Describe the key steps required to isolate a sample of chloroplasts from fresh spinach leaves using cell fractionation techniques.
Chloroplasts are able to synthesise some of their own proteins. Give one structure found within chloroplasts that enables translation to occur, and describe how this structure differs from its equivalent in the cytoplasm of a eukaryotic cell.
Scientists investigated the effect of magnesium deficiency on the composition of chloroplasts. They grew two groups of plants: a control group with all necessary mineral ions, and a magnesium-deficient group.
They measured the mass of protein and chlorophyll in the isolated chloroplasts and expressed them as a percentage compared to the control plants:
| Measurement | Value in magnesium-deficient chloroplasts / % of control |
|---|---|
| Mass of protein | 606060 |
| Mass of chlorophyll | 151515 |
Given that the ratio of protein to chlorophyll in the control plants is 6:16:16:1, calculate the ratio of protein to chlorophyll in the magnesium-deficient plants.
