Mitosis and Meiosis!

Study Guide: Mitosis and Meiosis

Mitosis

• Definition: Mitosis is the process of cell division that results in two identical daughter cells, each with the same number of chromosomes as the parent cell.

• Phases of Mitosis:

  1. Prophase: Chromatin condenses into chromosomes, and the nuclear envelope breaks down.

  2. Metaphase: Chromosomes line up at the cell's equatorial plane.

  3. Anaphase: Sister chromatids are pulled apart towards opposite poles.

  4. Telophase: Nuclear envelopes reform around each set of chromosomes, which decondense back into chromatin.

  5. Cytokinesis: The cytoplasm divides, resulting in two separate cells.

Meiosis

• Definition: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in four genetically different gametes (sperm or eggs).

• Phases of Meiosis (Meiosis I):

  1. Prophase I: Homologous chromosomes pair up to form tetrads, and crossing over occurs.

  2. Metaphase I: Tetrads align at the cell's equator.

  3. Anaphase I: Homologous chromosomes are pulled apart to opposite poles.

  4. Telophase I: Nuclear envelopes may reform, and the cell divides (Cytokinesis).

  5. Result: Two haploid cells are formed; each has half the number of chromosomes as the original.

Key Differences Between Mitosis and Meiosis:

• Mitosis results in 2 identical cells; Meiosis results in 4 genetically varied gametes.

• Mitosis is for growth and repair; Meiosis is for sexual reproduction.

Regents-Style Questions:

1. What is the main purpose of mitosis?

   • A) Growth and tissue repair

   • B) Production of gametes

   • C) DNA replication

   • D) Crossing over

   • Answer: A) Growth and tissue repair

2. During which phase of meiosis does crossing over occur?

   • A) Metaphase I

   • B) Prophase I

   • C) Anaphase II

   • D) Telophase II

   • Answer: B) Prophase I

3. What is the result of meiosis?

   • A) Four haploid cells

   • B) Two diploid cells

   • C) Two haploid cells

   • D) Four diploid cells

   • Answer: A) Four haploid cells

Study Guide: Mitosis and Meiosis

Mitosis

• Definition: Mitosis is the process of cell division that results in two identical daughter cells, each with the same number of chromosomes as the parent cell.

• Phases of Mitosis:

  1. Prophase: "Prepare for division!" Chromatin condenses into chromosomes, and the nuclear envelope breaks down.

  2. Metaphase: "Middle line up!" Chromosomes line up at the cell's equatorial plane.

  3. Anaphase: "Away they go!" Sister chromatids are pulled apart towards opposite poles.

  4. Telophase: "Two nuclei form!" Nuclear envelopes reform around each set of chromosomes, which decondense back into chromatin.

  5. Cytokinesis: "Cut the cytoplasm!" The cytoplasm divides, resulting in two separate cells.

Meiosis

• Definition: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in four genetically different gametes (sperm or eggs).

• Phases of Meiosis (Meiosis I):

  1. Prophase I: "Pairs and cross!" Homologous chromosomes pair up to form tetrads, and crossing over occurs.

  2. Metaphase I: "Tetrads in the middle!" Tetrads align at the cell's equator.

  3. Anaphase I: "Apart they go!" Homologous chromosomes are pulled apart to opposite poles.

  4. Telophase I: "Two cells forming!" Nuclear envelopes may reform, and the cell divides (Cytokinesis).

  5. Result: Two haploid cells are formed; each has half the number of chromosomes as the original.

Key Differences Between Mitosis and Meiosis:

• Mitosis results in 2 identical cells; Meiosis results in 4 genetically varied gametes.

• Mitosis is for growth and repair; Meiosis is for sexual reproduction.

Simple Phrases to Remember:

• Mitosis: "Grow and Repair!"

• Meiosis: "Gametes for Sex!"

Regents-Style Questions:

1. What is the main purpose of mitosis?

   • A) Growth and tissue repair

   • B) Production of gametes

   • C) DNA replication

   • D) Crossing over

   • Answer: A) Growth and tissue repair

2. During which phase of meiosis does crossing over occur?

   • A) Metaphase I

   • B) Prophase I

   • C) Anaphase II

   • D) Telophase II

   • Answer: B) Prophase I

3. What is the result of meiosis?

   • A) Four haploid cells

   • B) Two diploid cells

   • C) Two haploid cells

   • D) Four diploid cells

   • Answer: A) Four haploid cells