BIO 325 Chapter Notes - Chapter 14: Heteroplasmy, Chloroplast Dna, Nuclear Dna

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Mitochondria and chloroplasts, organelles key to providing energy for cellular metabolism, have their own genomes. Because scientists think that these organelles originated from bacterial cells that established a symbiotic relationship with the ancient precursors of eukaryotic cells, it makes sense that mtdna (mitochondrial dna) and cpdna (chloroplast dna) are circular molecules. Just like mutations in nuclear genes, mutations in organellar genes can affect an organism"s phenotype. Organelles are usually, but not always, inherited maternally in the egg cytoplasm. Human mitochondrial dnas are maternally inherited, so mutations in mitochondrial genomes can result in a variety of human diseases that display non-mendelian maternal inheritance. Because of these facts, different cells in an individual may have different proportions of wild-type and mutant organellar genomes, adding complexity to the relationship of organellar genotype and phenotype. Key terms mitochondria organelles that convert energy derived from nutrient molecules into. No reproduction or distribution without the prior written consent of mcgraw-hill education.