AP BIOLOGY

Detailed explanation-1: -A chromatid is one of the two identical halves of a chromosome that has been replicated in preparation for cell division. The two “sister” chromatids are joined at a constricted region of the chromosome called the centromere.

Detailed explanation-2: -In the S phase (synthesis phase), DNA replication results in the formation of two identical copies of each chromosome-sister chromatids-that are firmly attached at the centromere region. At this stage, each chromosome is made of two sister chromatids and is a duplicated chromosome.

Detailed explanation-3: -After DNA replication, each chromosome now consists of two physically attached sister chromatids. After chromosome condensation, the chromosomes condense to form compact structures (still made up of two chromatids).

Detailed explanation-4: -At this stage (after DNA replication but before cell division), each chromosome consists of two identical “chromatids” (the results of DNA replication) connected at a special structure called the “centromere".

Detailed explanation-5: -The primary function of sister chromatids is to pass on a complete set of chromosomes to all the daughter cells formed as a result of cell division. During mitosis, they are attached to each other through the centromere – a stretch of DNA that forms protein complexes.