What would happen if anaphase proceeded even though the sister chromatids were not properly attached to their respective microtubules and lined up at the metaphase plate?
Please answer with a long answer, if you do I'll mark your answer braininess.

The above mentioned process is more precisely known as non disjunction. The absence of this process due to the malfunctioning of the  spindle assembly checkpoint (SAC) leads to several chromosomal abnormality. Some of the associated disease are Turner syndrome, Down syndrome and Mosaicism syndrome.

Explanation:

Anaphase is a phase of mitosis and is characterized by the splitting of the replicated chromosomes and the movement of the chromatids to the terminal poles in opposite directions. Securin which serves the function of inhibitory chaperone activates separase that helps to cleave the cohesion protein. This cohesion is responsible for the attachment of sister chromatids together. Absence  of this process leads to the below mentioned medical condition.

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explanation: