Question

The shape of chloroplast in higher plants is
A. Discoid
B. Cup-shaped
C. Girdle shaped
D. Reticulate

Answer 1

Hint:- Some plant cells and algae have this membrane-bound cell organelle called plastid. A biologist, Ernst Hackel was the first to discover these cell organelles and name them plastids. These cell organelles have various uses to the algae and plant cells which include storage of food, aid in photosynthesis, etc. Plastids can be pigmented or contain no pigments. Chloroplasts are pigmented plastids found in higher plants and some algae.

Complete Answer:-
Chloroplasts have the pigment chlorophyll in them; this enables the organism or the plant to produce its own food by photosynthesis. Light absorbed by these pigments helps in the conversion of carbon dioxide and water to carbohydrates.
This cell organelle is membrane-bound and encloses within itself an aqueous fluid called stroma, thylakoids arranged in stacks called grana, and stromal lamellae that connects one granum to another. Higher plants have twenty to forty chloroplasts per cell. This number varies in different organisms. The thylakoid membrane contains the chlorophyll pigments. Along with different chlorophyll pigments, thylakoids also contain carotenoids, phycobilins, and xanthophylls.
Chloroplasts come in different shapes- discoid, cup-shaped, girdle shaped, reticulate, plate-like, ribbon-shaped, or even spiral. Cup-shaped chloroplasts are found in organisms such as Chlamydomonas, a green alga. Girdle shaped chloroplasts are found in organisms such as the filamentous green algae Ulothrix. Reticulate chloroplasts are found in the free-living, filamentous green algae Oedogonium. Higher plants have oval, discoid shaped chloroplasts.


The correct option is (A). The shape of chloroplast in higher plants is discoid.
 

Note:- Chloroplasts are semiautonomous cell organelles. They have their own circular DNA and ribosomes. Chloroplasts are dimorphic i.e. they have two very different forms. The mesophyll cells of ${C_3}$ and ${C_4}$ plants have this granal form of the chloroplast. The other form is agranal and as the name suggests these chloroplasts lack grana. They only have stroma and stromal lamellae. They are found in the bundle sheath cells of ${C_4}$ plants.