When cells are veryclose to one another, some of the mol-ecules on the cellsâ plasma membranesmay bind together in specific ways.Many of the important interactionsbetween cells in early developmentoccur by means of direct contact be-tween cell surfaces (figure 7.3 a).ecause these proteins may constituteless than 0.01% of the total mass of protein in a cell, puri-fying them is analogous to searching for a particular grainof sand in a sand dune! However, two recent techniqueshave enabled cell biologists to make rapid progress in thisarea. 7.1 Cells signal one another with chemicals.
The Maenads (pronounced Maynads) were female revelors in the cult of Dionysus. The god's frenzied Thracian worshippers, the Maenads, accompanied Dionysus on his travels crowned with wreaths of ivy, oak or fir and draped in the skins of animals.
Male gonad: A testis, one of a pair of organs located behind the penis in a pouch of skin called the scrotum. The testes produce and store sperm and are also the body's main source of male hormones. These hormones control the development of the reproductive organs and other male characteristics, such as body and facial hair, low voice, and wide shoulders. Last Editorial Review: 5/13/2016.