NAME: ______ MeiosisMrs. Price----BIOLOGY

Each organism inherits a ______copy of every gene from each of its “______” through gametes.

Gametes are formed by a process that ______the two sets of genes so that each gamete ends up with just ______set.

Chromosome Number

-All organisms have ______numbers of ______.

A body cell in an adult fruit fly (Drosophila) has __ chromosomes: 4 from the fruit fly's male parent, and 4 from its ______parent.

These sets of chromosomes are ______.

Each of the 4 chromosomes that came from the male parent has a ______chromosome from the female parent.

A cell that contains ______sets of homologous chromosomes is said to be ______.

The number of chromosomes in a ______cell is sometimes represented by the symbol ____.

For Drosophila, the diploid number is 8, which can be written as ______

The gametes of ______reproducing organisms contain only a ______set of chromosomes, and therefore only a single set of ______.

These cells are ______. Haploid cells are represented by the symbol ___.

For Drosophila, the haploid number is 4, which can be written as N=4.

Phases of Meiosis

Meiosis is a process of ______division by half by separating ______chromosomes in a diploid cell.

Meiosis involves _____ divisions:

•meiosis I

•meiosis II.

By the end of meiosis II, one ______cell that entered meiosis has become ____ haploid cells.

Meiosis I

______& ______

Interphase I

•DNA replication forms ______chromosomes.

Meiosis I: Prophase I

When homologous chromosomes form tetrads in meiosis I, they ______portions of their ______in a process called ______over.

Crossing-over produces ____ combinations of alleles.

Meiosis I: ______I

•______fibers attach to the chromosomes.

Meiosis I: Anaphase I

•The fibers ______the homologous chromosomes toward ______ends of the cell.

Meiosis I: Telophase I and ______

•Nuclear ______form.

•The cell separates into _____ cells.

The two cells produced by meiosis I have chromosomes and ______that are different from each other and from the ______cell that entered meiosis I.

Meiosis II

The ____cells produced by Meiosis I now enter a second meiotic division.

  • Unlike meiosis I, ______cell goes through chromosome replication.
  • Each of the cell’s chromosomes has ___ chromatids.

Meiosis I results in :

  • two haploid (N) ______cells, each with _____ the number of chromosomes as the original cell.
  • Prophase II

Meiosis II: Metaphase II

•The chromosomes ____ up in the center of cell.

Meiosis II: Anaphase II

•The sister chromatids ______and move toward opposite ends of the cell.

Meiosis II: Telophase and Cytokinesis

  • Meiosis II results in _____ haploid (N) daughter cells.

Gamete Formation

In male animals, meiosis results in _____ equal-sized gametes called ______.

In many female animals, only ___ egg results from meiosis. The other three cells, called _____ bodies, are usually not involved in ______.

Comparing Mitosis and Meiosis

  • Mitosis results in the production of ____ genetically identical ______cells.
  • Meiosis produces _____ genetically different ______cells.

Mitosis

•Cells produced by mitosis have the ______number of chromosomes and alleles as the original cell.

•Mitosis allows an organism to _____ and ______cells.

•Some organisms reproduce ______by mitosis.

Meiosis

•Cells produced by meiosis have ______the number of chromosomes as the parent cell.

•These cells are ______different from the ______cell and from each other.

•Meiosis is how ______-reproducing organisms produce gametes.

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