The DNA molecules are condensed 50 times than its normal structure in the chromatin fibres. Chromosome appears only in the metaphase of the cell cycle, achieving its highest condensed structure. The main purpose of the chromosome is to ensure the separation of doubled genetic material between the two daughter cells.
DNA in the nucleus is organized in highly condensed, tightly packaged structures called chromosomes
This relative resistance to nuclease indicates that the chromatin structure of nonexpressed DNA is more condensed than that of transcribed DNA. In condensed chromatin, the DNA is largely inaccessible to DNase I because of its close association with histones and possibly other less-abundant chromatin proteins.
Chapter 17 HW. Acetylation of histone tails is a reversible process. DNA is not transcribed when chromatin is packaged tightly in a condensed form. Acetylation of histone tails in chromatin allows access to DNA for transcription. Methylation of histone tails in chromatin can promote condensation of the chromatin.
Linker histones such as H1 and its isoforms are involved in chromatin compaction and sit at the base of the nucleosome near the DNA entry and exit binding to the linker region of the DNA. Non-condensed nucleosomes without the linker histone resemble "beads on a string of DNA" under an electron microscope.
DNA packaging. Each chromosome consists of one continuous thread-like molecule of DNA coiled tightly around proteins, and contains a portion of the 6,400,000,000 basepairs (DNA building blocks) that make up your DNA. The way DNA is packaged into chromatin is a factor in how protein production is controlled.
In addition to the condensed genome, numbers of phage capsids contain a diversity of internal proteins, despite, as mentioned above, their DNA retaining conserved features, including a density of ~500 mg/ml and displaying the characteristic 2.5-nm duplex-to-duplex spacing. These proteins vary in length, copy number, function,...
the nucleus is the structure which contains DNA. the DNA is wound into a tight double helix and kept in the nucleus where it undergoes replication. The nucleus functions in a capacity similar to a ...
The rod shaped structures in the nucleus of a cell are chromosomes. They carry genetic material in a "rod" of DNA that is bonded to various proteins in the cell nucleus. The word "chromosome" is derived from the Greek words "chroma," meaning "color," and "soma," meaning "body."
During mitosis, the chromosomes are said to be condensed, meaning the DNA is tightly packed by proteins into thick structures. In humans, condensed chromosomes look like thick Xs. Before mitosis begins, the cell has already made new copies of each of its chromosomes. However, these new copies remain attached to the original chromosome.
Chromatin fibers are packaged by proteins into a condensed structure called chromatin. Chromatin contains the vast majority of DNA and a small amount inherited maternally, can be found in the mitochondria .
Chromatin is a complex of macromolecules found in cells, consisting of DNA, protein, and RNA. The primary functions of chromatin are 1) to package DNA into a more compact, denser shape, 2) to reinforce the DNA macromolecule to allow mitosis, 3) to prevent DNA damage, and 4) to control gene expression and DNA replication.
Heterochromatin is difficult to analyze because of its condensed state and repetitive DNA sequence. However, euchromatin poses fewer challenges as it contains active genes and maintains an open and extended structure. Chromatin immunoprecipitation (ChIP) is the technique of choice to study chromatin modifications.
To fit into this compartment the DNA has to be condensed in some manner. Packing ratio is used to describe the degree to which DNA is condensed. To achieve the overall packing ratio, DNA is not packaged directly into structure of chromatin. Instead, it contains several hierarchies of organization.
What Is a Structure Containing Condensed DNA? Structure Containing Condensed Dna Structure Responsible for Protein Synthesis Carries out Specific Activities in a Cell Protrudes from Cell's Surface and Enables Movement Interior of Cell Double Layer of Phospholipids A Chloroplast is One
The bacterial cell contains a DNA that is huge compared to that present in viruses. The DNA of E. coli appears to consist of a single, enormous double-stranded DNA molecule with a molecular weight of about 2.8 x 10 9, a thickness of about 2.0 nm and a contour length of about 1,360µm. E. coli DNA contains 4 million deoxyribonucleotide pairs.
Eukaryotic Chromosome Structure The length of DNA in the nucleus is far greater than the size of the compartment in which it is contained. To fit into this compartment the DNA has to be condensed in some manner.
When fully condensed, replicated chromosomes appear as thick X-shaped structures that are readily observed under the microscope (see figure below). Chromosomes can have 1 or 2 chromatids, depending on whether they have replicated. CHROMOSOMAL STRUCTURE. A chromatid is a condensed DNA subunit of a chromosome. The two chromatids of a duplicated chromosome are held together at a region of DNA called the centromere (see figure below).
DNA condensation in eukaryotes. Most of the time, between cell divisions, chromatin is optimized to allow easy access of transcription factors to active genes, which are characterized by a less compact structure called euchromatin, and to alleviate protein access in more tightly packed regions called heterochromatin.
The complexes between eukaryotic DNA and proteins are called chromatin, which typically contains about twice as much protein as DNA. The major proteins of chromatin are the histones —small proteins containing a high proportion of basic amino acids (arginine and lysine) that facilitate binding to the negatively charged DNA molecule.
-Changes in nucleosome structure allow access to DNA -Interphase chromosomes contain both condensed and more extended forms of chromatin *A cell can regulate its chromosomes structure, by temporarily condensing or decondensing particular regions of its chromosomes, using: ~Chromatin-remodeling complexes ~Enzymes that covalently modify histone tails
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