Biology Notes

Definition Prophase For both mitosis and meiosis, prophase is the phase that follows interphase and is usually the first and longest phase in the cell cycle. The chromosomes are visible during this phase of DNA unwinding and chromatin condensation.  What Happens in Prophase? During prophase, the DNA that was generated during the interphase phase is … Read more

Definition of Centrioles Near the nucleus, eukaryotic cells include two cylindrical, rod-shaped microtubular structures called centrioles. They are found in most algal cells (with the exception of red algae), moss cells, some fern cells, and most mammal cells, and lack a limiting membrane and DNA or RNA. Prokaryotes, red algae, yeast, cone-bearing and flowering plants … Read more

Prokaryotic Cells Definition Prokaryotic cells are single-celled organisms that lack a membrane-bound nucleus and other organelles, making them primitive in form and function. The name “prokaryote” comes from two Greek words: “pro” for “before” and “karyon” for “nucleus.” Prokaryotes, the simplest form of life, are thought to be the first living species on the planet. … Read more

Mitochondria Definition Mitochondria are oxygen-consuming ribbon-shaped cellular organelles that float freely within the cell. They are called as the “powerhouse of the cell” because they provide all of the cell’s biological energy by oxidising the available substrates. The mitochondrial enzymatic oxidation of chemical molecules releases energy. Because mitochondria serve as energy generators, they can be … Read more