chromatin

Examples of chromatin in the following topics:

• The Nucleus and Ribosomes

  • The nucleus stores chromatin (DNA plus proteins) in a gel-like substance called the nucleoplasm .
  • To understand chromatin, it is helpful to first consider chromosomes.
  • These protein-chromosome complexes are called chromatin .
  • The nucleolus is a condensed region of chromatin where ribosome synthesis occurs.
  • This image shows various levels of the organization of chromatin (DNA and protein).

• Eukaryotic Chromosomal Structure and Compaction

  • The DNA-histone complex is called chromatin.
  • The next level of compaction occurs as the nucleosomes and the linker DNA between them are coiled into a 30-nm chromatin fiber.
  • In the third level of packing, a variety of fibrous proteins is used to pack the chromatin.
  • The nucleosomes are coiled into a 30-nm chromatin fiber.

• Characteristics of Eukaryotic Cells

  • The nucleoplasm is the semi-solid fluid inside the nucleus where we find the chromatin and the nucleolus.
  • The nucleus stores chromatin (DNA plus proteins) in a gel-like substance called the nucleoplasm.The nucleolus is a condensed region of chromatin where ribosome synthesis occurs.The boundary of the nucleus is called the nuclear envelope.It consists of two phospholipid bilayers: an outer membrane and an inner membrane.The nuclear membrane is continuous with the endoplasmic reticulum.Nuclear pores allow substances to enter and exit the nucleus.

• Interphase

  • Throughout interphase, nuclear DNA remains in a semi-condensed chromatin configuration.

• Elongation and Termination in Eukaryotes

  • When eukaryotic cells are not dividing, their genes exist as a diffuse, but still extensively packaged and compacted mass of DNA and proteins called chromatin.
  • This is accomplished by a special protein dimer called FACT, which stands for "facilitates chromatin transcription."

• Programmed Cell Death

  • These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation.

• DNA and RNA

  • In eukaryotic cells, but not in prokaryotes, DNA forms a complex with histone proteins to form chromatin, the substance of eukaryotic chromosomes.

• The Mitotic Phase and the G0 Phase

  • During telophase, the "distance phase," the chromosomes reach the opposite poles and begin to decondense (unravel), relaxing into a chromatin configuration.