A researcher disrupts cells and separates subcellular components using centrifugation.Which of the following correctly lists the order in which cellular components will pellet when disrupted cell mixtures are centrifuged at increasingly higher speeds?
A)ribosomes,nuclei,mitochondria
B)chloroplasts,ribosomes,pieces of membrane
C)nucleus,ribosomes,chloroplasts
D)nucleus,mitochondria,ribosomes

Question

Quizplus · Accepted Answer

When disrupted cell mixtures are centrifuged at increasingly higher speeds, the larger and denser components will pellet first, followed by smaller and less dense components. In general, the order of pelleting is nuclei > mitochondria > ribosomes. Therefore, choice D is the correct order of pelleting: nucleus first, followed by mitochondria, and then ribosomes. Choice A is incorrect because ribosomes are much smaller and less dense than nuclei and mitochondria, and would not pellet before them. Choice B is incorrect because chloroplasts are only present in plant cells and would not be present in all cell types. Choice C is incorrect because chloroplasts would not pellet before ribosomes, and because nuclei are larger and denser than ribosomes and would pellet first.

A Researcher Disrupts Cells and Separates Subcellular Components Using Centrifugation