{"id":4302,"date":"2021-08-11T09:39:38","date_gmt":"2021-08-11T09:39:38","guid":{"rendered":"https:\/\/www.guyhowto.com\/?p=4302"},"modified":"2021-08-11T09:39:38","modified_gmt":"2021-08-11T09:39:38","slug":"plastids","status":"publish","type":"post","link":"https:\/\/www.guyhowto.com\/plastids\/","title":{"rendered":"Plastids: Structure and Presence, Origin, and Types of Plastids"},"content":{"rendered":"
Plastids<\/strong><\/h5>\n

The term Plastid is derived from Greek \u201cPlastikas\u201d which means \u201cformed or moulded\u201d. Plastids are double membrane bounded small organelles freely present in the cytoplasm<\/a> that is responsible for the storage of food, carbohydrates lipids<\/a>, and is commonly present in photosynthetic organisms like plants.<\/p>\n

These are the groups of phylogenetically and physiologically related organelles whose different types are involved in metabolism and different life activities of plants and other organisms.<\/p>\n

Structure and Presence of Plastids<\/strong><\/h5>\n

Plastids are found in all plants and a protozoan like a euglena. Plastids vary in shape. They can be spherical, disc-shaped or some are elongated with 1 \u00b5m to 1 mm in diameter. All plastids contain genome (DNA) and 70 S-type ribosomes<\/a>. Like mitochondria<\/a>, they are self-replicating organelles and contain protein-synthesizing machinery.<\/p>\n

Origin of Plastids<\/strong><\/h5>\n

The origin of plastids is described by the idea known as the endosymbiont hypothesis<\/a> that was first given by Lynn Margulis. According to this, the extant forms of present-day cyanobacteria<\/a> led to the development and evolution of plastids.<\/p>\n

They are semi-autonomous by virtue of the fact that they maintain a functional hereditary system of their own. As a result, an essential component of the biogenesis and homeostasis of plastids is the coordination of the organellar genome (plastome) with the nuclear genome.<\/p>\n

During development, many organellar genes were moved from the plastome to the nuclear genome, with the consequence that the bulk-flow of information throughout organellar advancement proceeds from the nucleus<\/a> to plastids. Nonetheless, plastid-to-nucleus signals given off by plastids (called retrograde signals) have a significant impact on the expression of numerous nuclear genes.<\/p>\n

Types of Plastids<\/strong><\/h5>\n

Plastids are classified on the basis of structure, functions, and pigments.<\/p>\n

Leucoplasts<\/strong><\/h6>\n

These are the colorless plastids present in embryonic and germ cells. They are also located in parts of the plant which do not receive light such as meristematic cells in tubers, stems, and roots.<\/p>\n

Here, leucoplasts serve as the site of starch formation and storage. Compared to plastids like chloroplast<\/a> and chromoplasts, leucoplasts do not have such pigments as chlorophyll. Additionally, they lie in deep tissue such as plant seeds and are therefore not directly exposed to light. While the primary function is storage, some of the leucoplasts are also associated with the synthesis of fats and lipids.<\/p>\n

Types of leucoplasts<\/strong><\/h5>\n