Biology 9700 · AS & A Level · Cells as the basic units of living organisms

Cells as the basic units of living organisms — practice question

An investigation was conducted to separate the cell structures in an animal cell. The cells were disrupted. The extract was filtered and transferred into a centrifuge tube. The tube was then spun so that the densest cell structure moved down first, collecting as pellet 1, as shown. The liquid above pellet 1 was decanted into a new centrifuge tube and spun again at a greater speed to separate the next densest cell structure. This cell structure settled at the bottom, forming pellet 2. The same process was carried out twice more to produce pellet 3 and pellet 4, with each pellet containing just one cell structure. What is a function of the cell structure extracted in pellet 1?

  • Adigestion of old organelles
  • Bproduction of ATP
  • Cproduction of mRNA
  • Dsynthesis of protein

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