Answer to Question #51270 in Biology for abby

Question

Explains how the chromosomes of disjunction process during meiosis is similar to the act of distributing playing cards.

Answer 1

The main difference between mitosis and meiosis is that meiosis takes one diploid (two copies of each chromosome) cell and makes four haploid (one copy of each chromosome) cells that form the gametes (sex cells). Meiosis has two cell divisions (Meiosis I and Meiosis II), resulting in four haploid cells.

Imagine a deck of 46 cards, 44 cards with two jockers. Let homologous pairs be the cards of same value and same color, i.e. red 5s form homologous pair, and jockers are chromosomes. Thus, we have 23 pairs of chromosomes. Mitosis makes an identical deck from existing one, after it we will have 2 decks with 46 cards each, these 2 decks are identical. Meiosis makes a new deck and then shuffles the cards. After it we have 2 splitted decks (4 half-decks by 23 cards).

Starting with 23 cards before S-phase, we have 23 pairs of cards after it (they are homologous pairs). In Metaphase I chromosomes are lined up along the equator, unlike mitosis. They align in completely random way, either red cards from one side, black cards from the other side, or red cards are mixed with black cards. During Anaphase I the disjunction takes place, and the cards are shuffled now. During further processes they go to two different cells during Phase I of meiosis, and each of these cells forms another one during Phase II of meiosis.