Question

Which of the following is found only in a plant cell?
(A)Mitochondria
(B)Lysosomes
(C) Glycogen
(D)Plastids

Answer 1

Hint: The organelle which is found only in plants is a double membrane and is known to be responsible for the manufacturing and storing of food. These organelles may contain some or the other type of pigments associated with them.

Complete answer: The plastid is a double-membrane organelle found within the cells of plants and algae. Plastids or chloroplasts aren't found within the animal cells. Plastids are known to be the sites of manufacture and storage of important chemical compounds employed by the cell. They often contain pigments utilized in photosynthesis and therefore the varieties of pigments present can change or determine the cell's colour. They have a typical origin and possess a double-stranded DNA molecule that's circular like that of prokaryotes.

Additional Information: A plastid that does not contain any pigments is called leucoplast, and it is involved mainly in storing food. The leucoplasts are mainly classified into three types: an amyloplast that stores starch, an amyloplast that stores fat, or an aleuroplast that stores proteins.
-Plastids with chlorophyll (green pigment) are called chloroplasts. They give the plant parts the green colour. These plastids are involved in photosynthesis.
-Those that have other pigments are called chromoplasts. They are involved in
producing and storing pigments, e.g. carotene, xanthophylls, etc. They abound
in fruits, flowers, and roots.
-The leucoplast is a plastid that lacks pigments and is involved mainly in storing
food. Tannosomes are also a type of leucoplast which are involved in the
synthesis of tannins and polyphenols.

So, the correct answer is ‘Plastids’.

Note: Like mitochondria, plastids have their own DNA and ribosomes. The DNA of plastid appears as large protein-DNA complexes united with the inner envelope membrane and are termed 'plastid nucleoids'. Each nucleoid may comprise more than 10 copies of the plastid DNA.