nucleosome
Packing ratio - the length of DNA divided by the length into which it is packagedFor example, the shortest human chromosome contains 4.6 x 107 bp of DNA (about 10 times the genome size of E. coli). This is equivalent to 14,000 µm of extended DNA. In its most condensed state during mitosis, the chromosome is about 2 µm long. This gives a packing ratio of 7000 (14,000/2).To achieve the overall packing ratio, DNA is not packaged directly into final structure of chromatin. Instead, it contains several hierarchies of organization. The first level of packing is achieved by the winding of DNA around a protein core to produce a "bead-like" structure called a nucleosome. This gives a packing ratio of about 6. This structure is invariant in both the euchromatin and heterochromatin of all chromosomes. The second level of packing is the coiling of beads in a helical structure called the 30 nm fiber that is found in both interphase chromatin and mitotic chromosomes. This structure increases the packing ratio to about 40. The final packaging occurs when the fiber is organized in loops, scaffolds and domains that give a final packing ratio of about 1000 in interphase chromosomes and about 10,000 in mitotic chromosomes.Eukaryotic chromosomes consist of a DNA-protein complex that is organized in a compact manner which permits the large amount of DNA to be stored in the nucleus of the cell. The subunit designation of the chromosome is chromatin. The fundamental unit of chromatin is the nucleosome.Chromatin - the unit of analysis of the chromosome; chromatin reflects the general structure of the chromosome but is not unique to any particular chromosomeNucleosome - simplest packaging structure of DNA that is found in all eukaryotic chromosomes; DNA is wrapped around an octamer of small basic proteins called histones; 146 bp is wrapped around the core and the remaining bases link to the next nucleosome; this structure causes negative supercoiling
Parasites can be prokaryotic or eukaryotic. Prokaryotic parasites include bacteria that cause infections like Salmonella and E. coli. Eukaryotic parasites include protozoa such as Plasmodium (which causes malaria) and helminths like tapeworms.
The first level of control of eukaryotic gene transcription is at the initiation stage, where transcription factors bind to specific DNA sequences in the promoter region of a gene to recruit RNA polymerase and initiate transcription. This process is regulated by various factors including activators, repressors, and chromatin modifiers that influence the accessibility of the DNA to the transcription machinery.
chaos
The beads on a string level of DNA packing refer to nucleosomes, which are composed of DNA wrapped around histone proteins. These nucleosomes form the basic unit of chromatin structure, helping to compact and organize the DNA within the cell nucleus.
Packing ratio - the length of DNA divided by the length into which it is packagedFor example, the shortest human chromosome contains 4.6 x 107 bp of DNA (about 10 times the genome size of E. coli). This is equivalent to 14,000 µm of extended DNA. In its most condensed state during mitosis, the chromosome is about 2 µm long. This gives a packing ratio of 7000 (14,000/2).To achieve the overall packing ratio, DNA is not packaged directly into final structure of chromatin. Instead, it contains several hierarchies of organization. The first level of packing is achieved by the winding of DNA around a protein core to produce a "bead-like" structure called a nucleosome. This gives a packing ratio of about 6. This structure is invariant in both the euchromatin and heterochromatin of all chromosomes. The second level of packing is the coiling of beads in a helical structure called the 30 nm fiber that is found in both interphase chromatin and mitotic chromosomes. This structure increases the packing ratio to about 40. The final packaging occurs when the fiber is organized in loops, scaffolds and domains that give a final packing ratio of about 1000 in interphase chromosomes and about 10,000 in mitotic chromosomes.Eukaryotic chromosomes consist of a DNA-protein complex that is organized in a compact manner which permits the large amount of DNA to be stored in the nucleus of the cell. The subunit designation of the chromosome is chromatin. The fundamental unit of chromatin is the nucleosome.Chromatin - the unit of analysis of the chromosome; chromatin reflects the general structure of the chromosome but is not unique to any particular chromosomeNucleosome - simplest packaging structure of DNA that is found in all eukaryotic chromosomes; DNA is wrapped around an octamer of small basic proteins called histones; 146 bp is wrapped around the core and the remaining bases link to the next nucleosome; this structure causes negative supercoiling
Parasites can be prokaryotic or eukaryotic. Prokaryotic parasites include bacteria that cause infections like Salmonella and E. coli. Eukaryotic parasites include protozoa such as Plasmodium (which causes malaria) and helminths like tapeworms.
The first level of control of eukaryotic gene transcription is at the initiation stage, where transcription factors bind to specific DNA sequences in the promoter region of a gene to recruit RNA polymerase and initiate transcription. This process is regulated by various factors including activators, repressors, and chromatin modifiers that influence the accessibility of the DNA to the transcription machinery.
Eukaryotic DNA has histone proteins and a level of organization that prokaryotic DNA lacks.
Packing Group I (PG I) is the greatest danger; Packing Group III (PG III) is the least.
substrate level phosphorylation
The simplest level at which life may exist is in a cell.
The simplest level at which life may exist is in a cell.
The simplest level at which life may exist is in a cell.
Cells are the simplest organizational level of the human body.
chaos
No, acetone is not classified as Packing Group I (PG I). It is classified as Packing Group II (PG II) under the United Nations classification system for hazardous materials, which indicates it has a moderate level of danger. Acetone is flammable and should be handled with care, but it is not considered as dangerous as substances in Packing Group I.