is that they are inherited from female parent only. Mitochondrial DNA comparisons are used to trace human origins. It is also used to track and date recent evolutionary time because it mutates to time faster than DNA in the nucleus. .
. Plastids The term plastid is derived from the Greek word Platikas (formed/moulded) and used by A.F.U. Schimper in . He classified plastids into following types according to their structure, pigments and function.
Plastids multiply by fission. Plastids Chromoplasts Leucoplasts Coloured Plastids Colourless plastids store food materials Chloroplast Occurs in green algae and higher plants. Pigments chlorophyll a and b Amyloplast – stores – starch Phaeoplast Brown algae and dinoflagellates. Pigment- fucoxanthin Elaioplast – store – lipids (oils).
Seed of monocot and dicots. Rhodoplast Red algae Pigment- Phycoerythrin Aleuroplast (or) Proteoplast Stores – Protein According to Schimper, different kind of plastids can transform into one another. Chloroplasts Leucoplasts Chromoplasts (contains carotenoids) . .
Chloroplast Chloroplasts are vital organelle found in green plants. Chloroplast has a double membrane the outer membrane and the inner membrane separated by a space called periplastidial space . The space enclosed by the inner membrane of chloroplast is filled with gelatinous matrix, lipo-proteinaceous fluid called stroma . Inside the stroma there are flat interconnected sacs called thylakoid .
The membrane of thylakoid enclose a space called thylakoid lumen . Grana (singular: Granum) are formed when many of these thylakoids are stacked together like pile of coins. Light is absorbed and converted into chemical energy in the granum, which is used in stroma to prepare carbohydrates. Thylakoid contain chlorophyll pigments.
The chloroplast contains osmophilic granules, 70s ribosomes, DNA (circular and non histone) and RNA. These chloroplast genome encodes approximately proteins involved in photosynthesis including the components of photosystem I & II, cytochrome bf complex and ATP synthase. One of the subunits of RuBisco is encoded by chloroplast DNA. It is the major protein component of chloroplast stroma, single most abundant protein on earth.
The thylakoid contain small, rounded photosynthetic units called quantosomes . Chloroplast is a semi-autonomous organelle and