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

Cells as the basic units of living organisms — practice question

A scientist performed an experiment to separate the organelles in an animal cell according to mass. First, the scientist combined the cells with a buffer solution that had the same water potential as the cells. The cells were then broken apart with a blender so that the organelles were released. The resulting mixture was filtered and then placed in a centrifuge at a speed sufficient to separate the heaviest organelle. This organelle moved to the bottom, where it formed a solid pellet, 1. The liquid remaining above pellet 1 was transferred into a clean centrifuge tube and spun in the centrifuge at a higher speed to separate the next heaviest organelle. This organelle also sank to the bottom, producing a solid pellet, 2. He carried out this process twice more to produce pellet 3 and pellet 4, with each pellet containing one organelle. What function does the organelle in pellet 4 carry out?

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

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