The point of attatchment between two chromatids is called the centromere. When two chromatids are connected, it is called a chromosome which is essential in DNA replication, or, mitosis.
centromere
Two pairs of chromatids lying side by side are referred to as a tetrad.
2.25
2.25
sister chromatids
Chiasmata, coz they didnt say two chromatids (most probably)
centromere
Recall the Wobble-Base - here is a Wobble-Answer: This protein disk is called the di-Chromosome Centromere assembly disk [it brings - and temporarily Locks - the centromeres of the pair of Chromosomes together].
A chromosome is determined to be metacentric, acrocentric or telocentric by the location of its centromere. Centromeres are the point of attachment of two sister chromatids. Sister chromatids are formed during DNA replication prior to mitosis or meiosis. Chromosome Y by itself (when it is not replicating and there are no sister chromatids) is not acrocentric, as it wouldn't even have a centromere location.
centromere
centromere
The two chromatids of a chromosome are attached at a point called the centromere. It is the point which it is attached to a spindle fiber during the process of cell division.
x and y chromosomes
Centromere!
Origin and Insertion One of the points of attachment is the ORIGIN (typically the non-moving point of attachment). The other point of attachment is the INSERTION (typically the moving point of attachment). For example - when the brachialis muscle (located on the upper arm) contracts - it shortens the distance between the origin (on the humerus - the upper arm bone and the insertion (on the radius - the forearm bone). The humerus does not move, but the radius does move - it moves closer to the humerus.
Two sets of sister chromatids .
The two attachment points are the origin and insertion. The origin is the immovable (or slightly moveable point. The insertion is the movable point. The insertion always moves towards the origin.