Answer: The end of the centrifugation is microsomal fraction
Explanation:
A chunk of tissue being treated for its cell's membrane to break and release the contents inside describes the process of HOMOGENIZATION.
After homogenization, the various cell components (nuclei, mitochondria, Microsomes etc) can be separated by step-by-step fashion of differential centrifugation based on their size
At low speed, nuclei fraction is collected due to its larger size
At high speed, mitochondrial fraction is collected
At the much higher speed (usually the end) microsomal fraction is collected due to its microscopic size