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.
Testosterone is the sex hormone produced in male gonads. In females, ovum develops in the ovary. Ovaries are paired organs in the lower abdominal cavity, and are responsible for the production of female sex hormone called estrogen. Gonads are the sites (or organs) where gametes are produced. â¢ Gonads of the male are called testes, whereas gametes of the male are called sperms. â¢ Gonads of the female are called ovaries, whereas gametes of the female are called ova. â¢ Gonads are the organs, whereas gametes are the haploid sex cells.