Presentation on theme: "Meiosis Haploid (n)-- one set of chromosomes Diploid (2n)-- two sets of chromosomes Most plant and animal and adult cells are diploid (2n) Eggs and sperm."— Presentation transcript:
Haploid (n)-- one set of chromosomes Diploid (2n)-- two sets of chromosomes Most plant and animal and adult cells are diploid (2n) Eggs and sperm are haploid (n) Meiosis is a process to convert a diploid cell to a haploid gamete, and cause a change in the genetic information to increase diversity in the offspring.
Interphase During this stage, each individual chromosome replicates,
Prophase 1 Each chromosome then actively seeks out its homologous chromosome, as shown in the graphical representation. After the homologous chromosomes pair, the structure is referred to as a tetrad (four chromatids)
Metaphase 1 At metaphase, each chromosome has reached its maximum density. The homologous pairs allign at the center of the cell. Small fibers attach to the centromere.
Anaphase 1 Anaphase I pulls apart the tetrad, separating each homologous chromosome.
Telophase 1 two nuclear envelopes begin to surround the separate chromosomes and two separate cells form
Prophase2 During Prophase II, each dyad (1/2 a tetrad) is composed of a pair of sister chromatids and they are connected by a centromere Begins to move toward center of cell
Metaphase2 Metaphase II is similar to Metaphase I in that the dyads are lined up at a metaphase plate by the spindle fibers.
Anaphase 2 Anaphase II separates the dyads into individual chromatids. Each sister chromatid ends up on one side of the cell.
Telophase2 At the end of Telophase II, the nuclear envelopes forms around each set of DNA and the cytoplasm divides once again. As a result, four haploid cells have formed from one diploid cell. The chromosomal content of a haploid cell in one-half the chromosomal content of a diploid cell ( n as opposed to 2n )one-half the chromosomal content
Two Laws Mendel's Law of Segregation states that the 2 alleles of each gene pair separate into different gametes (egg or sperm) as these are formed prior to reproduction.
The law of independent assortment: during gamete formation the segregation of the alleles of one allelic pair is independent of the segregation of the alleles of another allelic pair