Meiosis

Mitosis and Meiosis

Mrs. Clayborne Biology

​Comparing Mitosis and Meiosis

Cells divide in two ways:

​

Somatic Cells divide by Mitosis.

​

Gametes are produced by Meiosis.​

Biology

​Mitosis Highlights

• Results in TWO daughter cells

• Daughter cells are DIPLOID - 2N chromosomes

• Daughter cells are GENETICALLY IDENTICAL​

Biology​

​Meiosis Highlights

• ​Also known as "Reduction Division"

• Results in FOUR daughter cells

• Daughter cells are HAPLOID - N chromosomes

• Daughter cells are each GENETICALLY DIFFERENT

Biology​

​Definitions

Meiosis

​

Cell reproduction where number of chromosomes are reduced by half.

​

Homologous chromosomes seapratated producing 4 haploid cells​.

​

Required for sexual reproduction​.

Biology

Mitosis​

​

Cell reproduction​ maintains number of chromosomes.

​

Sister chromatids separated producing 2 diploid cells.

​

Required for growth, to repair/replace.​

​Steps

Meiosis I

​

Prophase I

Metaphase I

Anaphase I

Telophase I

Cytokinesis​ I

​

Biology

Mitosis​

​

Prophase

Metaphase

Anaphase

Telophase​

Meiosis II

​

Prophase II

Metaphase II

Anaphase II

Telophase II

Cytokinesis​ II

​

Meiosis

​Type of Division & Cell Type

Meiosis

​

Sexual

​

Gametes​/Sex Cells

Biology

Mitosis​

​

Asexual

​

Somatic Cells​

​Location

Biology

Mitosis​

​

Eukaryotes that reproduce sexually.​

​

Nearly all cells in organism.​

​

*NOT in Archea or Bachteria​

Meiosis

​

ALL organisms​

​

Only in sex organs​

​Genetic Make-up & Function

Biology

Mitosis​

​

ALL organisms.

​

Growth, repair and

replacement of cells.

​

​

Meiosis

​

Ensures genetic diversity of species.

​

Sexual reproduction.​

​Divisions and Daughter Cells

Biology

Mitosis​

​

ONE Division.

​

2 diploid daughter cells.

​

​

Meiosis

​

TWO Divisions​.

​

4 haploid cells.​

​Crossing Over & Homologues

Biology

Mitosis​

​

​No crossing over.

​

No pairing of Homologues.

​

​

Meiosis

​​

Mixing of chromosomes/genes can occur.

​

Homologous Pairs.​

​

​Results in...

Biology

Mitosis​

​

Two identical daughter cells.

​

All cells EXCEPT gametes (sex cells) result from Mitosis.​

​

​

Meiosis

​​

Gametes - Sex cells only.

​

Female - egg cells

Male - sperm cells​

​

Multiple Choice

Which of the following is NOT a stage of Mitosis?

• Prophase

• Metaphase

• Cytokinesis

• Telophase

Multiple Choice

During Mitosis Telophase, the...

• cytoplasm divides.

• nuclear membrane dissolves.

• chromosomes line up in the center of the cell.

• None of the above.

Multiple Choice

A spindle fiber ...

• pulls the chromosomes to the centrioles.

• causes the centromeres to divide.

• makes the nuclear envelope dissolve.

• is made of nine triplets of microtubules.

Multiple Choice

Crossing-over occurs during ___________ in MEIOSIS.

• Prophase II

• Prophase I

• Fertilization

• Metaphase II

Multiple Choice

Which of the following does NOT provide new genetic combinations?

• Random fertilization.

• Cytokinesis

• Independent assortment

• Crossing-over

Multiple Choice

Spermatogenesis results in

• two haploid cells

• three polar bodies

• one haploid sperm cell and three polar bodies

• four haploid sperm cells

Multiple Choice

Oogenesis results in

• chromosomes becoming visible

• one egg cell and three polar bodies

• four haploid cells

• the exchange of chromatid portions between homologous chromosomes

Multiple Choice

Crossing-over is...

• chromosomes becoming visible

• one egg cell and three polar bodies

• four haploid cells

• the exchange of chromatid portions between homologous chromosomes