Where did plastids originate? Their origin is explained by endosymbiosis, the act of a unicellular heterotrophic protist engulfing a free-living photosynthetic cyanobacterium and retaining it, instead of digesting it in the food vacuole (Margulis 1970; McFadden 2001; Kutschera & Niklas 2005).

How plastids are formed?

It is generally accepted that plastids first arose by acquisition of photosynthetic prokaryotic endosymbionts by non-photosynthetic eukaryotic hosts. It is also accepted that photosynthetic eukaryotes were acquired on several occasions as endosymbionts by non-photosynthetic eukaryote hosts to form secondary plastids.

Are plastids found in animal cell?

Plastids are the cytoplasmic organelles present only in plant cells. Plastids contain chlorophyll which gives green colour to plants. ... Animal cells and viruses do know to participate in photosynthesis as they lack plastids and make their own food.