The compartmentation of genetic information is a fundamental feature of the eukaryotic cell. The metabolic capacity of a eukaryotic (plant) cell and the steps leading to it are overwhelmingly an endeavour of a joint genetic cooperation between nucleus/cytosol, plastids, and mitochondria. Alter ation of the genetic material in anyone of these compartments or exchange of organelles between species can seriously affect harmoniously balanced growth of an organism. Although the biological significance of this genetic design has been vividly evident since the discovery of non-Mendelian inheritance by Baur and Correns at the beginning of this century, and became indisputable in principle after Renner's work on interspecific nuclear/plastid hybrids (summarized in his classical article in 1934), studies on the genetics of organelles have long suffered from the lack of respectabil ity. Non-Mendelian inheritance was considered a research sideline~ifnot a freak~by most geneticists, which becomes evident when one consults common textbooks. For instance, these have usually impeccable accounts of photosynthetic and respiratory energy conversion in chloroplasts and mitochondria, of metabolism and global circulation of the biological key elements C, N, and S, as well as of the organization, maintenance, and function of nuclear genetic information. In contrast, the heredity and molecular biology of organelles are generally treated as an adjunct, and neither goes as far as to describe the impact of the integrated genetic system.
Lakhmir Singh's Science is a series of books for Classes 1 to 8 which conforms to the NCERT syllabus. The main aim of writing this series is to help students understand difficult scientific for each class that is available concepts in a simple manner in easy language.
"Essential reading for anyone who wants to understand history – and then go out and change it." –President Barack Obama Nelson Mandela was one of the great moral and political leaders of his time: an international hero whose lifelong dedication to the fight against racial oppression in South Africa won him the Nobel Peace Prize and the presidency of his country. After his triumphant release in 1990 from more than a quarter-century of imprisonment, Mandela was at the center of the most compelling and inspiring political drama in the world. As president of the African National Congress and head of South Africa's antiapartheid movement, he was instrumental in moving the nation toward multiracial government and majority rule. He is still revered everywhere as a vital force in the fight for human rights and racial equality. Long Walk to Freedom is his moving and exhilarating autobiography, destined to take its place among the finest memoirs of history's greatest figures. Here for the first time, Nelson Rolihlahla Mandela told the extraordinary story of his life -- an epic of struggle, setback, renewed hope, and ultimate triumph. The book that inspired the major motion picture Mandela: Long Walk to Freedom.