Question

The colourless plastids are called as……………….and their main function is …………….
(a) Chloroplasts, photosynthesis
(b) Leucoplasts, respiration
(c) Chromoplasts, protection from sunlight
(d) Leucoplasts, storage of food

Answer 1

Hint: Plastids are membrane-bound organelles present in eukaryotes which helps in storage and synthesis of various organic compounds. It is mainly found in plant cells and protists and divided into three types on basis of its colour and functions.

Complete Answer:
The colourless plastids are called the leucoplast and their main function is the storage of food. Leucoplast is oval, spherical and rod in shape. It is found in fruits, seeds, tubers, and rhizomes of a plant and mainly stores food in the form of carbohydrates, lipids and proteins.

Based on storage, it is divided into amyloplasts, elaioplasts and aleuroplasts. Amyloplasts store starch in the form of simple or compound starch grains, elaioplasts store fats and aleuroplasts store protein in amorphous and crystalloids form.

Additional information: Chromoplasts are coloured plastids with the presence of red, yellow and orange pigments like xanthophyll and phycoerythrin. These pigments are fat-soluble carotenoids which form either from leucoplasts or chloroplasts. It also provides colour to many flowers and fruits.
Chloroplasts are green coloured plastids which help in photosynthesis. It only consists of chlorophyll pigments. Chloroplast helps in the synthesis of organic food from inorganic substances with the help of sunlight. Chloroplast number and size varies from species to species. In case of numbers, it ranges from one chloroplast one cell to hundred of chloroplasts in one cell.
So, the correct answer is ‘(d) Leucoplast, storage of food.’

Note: Plastids are considered as a semi-autonomous organelle due to the presence of its DNA and double membrane-bound organelles. This DNA is mainly found in chloroplast which helps in replication, transcription, synthesis of enzyme and production of proteins. The chloroplast is symbiotic in origin as mitochondria.