What do you mean by chromatin?

Chromatin is a complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells. Nuclear DNA does not appear in free linear strands; it is highly condensed and wrapped around nuclear proteins in order to fit inside the nucleus.

What is meant by chromatin remodeling?

Chromatin remodeling is the rearrangement of chromatin from a condensed state to a transcriptionally accessible state, allowing transcription factors or other DNA binding proteins to access DNA and control gene expression.

Where does chromatin remodeling occur?

In eukaryotes, DNA is tightly wound into a complex called chromatin. Thanks to the process of chromatin remodeling, this complex can be “opened” so that specific genes are expressed.

How do chromatin remodeling complexes work?

Chromatin remodeling complexes can be broadly categorized into those that carry out remodeling by utilizing energy from ATP hydrolysis and those that covalently modify chromatin proteins and thus bring about permanent yet reversible alteration in the chromatin structure.

What causes chromatin remodeling?

Such remodeling is principally carried out by 1) covalent histone modifications by specific enzymes, e.g., histone acetyltransferases (HATs), deacetylases, methyltransferases, and kinases, and 2) ATP-dependent chromatin remodeling complexes which either move, eject or restructure nucleosomes.

What is chromatin remodeling quizlet?

chromatin remodeling. he dynamic modification of chromatin architecture to allow access of condensed genomic DNA to the regulatory transcription machinery proteins, and thereby control gene expression.

What is chromatin function?

Chromatin fibers are coiled and condensed to form chromosomes. Chromatin makes it possible for a number of cell processes to occur including DNA replication, transcription, DNA repair, genetic recombination, and cell division.

Why is chromatin important?

Chromatin organization is crucial for genome replication, transcriptional silencing, and DNA repair and recombination. The replication machinery is relevant for the maintenance of chromatin states, influencing DNA replication origin specification and accessibility.

How do chromatin remodeling complexes recognize the genes?

The many different remodeling enzymes recognize different histone modifications, DNA structures/sequences and RNA signals that target them to specific genomic loci. To recognize these chromatin signals remodeling complexes have dedicated protein domains, termed reader domains.

How transcription is affected by chromatin remodeling?

As chromatin is condensed into the primary nucleosome structure, DNA becomes less accessible for transcription factors. With the loosening of this chromatin structure, however, transcription machinery is better able to access the genomic DNA, and transcription is thus promoted.

What is the mechanism of action of a chromatin remodeling complex quizlet?

Chromatin-remodeling complexes are targeted to specific DNA sequences by transcriptional activators or repressors that attach to a remodeling complex and then bind to the promoters of specific genes.

What role do chromatin remodelers play in eukaryotic gene expression?

What role do chromatin remodelers play in eukaryotic gene expression? Chromatin remodeler enzymes can enzymatically change the distribution or composition of nucleosomes (histone octamers). a eukaryotic cis-acting DNA regulatory sequence to which transacting factors bind and stimulate transcription.

What part of the chromatin fiber does the remodeling complex attach to quizlet?

book: (A) Using the energy of ATP hydrolysis, the remodeling complex is thought to push on the DNA of its bound nucleosome and loosen its attachment to the nucleosome core.

What happens to histone during replication?

During DNA replication, histone arrangement is perturbed, first to allow progression of DNA polymerase and then during repackaging of the replicated DNA.

What happens to nucleosomes during DNA replication?

During DNA replication, nucleosomes ahead of the replication fork must be disassembled to facilitate the movement of the DNA replication machinery, and behind the fork, new nucleosomes must be reformed on daughter strands with both recycled parental histones and newly synthesized histones to restore the chromatin state …

What is an example of a chromatin?

Chromatin is a substance made up of DNA or RNA and proteins, such as histones. It condenses during cell division (mitosis or meiosis) and becomes a chromosome. Chromatins are “unwound” condensed structures whereas chromosomes are highly packaged and more condensed than chromatins.

What are the two types of chromatin?

There are two chromatin types: euchromatin and heterochromatin. The euchromatin form is less dense, while the heterochromatin form is highly dense. The role of chromatin is to prevent DNA damage, regulate gene expression and DNA replication.

What is the difference between a chromosome and a chromatin?

The DNA is packaged by special proteins called histones to form chromatin. The chromatin further condenses to form chromosomes. This means chromatin is lower order of DNA organization whereas chromosomes are higher order of DNA organization.

What is another word for chromatin?

chromosome, karyon, nucleus, cell nucleus.

How many chromatin do humans have?

The complex of both classes of protein with the nuclear DNA of eucaryotic cells is known as chromatin. Histones are present in such enormous quantities in the cell (about 60 million molecules of each type per human cell) that their total mass in chromatin is about equal to that of the DNA.

How is chromatin formed?

Nucleosomes fold up to form a 30-nanometer chromatin fiber, which forms loops averaging 300 nanometers in length. The 300 nm fibers are compressed and folded to produce a 250 nm-wide fiber, which is tightly coiled into the chromatid of a chromosome.

What is chromatin material and how does it change?

Chromatin material is entangled mass of thread-like structures. Chromatin material gets organized into chromosomes, just before the cell divides.

What are the 4 stages of the cell cycle?

The cell cycle is a four-stage process in which the cell increases in size (gap 1, or G1, stage), copies its DNA (synthesis, or S, stage), prepares to divide (gap 2, or G2, stage), and divides (mitosis, or M, stage).

How does chromatin affect gene expression?

DNA is stored in a highly structured complex called chromatin. Epigenetic processes control gene expression by altering chromatin structure (Figure 1). Actively transcribed genes are associated with accessible chromatin regions, while transcriptionally silent genes are found in inaccessible chromatin regions.

Which of the following molecules is capable of targeting chromatin-remodeling?

Which of the following molecules is capable of targeting chromatin-remodeling complexes to specific DNA sequences to modify chromatin structure and activate gene expression? RISCs.

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