Important Types of Plastids

Plastids

(Plastos means molded) Plastids are membrane bounded organelles found in plants and photosynthetic protists( algae)

 

Types of Plastids:- there are three main types of plastids.

Chloroplasts :-(chloro means chlorophyll , plastos means molded) : Type of plastid that contain green pigment or chlorophyll is called chloroplast.

Chloroplasts are the food producers of the cell. The organelles are only found in plant cells and some protists such as algae. Animal cells do not have chloroplasts. Chloroplasts work to convert light energy of the Sun into sugars that can be used by cells. The entire process is called photosynthesis and it all depends on the little green chlorophyll molecules in each chloroplast.

STRUCTURE OF CHLOROPLAST:- Chloroplast containtwo membranes that protect the inner parts of the chloroplast. They are appropriately named the outer and inner membranes. The inner membrane surrounds the stroma and the grana (stacks ofthylakoids). One thylakoid stack is called a granum. Granum is the site for light reaction of photosynthesis while stroma is the site for dark reaction.

Leucoplasts (Leukos means white and plastos means molded“ ) are a category of plastid and as such are organelles found in plant cells. They are non-pigmented, in contrast to other plastids such as the chloroplast.Lacking photosynthetic pigments, leucoplasts are not green and are located in non-photosynthetic tissues of plants, such as roots, bulbs and seeds. They may be specialized for bulk storage of starch, lipid or protein.

 

Chromoplasts :-  (chroma means colour and plastos means molded) Chromoplasts are plastids that produce and store pigments.these are mostly present in flower petals and fruits. It gives colour to these and attract insects for pollination , thus helps in sexual reproduction.

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