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9th Grade Cellular reproduction

Chromosomes are condensed DNA.

  • The Centromere is part of chromosome where sister chromatids are held together.

  • 1chromosome = 2 chromatids

MITOSIS (ASEXUAL REPRODUCTION)

  • Mitosis’s function is to grow and repair/maintain body.

    • A cell grows, and divides, and repeats during its life.

  • 1 parent cell (46 chromosomes) produces 2 identical daughter cells (46 chromosomes each).

  • Your cells do not divide (perform mitosis) continually. Most of the time, they are in interphase.

  • Cancer is when cells uncontrollably divide.

INTERPHASE (PRE MITOSIS)

  • The cell grows in size and performs regular functions.

  • Chromosomes are replicated (doubled).

FOUR STAGES OF MITOSIS

  • PMAT : Prophase, Metaphase, Anaphase, Telophase

  • Prophase

    • Centrioles (poles) appear and move to opposite ends of cell.

    • Spindle fibers form between the poles.

  • Metaphase

    • Chromatids line up in the middle of the cell and attach to the spindle fibers.

  • Anaphase

    • Chromatids separate and begin to move to opposite ends of of the cell.

  • Telophase

    • Two new nuclei form and the chromosomes appear as chromatin (threads rather than rods).

    • Mitosis ends.

Cytokinesis

  • Cell membrane moves inward to create two daughter cells (each with its own nucleus and identical chromosomes).

MEIOSIS (SEXUAL REPRODUCTION)

  • Prophase 1

    • Chromosomes line up with their homologous pairs.

      • Homologous chromosomes are 2 chromosomes that are about the same size & have the same gene type in the same place.

    • Crossing over occurs (homologous pairs transfer their genetic info, creating recombinant chromosomes).

  • Metaphase 1

    • Chromosomes line up in the middle of the cell in pairs and attach to spindle fibers.

  • Anaphase 1

    • The spindle fibers pull the homologous chromosomes apart and they move to opposite ends of the cell.

  • Telophase 1 and Cytokinesis (ends meiosis one)

    • The nuclear membranes reform around the chromosomes, the two cells are separate.

  • Prophase 2

    • The two haploid cells start to go through meiosis 2.

    • The cells nuclear membrane breaks back down, and spindle fibers begin to form.

  • Metaphase 2

    • Chromosomes line up in the middle of the cell and attach to spindle fibers (single file).

  • Anaphase 2

    • Sister chromatids separate and are pulled to opposite sides of the cell by spindle fibers.

  • Telophase 2 and Cytokinesis

    • The nuclear membranes reforms.

    • Four new haploid cells (23 chromosomes) have formed!

    • These cells are gametes, and each one is unique and different from each other (NO identical cells, unlike cells from mitosis).

  • Nondisjunction occurs when chromosomes don't separate correctly.

    • A cell may receive too many or too little chromosomes in the separation.







Chromosomes are condensed DNA.

  • The Centromere is part of chromosome where sister chromatids are held together.

  • 1chromosome = 2 chromatids

MITOSIS (ASEXUAL REPRODUCTION)

  • Mitosis’s function is to grow and repair/maintain body.

    • A cell grows, and divides, and repeats during its life.

  • 1 parent cell (46 chromosomes) produces 2 identical daughter cells (46 chromosomes each).

  • Your cells do not divide (perform mitosis) continually. Most of the time, they are in interphase.

  • Cancer is when cells uncontrollably divide.

INTERPHASE (PRE MITOSIS)

  • The cell grows in size and performs regular functions.

  • Chromosomes are replicated (doubled).

FOUR STAGES OF MITOSIS

  • PMAT : Prophase, Metaphase, Anaphase, Telophase

  • Prophase

    • Centrioles (poles) appear and move to opposite ends of cell.

    • Spindle fibers form between the poles.

  • Metaphase

    • Chromatids line up in the middle of the cell and attach to the spindle fibers.

  • Anaphase

    • Chromatids separate and begin to move to opposite ends of of the cell.

  • Telophase

    • Two new nuclei form and the chromosomes appear as chromatin (threads rather than rods).

    • Mitosis ends.

Cytokinesis

  • Cell membrane moves inward to create two daughter cells (each with its own nucleus and identical chromosomes).

MEIOSIS (SEXUAL REPRODUCTION)

  • Prophase 1

    • Chromosomes line up with their homologous pairs.

      • Homologous chromosomes are 2 chromosomes that are about the same size & have the same gene type in the same place.

    • Crossing over occurs (homologous pairs transfer their genetic info, creating recombinant chromosomes).

  • Metaphase 1

    • Chromosomes line up in the middle of the cell in pairs and attach to spindle fibers.

  • Anaphase 1

    • The spindle fibers pull the homologous chromosomes apart and they move to opposite ends of the cell.

  • Telophase 1 and Cytokinesis (ends meiosis one)

    • The nuclear membranes reform around the chromosomes, the two cells are separate.

  • Prophase 2

    • The two haploid cells start to go through meiosis 2.

    • The cells nuclear membrane breaks back down, and spindle fibers begin to form.

  • Metaphase 2

    • Chromosomes line up in the middle of the cell and attach to spindle fibers (single file).

  • Anaphase 2

    • Sister chromatids separate and are pulled to opposite sides of the cell by spindle fibers.

  • Telophase 2 and Cytokinesis

    • The nuclear membranes reforms.

    • Four new haploid cells (23 chromosomes) have formed!

    • These cells are gametes, and each one is unique and different from each other (NO identical cells, unlike cells from mitosis).

  • Nondisjunction occurs when chromosomes don't separate correctly.

    • A cell may receive too many or too little chromosomes in the separation.