In a chloroplast isolation lab using spinach leaves, why does everything have to be kept cold?

I've heard it helps maintain chloroplast activity, but what exactly does that mean?In a chloroplast isolation lab using spinach leaves, why does everything have to be kept cold?
Since your spinach leaves probably aren't attached to the plant any more, the cells in those leaves no longer have access to the nutrients and water in the soil. The cells need nutrients and water from the soil to power the chemical reactions that keep them alive. So now that they've been cut off from the source, they are going to run out of nutrients/water and eventually die.





By keeping the leaves cold, you slow down the rate of all the chemical reactions happening in those cells. Since the reactions are occurring more slowly, it will take longer for the cells to run out of nutrients and water. In essence, you're prolong the cells' lifespans. That gives you more time to work with the leaf and isolate your chloroplasts before all the cells (and organelles within them) die.