Cell division

• Cell Cycle


  The cycle of cellular development and division that occurs repeatedly throughout an organism's life
• Phases of the cell cycle

  • Interphase. Metaphase
• Stages of Interphase


  • Gap 1 (G1) phase
  • Synthesis (S) phase
  • Gap 2 (G2) phase
• Gap 1 (G1) phase


  • Cell rapidly grows, Ribonucleic acid (RNA) and proteins are created, DNA is copied
• Synthesis (S) phase


  • DNA is replicated, A sister chromatid is produced
• Gap 2 (G2) phase


  • Cell continues to produce RNA and proteins, The nucleus is prepared for division, Microtubules are being created to move the chromosomes during division
• Checkpoint


  • Identifies and fixes errors during vital processes like DNA replication or chromosome segregation, Causes cell cycle halt until errors are corrected
• Mitosis


  A type of cell division in which the parent cell divides to produce two new cells that are genetically identical to itself
• Meiosis


  A type of cell division that produces gametes (sperm and egg cells) with half the normal number of chromosomes
• Stages of Mitosis


  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
  • Cytokinesis
• Stages of Meiosis I

  • Prophase I
  • Metaphase I
  • Anaphase I
  • Telophase I
• Chromosomes do not replicate between Meiosis I and Meiosis II
• Cell cycle

  Cycle of cellular development and division that occurs repeatedly throughout an organism's life
• Interphase

  1. Gap 1 (G1) phase

  2. Synthesis (S) phase

  3. Gap 2 (G2) phase
• Interphase


  • Cell does not divide during this stage; instead, it merely grows
• Gap 1 (G1) phase


  Period of cell's development where it rapidly grows; Ribonucleic acid (RNA) and proteins are created for the creation of DNA

  
• Synthesis (S) phase


  Deoxyribonucleic Acid (DNA) of a cell is copied during this period; Chromosomes are replicated; Sister chromatid is a produced strand of a double-stranded chromosome
• Gap 2 (G2) phase


  Period during which the cell continues to produce RNA and proteins while also growing in size; Nucleus is being prepared for division; Microtubules are being created to move the chromosomes during division

  
• Checkpoints


  Important parts of the control system that identify errors during vital processes like DNA replication or chromosomal segregation and cause a cell cycle halt until the errors are corrected
• 1. Phase


  Cell division phase; Mitosis and meiosis are the two types of cell division in eukaryotic cells

  
• G0 state


  Arrested or quiescent stage where some cells may enter after division; Nerve cells, blood cells, and the majority of muscle cells remain in this state
• Mitosis


  1. Prophase

  2. Metaphase

  3. Anaphase

  4. Telophase

  5. Cytokinesis

  
• Mitosis


  Type of cell division in which one cell (the parent) divides to produce two new cells (the daughters) that are genetically identical to itself; The two daughter cells have the same number of chromosomes as the parent cell or diploid (2n)

  
• Meiosis


  Special type of cell division where the cell undergoes two stages of division to produce four daughter cells; Each daughter cell receives half the chromosome number, haploid(n), as the original parent cell with a unique set of genetic material
• Meiosis I


  1. Prophase I

  2. Metaphase I

  3. Anaphase I

  4. Telophase I

  
• Cell division by cleavage furrow formation

  1. Cleavage furrow forms

  2. Separates the two daughter cells
• Mitosis is a process where the cell undergoes division to produce two daughter cells with the same genetic material as the parent cell
• Stages of mitosis


  1. Prophase

  2. Metaphase

  3. Anaphase

  4. Telophase

  
• Meiosis


  1. Meiosis I

  2. Meiosis II
• Meiosis


  • Cell undergoes two stages of division
  • Produces four daughter cells
  • Each daughter cell receives half the chromosome number, haploid(n), as the original parent cell
  • With a unique set of genetic material
• Prophase I


  • Leptotene: Chromosomes condense, become sister chromatids
  • Zygotene: Homologous chromosomes pair up
  • Pachytene: Crossing-over occurs
  • Diplotene: Chromosomes begin to uncoil
  • Diakinesis: Paired chromosomes disperse in the nucleus
• Metaphase I


  Pairs of homologous chromosomes move to the equator of the cell

  
• Anaphase I


  Homologous chromosomes separate, each still composed of two chromatids
• Telophase I


  Individual chromosomes gather at the cell's poles, one from each pair of homologous chromosomes present in both poles, cytoplasm divides resulting in two new cells
• Meiosis II


  1. Prophase II

  2. Metaphase II

  3. Anaphase II

  4. Telophase II
• Prophase II


  New spindle forms, chromosomes condense
• Metaphase II


  Spindle fibers align the chromosomes along the equator
• Anaphase II


  Sister chromatids separate and move to opposite poles of the cell
• Telophase II


  Nuclear membrane reappears, spindle disintegrates, cell undergoes cytokinesis, meiosis produces four haploid cells

  
• Mitosis

  Helps an organism grow by making new cells