The nucleosome hypothesis proposed by Roger Kornberg in 1974 was a paradigm shift for understanding eukaryotic gene expression. The assembly of DNA into chromatin involves a range of events, beginning with the formation of the basic unit, the nucleosome, and ultimately giving rise to a complex organization of specific domains within the nucleus. The first step is the assembly of [...]
Vacuoles (means "empty space") are cavities in the cytoplasm (especially in plant cells) surrounded by a cytoplasmic membrane, the tonoplast, and filled with a watery fluid called the cell sap containing water and various substances in solution or suspended state. Plants cells have very large distinct vacuoles while in animals, vacuoles are smaller in size. The Plant vacuoles tend to [...]
Mitochondrial DNA is a double stranded circular molecule, which is inherited from the mother in all multi-cellular organisms, though some recent evidence suggests that in rare instances mitochondria may also be inherited via a paternal route. Typically, a sperm carries mitochondria in its tail as an energy source for its long journey to the egg. When the sperm attaches to [...]