AP BIOLOGY

Detailed explanation-1: -The beads on string structure in chromatin is packed to form chromatin fibers that are further coiled and condensed at metaphase stage of cell division to form chromosomes.

Detailed explanation-2: -During every cell division, a cell must duplicate its chromosomal DNA through a process called DNA replication. The duplicated DNA is then segregated into two “daughter” cells that inherit the same genetic information. This process is called chromosome segregation.

Detailed explanation-3: -In interphase, the nucleus shows a network of very long extremely thin dark staining fibres called as chromatin fibres. As the cells begin to enter the first stage (prophase)of cell division, the chromatin fibres condense to form chromosomes. Thus, chromosomes are the highly condensed coiled chromatin fibres.

Detailed explanation-4: -Chromatin exists in two forms. One form, called euchromatin, is less condensed and can be transcribed. The second form, called heterochromatin, is highly condensed and is typically not transcribed. Under the microscope in its extended form, chromatin looks like beads on a string.