During the S phase, DNA is synthesized to make two identical copies; each chromosome replicates to make a paired chromatid. These chromatids are joined by a protein link called a kinetochore which holds the pair together until mitosis.
What happens to chromatin in S phase?
During S phase of the eukaryotic cell division cycle, newly replicated DNA is rapidly assembled into chromatin. Newly synthesised histones form complexes with chromatin assembly factors, mediating their deposition onto nascent DNA and their assembly into nucleosomes.
What happens to chromatin in G1 phase?
Cells in G1 phase exhibit subnuclear domains with some regions associated with nuclear pores and nuclear lamina. Pre-RCs preferentially form at accessible chromatin. … During mitosis, chromosomes condense and many transcription factors and chromatin binding proteins are ejected from the chromatin.
Why do mutations occur in S phase?
Gene mutation has to do with the duplication of the DNA, and if something wrong goes with this duplication, then the new DNA will not be exactly like the original one. This duplication happens in the S phase. Chromosomal mutation are either having an extra or missing piece, or having an extra or missing chromosome.
How does a chromosome duplicate?
Chromosome duplication: Part of a chromosome in duplicate. … Duplications typically arise from an event termed unequal crossing-over (recombination) that occurs between misaligned homologous chromosomes during meiosis (germ cell formation).
Is chromatin made of DNA?
Chromatin is a complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells. Each nucleosome is composed of DNA wrapped around eight proteins called histones. …