16.1 Regulation of Gene Expression

16.1 Regulation of Gene Expression

  • The proper time and place for the synthesis of necessary proteins is important for a cell to function properly.
    • The cells control or regulate the synthesis of their genes.
    • Each cell controls when and how its genes are expressed in a complex multi-cellular organisms.
    • There must be internal chemical mechanisms that control when a gene is expressed, how much of it is made, and when it's time to stop making it because it's no longer needed.
  • The regulation of genes conserves space and energy.
    • It would take a lot of energy to express all the genes at the same time, so it's more efficient to turn on the genes when they're needed.
    • Only expressing a subset of genes in each cell saves space because DNA must be unwound from its tightly coiled structure to translate it.
    • Cells would have to be huge if every cell had a certain amount of a certain molecule in it.
  • Malfunctions in the control of gene expression can lead to the development of many diseases, including cancer.
  • Understanding how a gene codes for a function in a cell is the first step to understanding how gene expression is regulated.
    • The process occurs in both prokaryotic and eukaryotic cells.
  • Single-celled organisms that lack a cell nucleus have their DNA float freely in the cell cytoplasm.
    • The processes of transcription and translation occur at the same time.
    • The transcription stops when there is no need for it.
    • The regulation of DNA transcription is the primary method of controlling what type of protein and how much of it is expressed in a prokaryotic cell.
    • The next steps occur automatically.
    • More transcription occurs when moreProtein is required.
    • The control of gene expression in prokaryotic cells is mostly at the transcriptional level.
  • Eukaryotic cells have more to do with their complexity.
    • The nucleus of a cell is where the DNA is contained.
    • ribosomes translate the newly synthesisedRNA into theProtein is then transported out of the nucleus into the cytoplasm.
    • The processes of translation and transcription are separated from one another by the nuclear membranes.
    • Gene expression can be regulated at all stages of the process.

  • Both prokaryotic transcription and translation occur in the same place.
    • Eukaryotic genes are expressed in the nucleus and in the cytoplasm.
    • Posttranslational modifications of proteins may lead to further regulation.
  • There are differences in the regulation of gene expression between prokaryotes and eukaryotes.
    • In subsequent modules, the regulation of gene expression is discussed.
  • Contain nucleus DNA is found in the nucleus, but it is confined to the nuclear compartment, and it takes place 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- There is a process of translation in the cytoplasm.
  • Control of the amount of transcription is what prokaryotic cells can do.
    • The control of gene expression became more complex as the cells evolved.
    • The evolution of eukaryotic cells brought about the separation of important cellular components and processes.
    • There is a nuclear region with the DNA.
    • There were two different cellular compartments for transcription and translation.
    • It was possible to control the expression of genes by regulating the transcription in the nucleus and also by controlling the translation of genes outside the nucleus.
  • Gene regulation is done to conserve cell resources.
    • Other regulatory processes may be defensive.
    • There are cellular processes that protect the cell from infections.
    • If the cell could shut off its genes for a short period of time, it would be able to survive an attack.