Updated: Question in GATE 2012 Life Scinces Paper with Solution

A question in GATE 2012 Life Scinces Paper with Solution has been updated:

Transformation of normal cyanobacterial cells into heterocysts involves

1. loss of nitrogenase but retention of photosystem I
2. loss of both nitrogenase and photosystem I
3. synthesis of nitrogenase and retention of photosystem I
4. synthesis of nitrogenase and loss of photosystem I