eukaryotic

Examples of eukaryotic in the following topics:

• Characteristics of Eukaryotic DNA

  • Prokaryotic cells are known to be much less complex than eukaryotic cells since eukaryotic cells are considered to be present at a later point of evolution.
  • It is probable that eukaryotic cells evolved from prokaryotic cells.
  • All extant eukaryotes have cells with nuclei; most of a eukaryotic cell's genetic material is contained within the nucleus.
  • All extant eukaryotes have these cytoskeletal elements.
  • A major DNA difference between eukaryotes and prokaryotes is the presence of mitochondrial DNA (mtDNA) in eukaryotes.

• Prokaryotic versus Eukaryotic Gene Expression

  • Prokaryotes regulate gene expression by controlling the amount of transcription, whereas eukaryotic control is much more complex.
  • The process occurs in both prokaryotic and eukaryotic cells, just in slightly different manners.
  • Eukaryotic cells, in contrast, have intracellular organelles that add to their complexity.
  • In eukaryotic cells, the DNA is contained inside the cell's nucleus where it is transcribed into RNA.
  • 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.

• Endosymbiosis and the Evolution of Eukaryotes

  • Eukaryotes may have been a product of one cell engulfing another and evolving over time until the separate cells became a single organism.
  • To fully understand eukaryotic organisms, it is necessary to understand that all extant eukaryotes are descendants of a chimeric organism that was a composite of a host cell and the cell(s) of an alpha-proteobacterium that "took up residence" inside the host.
  • Endosymbiotic events probably contributed to the origin of the last common ancestor (LCA) of today's eukaryotes.
  • In 1981 she argued that eukaryotic cells originated as communities of interacting entities, including endosymbiotic spirochetes that developed into eukaryotic flagella and cilia.
  • Describe the general concept of endosymbiosis and the evolution of eukaryotes

• Endosymbiotic Theory and the Evolution of Eukaryotes

  • There are several other competing hypotheses as to the origin of eukaryotes and the nucleus.
  • If the eukaryotic nucleus evolved this way, we would expect one of the two types of prokaryotes to be more closely-related to eukaryotes.
  • Most interestingly, the eukaryote-first hypothesis proposes prokaryotes actually evolved from eukaryotes by losing genes and complexity .
  • Three alternate hypotheses of eukaryotic and prokaryotic evolution are (a) the nucleus-first hypothesis, (b) the mitochondrion-first hypothesis, and (c) the eukaryote-first hypothesis.
  • Describe the genome fusion hypothesis and its relationship to the evolution of eukaryotes

• Initiation of Transcription in Eukaryotes

  • Initiation is the first step of eukaryotic transcription and requires RNAP and several transcription factors to proceed.
  • The features of eukaryotic mRNA synthesis are markedly more complex those of prokaryotes.
  • Each eukaryotic polymerase also requires a distinct set of transcription factors to bring it to the DNA template.
  • Eukaryotic pre-mRNAs undergo extensive processing after transcription, but before translation.
  • This interactive models the process of DNA transcription in a eukaryotic cell.

• DNA Packaging

  • A eukaryote contains a well-defined nucleus, whereas in prokaryotes the chromosome lies in the cytoplasm in an area called the nucleoid.
  • In eukaryotic cells, DNA and RNA synthesis occur in a separate compartment from protein synthesis.
  • Eukaryotes, whose chromosomes each consist of a linear DNA molecule, employ a different type of packing strategy to fit their DNA inside the nucleus.
  • In interphase, eukaryotic chromosomes have two distinct regions that can be distinguished by staining.
  • A eukaryote contains a well-defined nucleus, whereas in prokaryotes, the chromosome lies in the cytoplasm in an area called the nucleoid.

• Characteristics of Eukaryotic Cells

  • Like a prokaryotic cell, a eukaryotic cell has a plasma membrane, cytoplasm, and ribosomes.
  • However, unlike prokaryotic cells, eukaryotic cells have:
  • Eukaryotic cells have a true nucleus, which means the cell's DNA is surrounded by a membrane.
  • In eukaryotes, chromosomes are linear structures.
  • All of these organelles are found in each and every eukaryotic cell.

• Early Eukaryotes

  • Protists are eukaryotes that first appeared approximately 2 billion years ago with the rise of atmospheric oxygen levels.
  • They are among the first organisms to evolve with the rise of eukaryotes.
  • The oldest fossil evidence of eukaryotes, cells measuring 10 µm or greater, is about 2 billion years old.
  • It is probable that today's eukaryotes are descended from an ancestor that had a prokaryotic cellular organization.
  • Discuss the origins of eukaryotes in terms of the geologic time line

• Use of Whole-Genome Sequences of Model Organisms

  • Sequencing genomes of model organisms allows scientists to study homologous proteins in more complex eukaryotes, such as humans.
  • Eukaryotes are organisms containing cells that enclose complex organelles within a well-defined cell membrane.
  • The defining characteristic that sets eukaryotes and prokaryotes apart is the eukaryotes' nucleus, or nuclear envelope, in which an organism's genetic information is contained.
  • The first eukaryotic genome to be sequenced was that of S. cerevisiae, which is the yeast used in baking and brewing.
  • It is the most-studied eukaryotic model organism in molecular and cell biology, similar to E. coli's role in the study of prokaryotic organisms.

• Binary Fission

  • In both prokaryotic and eukaryotic cells, the outcome of cell reproduction is a pair of daughter cells that are genetically identical to the parent cell.
  • Due to the relative simplicity of the prokaryotes, the cell division process, or binary fission, is a less complicated and much more rapid process than cell division in eukaryotes.
  • The packing proteins of bacteria are, however, related to the cohesin and condensin proteins involved in the chromosome compaction of eukaryotes.
  • The precise timing and formation of the mitotic spindle is critical to the success of eukaryotic cell division.
  • A survey of mitotic assembly components found in present-day unicellular eukaryotes reveals crucial intermediary steps to the complex membrane-enclosed genomes of multicellular eukaryotes.