For those wanting to know what the new Snapchat emoji symbols mean, there is several different things that they repersent and these emojis have replaced the âBest Friendsâ feature with Friend Emojis smilies.
(plural tetrads) 1  A group of four things. ( 2 chemistry) A tetravalent atom or radical. ( biology) Two pairs of sister chromatids (a dyad pair) aligned in a certain way and often on the equatorial plane during the meiosis process.
There should be 23 tetrads in a human cell at the beginning of meiosis. The cell then divides twice with the chromatids separating each time. This results in four cells each of which contains 23 chromosomes (46/2). These cells are called gametes. When one gamete combines with another gamete, a zygote is formed which has 46 chromosomes. The zygote then goes through mitosis to form more cells with 46 chromosomes and those cells make up the embryo.