Why is sucrose solutions used in isolation of chloroplasts?

Question

I was reading how to isolate chloroplasts and when the leaves are being grinded they add sucrose solution and only then they centrifuge it. But it doesnt say why they do it...

Answer 1

The chloroplasts are surrounded (formed) by a double membrane that is very delicate.  Chloroplasts contain soluble molecules so the researcher tries to match the concentration of the solution of the isolation with that in the chloroplast.  A concentration too low could result in the chloroplast being rupture due to water rushing into the chloroplasts.  If the concentration is too high, water will leave the chloroplast and may disrupt the functioning of the chloroplast.