Question
Question: Where in a plant cell are chloroplasts found?...
Where in a plant cell are chloroplasts found?
Solution
Chloroplasts are a form of plastid, which is a circular, oval, or disk-shaped entity involved in food synthesis and storage. The presence of two pigments, chlorophyll a and chlorophyll b, distinguishes chloroplasts from other types of plastids by their green colour.
Complete answer:
Chloroplasts have a diameter of 5–7 m and a thickness of 1–2 m (1 m = 0.001 mm). They are protected by the chloroplast envelope, which is made up of a double membrane with outer and inner layers separated by an intermembrane space. The thylakoid membrane is a third internal membrane that is substantially folded and characterised by the presence of closed discs (or thylakoids). Thylakoids are organised in compact stacks termed grana in most higher plants (singular granum). Grana are linked by stromal lamellae, which are extensions that go from one granum through the stroma and into another.
The thylakoid membrane envelops the thylakoid lumen, a central watery region. The stroma, a matrix comprising dissolved enzymes, starch granules, and copies of the chloroplast genome, fills the area between the inner membrane and the thylakoid membrane.
Chlorophylls and several protein complexes, such as photosystem I, photosystem II, and ATP, are housed in the thylakoid membrane, which are specialised for light-dependent photosynthesis.
Chloroplasts can be found in all green tissues or cells of plants, although they are concentrated in the parenchyma cells of the leaf mesophyll.
Note:
One of the functions of such pigments is to absorb light energy for the photosynthesis process. Other pigments found in chloroplasts, such as carotenoids, act as accessory pigments, capturing solar energy and passing it on to chlorophyll.