File Name: difference between prokaryotic and eukaryotic transcription .zip
- The Difference Between Prokaryotic and Eukaryotic Gene Expression
- Eukaryotic transcription
- 16.2B: Prokaryotic versus Eukaryotic Gene Expression
The Difference Between Prokaryotic and Eukaryotic Gene Expression
Prokaryotes regulate gene expression by controlling the amount of transcription, whereas eukaryotic control is much more complex. To understand how gene expression is regulated, we must first understand how a gene codes for a functional protein in a cell. The process occurs in both prokaryotic and eukaryotic cells, just in slightly different manners.
Prokaryotic organisms are single-celled organisms that lack a defined nucleus; therefore, their DNA floats freely within the cell cytoplasm. When the resulting protein is no longer needed, transcription stops. Thus, the regulation of transcription is the primary method to control what type of protein and how much of each protein is expressed in a prokaryotic cell.
All of the subsequent steps occur automatically. When more protein is required, more transcription occurs. Therefore, in prokaryotic cells, the control of gene expression is mostly at the transcriptional level. Eukaryotic cells, in contrast, have intracellular organelles that add to their complexity.
The newly-synthesized RNA is then transported out of the nucleus into the cytoplasm where ribosomes translate the RNA into protein. The processes of transcription and translation are physically separated by the nuclear membrane; transcription occurs only within the nucleus, and translation occurs only outside the nucleus within the cytoplasm. The regulation of gene expression can occur at all stages of the process. Regulation may occur when the DNA is uncoiled and loosened from nucleosomes to bind transcription factors epigenetics , when the RNA is transcribed transcriptional level , when the RNA is processed and exported to the cytoplasm after it is transcribed post-transcriptional level , when the RNA is translated into protein translational level , or after the protein has been made post-translational level.
Learning Objectives Compare and contrast prokaryotic and eukaryotic gene expression. Key Points Prokaryotic gene expression is primarily controlled at the level of transcription. Eukaryotic gene expression is controlled at the levels of epigenetics, transcription, post-transcription, translation, and post-translation. 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. Key Terms epigenetics : the study of heritable changes caused by the activation and deactivation of genes without any change in DNA sequence nucleosome : any of the subunits that repeat in chromatin; a coil of DNA surrounding a histone core. Prokaryotic versus Eukaryotic Gene Expression To understand how gene expression is regulated, we must first understand how a gene codes for a functional protein in a cell.
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. Further regulation may occur through post-translational modifications of proteins. Provided by : Boundless. October 16, Provided by : Wiktionary. Located at : en.
Since prokaryotic cells typically have only a single, circular chromosome, they can replicate faster than eukaryotic cells. In fact, a prokaryotic cell can undergo two rounds of DNA replication before the cell, itself, has divided. This means that DNA replication can occur during cell division in prokaryotes. Since eukaryotic cells typically have multiple linear chromosomes, capped with telomeres, eukaryotic DNA replication and cell division mitosis and meiosis are a bit more complicated. In addition, the telomeres—repeating DNA sequences at the ends of each chromosome—limit the number of times a cell can divide before it dies or becomes senescent. Each time a typical or somatic eukaryotic cell divides, the telomeres get shorter. The key difference between prokaryotic and eukaryotic cells is that eukaryotic cells have a membrane-bound nucleus and membrane-bound organelles , whereas prokaryotic cells lack a nucleus.
While a few specific aspects of transcription differ between eukaryotes and prokaryotes, the basic chemistry behind the process is the same. Both.
16.2B: Prokaryotic versus Eukaryotic Gene Expression
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Let us make an in-depth study of transcription synthesis of RNA in prokaryotes and eukaryotes. In prokaryotic organisms transcription occurs in three phases known as initiation, elongation and termination. This form is called the holoenzyme.
Prokaryotic and Eukaryotic Gene Regulation
Eukaryotic transcription is the elaborate process that eukaryotic cells use to copy genetic information stored in DNA into units of transportable complementary RNA replica. Unlike prokaryotic RNA polymerase that initiates the transcription of all different types of RNA, RNA polymerase in eukaryotes including humans comes in three variations, each translating a different type of gene. A eukaryotic cell has a nucleus that separates the processes of transcription and translation. Eukaryotic transcription occurs within the nucleus where DNA is packaged into nucleosomes and higher order chromatin structures. The complexity of the eukaryotic genome necessitates a great variety and complexity of gene expression control. Eukaryotic transcription proceeds in three sequential stages: initiation, elongation, and termination.