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What are three levels of structure in the DNA packaging system found within a eukaryotic nucleus?
Packing ratio - the length of DNA divided by the length into which it is packaged
For 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 chromosome
Nucleosome - 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
What else can I help you with?
Eukaryotic genes have more complicated ways to regulate gene transcription and expressiondescribe this and explain why its more complex than in prokaryotes?
The prime advantage of eukaryotic organisms is compartmentalization. By having compartments the eukaryotic organism can concentrate and refine specialized biochemical processes, improve overall capabilities and efficiencies and improve overall fitness.
What is a list of the 5 characteristics used to divide organism into kingdom?
the five kingdom classification system asks whether a cell is pro or eukaryotic, whether it is auto or heterotrophic, by structure and function, if it is produced in an embryo, and if it is unicellular or. multicellular
Characteristics of the series of levels surrounding the nucleus?
The series of levels surrounding the nucleus in an atom are referred to as electron shells. These shells represent different energy levels where electrons are located. As you move farther from the nucleus, the energy levels increase, allowing for more electrons to occupy them. The electrons in the outermost shell, known as the valence shell, play a key role in determining the chemical properties of the atom.
How do you describe the structure of an atom?
The current model of the atom shows that the atom is mainly empty space. There is a small part of the atom, called the nucleus, which contains most of the mass of the atom and all of its positive charges. Electrons orbit this nucleus in different energy levels.
What is the Basic structure of an atom?
Basically, an atom consists of a very tiny nucleus surrounded by electrons. To understand the basic structure of an atom, you really need to know that the nucleus and electrons have opposite electrical charges. The nucleus is positively charged, and the electrons are negatively charged. Opposite charges attract; this is why the electrons stay bound to the nucleus. If there are an equal number of negative (electron) charges as there are positive charges in the nucleus (which come from the protons in the nucleus), the atom will will have no charge. The nature of the electron states is addressed by quantum mechanics. Electrons have wave properties. Without getting too deeply into the quantum theory, quite a lot about atoms and their properties can be rationalized using the Bohr model of the atom.
What is the structure of an atom described as?
An atom consists of a nucleus containing protons and neutrons, surrounded by electrons in energy levels or shells. The protons and neutrons are located in the nucleus at the center of the atom, while the electrons orbit around the nucleus in specific energy levels.
What are the two main type of cells?
The two main types of cells are eukaryotic cells, which have a defined nucleus and organelles, and prokaryotic cells, which do not have a defined nucleus and organelles. Eukaryotic cells are found in plants, animals, fungi, and protists, while prokaryotic cells are found in bacteria and archaea.
Where are the nucleus and electron cloud found in a atomic structure?
The nucleus is found at the center of the atom and the electron cloud is found orbiting the nucleus at fixed, quantified radii.
Scientist who discovered structure of atom?
The structure of the atom was discovered by Ernest Rutherford and Niels Bohr. Rutherford's gold foil experiment led to the discovery of the nucleus, while Bohr proposed the planetary model of the atom with electrons orbiting the nucleus in specific energy levels.
The central part of an atom that contains protons and neutrons?
nucleus
What does the Newton atomic structure explain?
The Newton atomic structure explains the arrangement of particles in an atom, including the nucleus composed of protons and neutrons, and the electrons orbiting around the nucleus in fixed energy levels. This model helps us understand how atoms are structured and how they interact with each other in chemical reactions.
What is the Location of proton and neutrons?
Electrons -- in energy levels outside the nucleus. Protons in the nucleus. Neutrons in the nucleus.
Where are energy levels located in an atom, and how are they related to the distance from the nucleus?
Energy levels in an atom are located at specific distances from the nucleus. These energy levels are related to the distance from the nucleus in that the farther away an energy level is, the higher the energy of the electrons in that level.
Are energy levels in a hydrogen atom further apart near the nucleus?
No, the energy levels in a hydrogen atom are closer together near the nucleus and become more widely spaced as you move further away. The energy of an electron in a hydrogen atom is determined by its distance from the nucleus, with lower energy levels closer to the nucleus and higher energy levels further away.
What does a atom of argon look like?
An atom of argon consists of a nucleus composed of 18 protons and usually 22 neutrons surrounded by 18 electrons in energy levels. The nucleus is very small compared to the electron cloud, which extends far out around the nucleus. The overall structure is spherical and symmetrical due to the arrangement of the electrons in their respective energy levels.
Where do we find electrons?
Electrons are found in the electron cloud surrounding the nucleus of an atom. They move rapidly within this region, occupying various energy levels based on the atom's structure.
What is the structure of an atom of germanium?
A germanium atom consists of a nucleus made up of protons and neutrons, surrounded by electron shells. It has 32 protons and typically 32 neutrons in its nucleus, which gives it an atomic number of 32. The electrons are arranged in energy levels around the nucleus, following the electron configuration rules.
