Royal jelly, a thick, milky substance secreted by young nurse honeybees to feed a bee colonyâs larvae, most notably the queen larvae, is a rich source of nutrients, as well as acetycholine, a neurotransmitter that plays a critical role in cognitive function.
The origin of the eukaryotic cell is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The timing of this series of events is hard to determine; Knoll (2006) suggests they developed approximately 1.6â2.1 billion years ago.
Biologists recognize 2 basic cell types: prokaryotic and eukaryotic. The earliest cells on earth were relatively simple prokaryotic cells. Over billions of years, some of these early prokaryotic cells evolved into present-day prokaryotic cells, while others evolved into much larger and more complex eukaryotic cells.he interior of eukaryotic cells is generally divided into many specialized compartments by internal membranes (membranes separate from the plasma membrane) and membrane-bound organelles (organelles completely surrounded by membranes). Usually, prokaryotic cells lack internal membranes and membrane-bound organelles.