Biology 9700 · AS & A Level · The microscope in cell studies

The microscope in cell studies — 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 open using a blender so that the organelles were released. After the mixture had been filtered, it was placed in a centrifuge and spun at high speed so that the heaviest organelle was separated out. This settled at the base, producing a solid pellet 1. The liquid above pellet 1 was transferred into a fresh centrifuge tube and spun in the centrifuge at a greater speed to separate the next heaviest organelle. This organelle also settled at the bottom, forming a solid pellet 2. He carried out this method twice more to produce pellet 3 and pellet 4, each of which contained one organelle. What is the function of the organelle extracted in pellet 2?

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

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