents completion of transcription.
How do eukaryotic organisms regulate the process of translation?
Eukaryotic organisms express a subset of the DNA that is encoded in any given cell. In each cell type, the type and amount of protein is regulated by controlling gene expression. To express a protein, the DNA is first transcribed into RNA, which is then translated into proteins.
Why can eukaryotes transcription and translation at the same time?
Prokaryotic transcription and translation can occur simultaneously. This is impossible in eukaryotes, where transcription occurs in a membrane-bound nucleus while translation occurs outside the nucleus in the cytoplasm. … Many of these transcription factors are homodimers containing helix-turn-helix DNA-binding motifs.Why is attenuation possible for prokaryotes and not eukaryotes?
Attenuation is made possible by the fact that in prokaryotes (which have no nucleus), the ribosomes begin translating the mRNA while RNA polymerase is still transcribing the DNA sequence. This allows the process of translation to directly affect transcription of the operon.
Why is transcription and translation coupled in prokaryotes but not in eukaryotes?In eukaryotic m-RNA has to be processed (splicing) before it become active. Since RNA is synthesised inside the nucleus and translation occurs in the cytoplasm, coupling of transcription and translation is not possible.
Article first time published onWhy is transcription more complex in eukaryotes?
Eukaryotic transcription is more complex than prokaryotic transcription. For instance, in eukaryotes the genetic material (DNA), and therefore transcription, is primarily localized to the nucleus, where it is separated from the cytoplasm (in which translation occurs) by the nuclear membrane.
How does regulation of transcription in eukaryotes differ from regulation of transcription in prokaryotes?
Therefore, in prokaryotic cells, the control of gene expression is mostly at the transcriptional level. … Eukaryotic gene expression is regulated during transcription and RNA processing, which take place in the nucleus, and during protein translation, which takes place in the cytoplasm.
How do transcription factors regulate gene expression in eukaryotes?
Transcription factors are proteins that regulate the transcription of genes—that is, their copying into RNA, on the way to making a protein. … Transcription factors help ensure that the right genes are expressed in the right cells of the body, at the right time.
How does attenuation occur?
Attenuation occurs on computer networks because of: Range – over longer distances both wired and wireless transmissions gradually dissipate in strength. Interference – radio interference or physical obstructions, such as walls, dampen communication signals on wireless networks.
Which of the following bacterial operon is not controlled by attenuation?
2. Which of the following bacterial operon is not controlled by attenuation? Explanation: Arabinose is a carbohydrate. 3.
How does attenuation control tryptophan operon?
When tryptophan is low, RNA polymerase (blue) reads through the attenuator and genes are transcribed. Attenuation of the trp operon of E. coli. When tryptophan is high, the attenuator causes premature termination of transcription, so the genes that produce more tryptophan are not transcribed.
What is the main difference between eukaryotic and prokaryotic gene regulation?
Prokaryotic gene expression (both transcription and translation) occurs within the cytoplasm of a cell due to the lack of a defined nucleus; thus, the DNA is freely located within the cytoplasm. Eukaryotic gene expression occurs in both the nucleus (transcription) and cytoplasm (translation).
Why do eukaryotes have a more complex system of gene regulation than prokaryotes?
Eukaryotic gene expression is more complex than prokaryotic gene expression because the processes of transcription and translation are physically separated. Unlike prokaryotic cells, eukaryotic cells can regulate gene expression at many different levels.
When can gene regulation occur in eukaryotes?
Gene regulation can occur at any point of the transcription-translation process but most often occurs at the transcription level. Proteins that can be activated by other cells and signals from the environment are called transcription factors.
How are genes coordinately controlled in eukaryotic cells?
Coordinately controlled genes in eukaryotic cells share a set of control elements. Coordinately controlled genes in eukaryotic cells are located together on the same chromosome. Coordinately controlled genes in eukaryotic cells are activated by the same chemical signals.
How attenuation regulates protein synthesis in prokaryotic cells?
Attenuation occurs by a mechanism by which rapid translation of the nascent transcript causes the termination of transcription. As the transcript is being produced, if ribosomes attach and rapidly translate the transcript, a secondary structure is generated in the mRNA that is a termination signal for RNA polymerase.
What are the limitations of using QRT PCR to study gene expression?
The main disadvantage of this method is that it requires separate priming reactions for each target; hence it is not possible to return to the same preparation and amplify other targets at a later stage. It is also wasteful if only limited amounts of RNA are available.
What is the mechanism of transcription attenuation?
Transcriptional attenuation is a regulatory mechanism that causes premature termination of transcription under certain conditions, thereby preventing the expression of the mRNA required for expression of the corresponding gene products.
How is the process of transcription and translation different in eukaryotes and bacteria?
Bacteria have an interesting answer. In bacteria, mRNA is translated into protein as soon as it is transcribed. … Thus, in eukaryotes, while transcription occurs in the nucleus, translation occurs in the cytoplasm. In other words, eukaryotic transcription and translation are spatially and temporally isolated.
Why can translation begin before transcription is complete in prokaryotes but not in eukaryotes?
Why can translation begin before transcription is complete in prokaryotes but not in eukaryotes? … Because mRNA is produced in the cytoplasm in prokaryotes, the start codons of an mRNA being transcribed are available to ribosomes before the entire mRNA molecule is even made.
Why can't eukaryotes transcribe and translate efficiently?
Prokaryotic transcription occurs in the cytoplasm alongside translation. Prokaryotic transcription and translation can occur simultaneously. This is impossible in eukaryotes, where transcription occurs in a membrane-bound nucleus while translation occurs outside the nucleus in the cytoplasm.
Which processes occur in eukaryotes and prokaryotes?
Prokaryotes and eukaryotes are both capable of the main processes of the central dogma: DNA replication, transcription, and translation. For this to be possible, prokaryotes must contain DNA, transcription proteins, RNA, and ribosomes.
How does transcription and RNA processing in eukaryotes differ from the same processes in prokaryotes?
Eukaryotes have three types of RNA polymerases, I, II, and III, and prokaryotes only have one type. … Another main difference between the two is that transcription and translation occurs simultaneously in prokaryotes and in eukaryotes the RNA is first transcribed in the nucleus and then translated in the cytoplasm.
When and where are eukaryotic transcripts modified?
This transcript must undergo processing (splicing and addition of 5′ cap and poly-A tail) while it is still in the nucleus in order to become a mature mRNA. The mature mRNA is exported from the nucleus to the cytosol, where it is translated at a ribosome to make a polypeptide.
Where does protein synthesis occur in eukaryotes?
For instance, protein synthesis in prokaryotes occurs in the cytoplasm. In eukaryotes, the first step (transcription) occurs in the nucleus. When the transcript (mRNA) is formed, it proceeds to the cytoplasm where ribosomes are located.
Which of the following occurs in prokaryotes but not in eukaryotes?
Which of the following occurs in prokaryotes but not in eukaryotes? Concurrent transcription and translation. The flow of information in a cell proceeds in what sequence?
