Practice question

Dounce homogenizer is a manual tissue grinder consisting of a glass tube and tightly fitting pestle with narrow clearance. Cells suspended in buffer are forced through this narrow annular space, generating mechanical shear and pressure differentials that rupture plasma membranes while preserving organelles if clearance is controlled. This contrasts with bead beater which uses bead collision, sonicator which uses acoustic cavitation, and freeze-thaw which uses ice crystal damage. Dounce is gentle, ideal for preparing nuclei and subcellular fractions without vigorous denaturation of sensitive complexes.