Question

Plastids are present only in
(a) Animal cells
(b) Viruses
(c) Plant cells
(d) None of the above

Answer 1

Hint: The plastid is a membrane-bound organelle. They are derived from proplastids, which are present within the meristematic regions. Plastids are the location of synthesis and storage of important chemical compounds employed by the cells of autotrophic eukaryotes.

Complete answer:
Plastids are the cytoplasmic organelles present only in plant cells. Plastids contain chlorophyll which gives green colour to plants. It performs photosynthesis and is called chloroplasts. They can store products like starch and may synthesize fatty acids and terpenes, which may be used for producing energy and as a staple for the construction of other molecules. Animal cells and viruses do know to participate in photosynthesis as they lack plastids and make their own food.

Additional information:
On the idea of pigments present, plastids are of three types which are –
> Leucoplasts: It is a colourless plastid and is present in underground roots, stems. Leucoplasts store the starch grain and the oil drops. There are three types of leucoplasts named amyloplasts, proteinoplasts, and elaioplasts.

> Chloroplasts: It is green coloured plastic. Chloroplasts are mainly for photosynthesis. They're found in the leaves of the plants.

> Chromoplasts: It is a coloured plastid aside from green. Chromoplasts are liable for the characteristic colour of flowers and fruit. They're involved in attracting insects, various vectors for pollination and for fruit dispersal.

So, the right answer is ‘Plant cell’.

Note:
-Most of the plastids that are responsible for photosynthesis have numerous internal membrane layers.
-Plastids have a common evolutionary origin and possess a double-stranded DNA molecule that is circular. It is similar to the circular chromosome of prokaryotic cells.
-Plastids were first discovered and named by Ernst Haeckel, but A. F. W. Schimper first gave a clear definition.