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Cell Division

Published on Nov 22, 2015

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PRESENTATION OUTLINE

LIFE CYCLE OF A CELL

  • Reproduction is essential
  • There is sexual and asexual

CELL CYCLE

  • Interphase
  • Can be divided into :
  • G1
  • S
  • G2

G1

  • RNA synthesis and protein synthesis
  • DNA replication and cell growth

S

  • Chromosomes double in number
  • Chromosomes get sister chromatid
  • The chromatids are connected by adhesive proteins
  • This connection includes a distinct structure called the centromere

G2

  • The building blocks for organelles are made in g1
  • The organelles are assembled in G2

MITOSIS

  • Divided into four stages:
  • Prophase
  • Metaphase
  • Anaphase
  • Telophase

PROPHASE

  • Sister chromatids slowly condense after replication
  • During prophase chromatids are joined at the centromere
  • In the nucleus nucleoli begin to disassemble
  • Centrosomes near the nucleus begin to go to opposite sides of the cell

METAPHASE

  • Chromosomes line up in the middle of the cell
  • Microtubles continue to grow extending the length of the cell

ANAPHASE

  • Splitting of the centromere
  • Sister chromatids separate, making individual chromosomes
  • Each sides of the cell have equal number of chromosomes
  • Microtubles continue growing making the cell bigger

TELOPHASE

  • Reverse of prophase
  • Restores cell to original functions
  • Chromosomes unwind and disperse
  • Nuclelio reassembles
  • Nuclear envelope reforms

CYTOKINESIS

  • Cell divides

MEIOSIS 1

  • Prophase
  • Metaphase
  • Anaphase
  • Telophase

PROPHASE 1

  • Homologous chromosomes pair up in an X
  • The x pairing is called a tetrad
  • Certain genes are exchanged between mom and dad
  • Other cytoplasmic events that occur in mitosis occur in meiosis

METAPHASE 1

  • Tetrads line up in the middle of cell
  • Creates a chance for genetic diversity

ANAPHASE

  • Homologous chromosomes separate
  • Move to opposite poles of the cell

TELOPHASE AND CYTOKINESIS

  • Relocation of chromosomes with sister chromatids
  • Chromosomes partially de-condense
  • No chromosome replication occurs before the two daughter cells move to meiosis 2

MEIOSIS 2

  • Separates sister chromatids
  • Sister chromatids are not genetically identical because of meiosis 1

PROPHASE 2

  • Spindle fiber attaches to the sister chromatids

METAPHASE 2

  • Sister chromatids align in the middle of the cell