Mitosis and meiosis

• Purpose of mitosis


  For growth and repair
• Mitosis


  • Produces diploid cells
• Purpose of meiosis


  To produce gametes (sperm and egg)
• Mitosis


  • Daughter cells have same amount of DNA as parent cell
• Mitosisand Meiosis 


  A type of cell division
• Meiosis


  • Produces haploid cells
• Meiosis


  • Produces genetically different daughter cells
• Mitosis


  • Produces new cells
  • Produces genetically identical daughter cells
• Meiosis


  • Daughter cells have half the amount of DNA as parent cell
• Mitosis

  Both have the purpose of growth and repair
• Mitosis


  1. Continuous process of cell division

  2. Involves four basic processes: prophase, metaphase, anaphase, telophase

  3. Division of the cell nucleus

  4. Nucleur membrane is broken

  5. Chromatids of the centromere separate

  6. Nuclear membrane rebuilds around daughter cells

  7. Each daughter cell is identical
• Meiosis


  1. Division of a cell into four genetically different daughter cells

  2. Involves two rounds of cell division

  3. Produces gametes (sperm and egg cells)

  4. Reduces the chromosome number by half
• Similarities between mitosis and meiosis

  • Both take place in the cell nucleus
  • Both involve cell division
  • Both have an M-phase with metaphase and anaphase
  • Both involve DNA synthesis
• The difference between mitosis and meiosis is quite apparent. They are two very different processes that have two different functions.
• Mitosis


  Used for the growth and development of cells
• Meiosis


  • Required for genetic diversity and continuity of all living organisms
  • Plays an important role in the repair of genetic defects in gametes
• Interphase is divided into 3 phases: G1, S(synthesis) and G2
• G1 (1st gap) - small cell is absorbing nutrients growing and doing its job
• S (synthesis) - cell is continuing to grow and duplicates its dna
• A single copied chromosome is called a chromatid
• The four phases of mitosis are prophase metaphase anaphase and telophase
• Prophase

  • chromosomes can be seen as two chromatids in the shape of an x
  • Nuclear envelope dissolves
• Metaphase

  • Chromosomes line up in the middle of the cell
• Anaphase

  • third phase of mitosis. Spindle fibers pull chromosomes toward the separate poles
  • chromosomes are split in half
  • sister chromatids are now their own chromosomes
• Telophase

  • final stage of mitosis
  • The nuclear envelope reforms around each set of chromosomes and chromosomes straighten out
  • Spindle fibers are gone
• Cytokinesis

  • Final step in the cell cycle
  • Actually means "cell moving"
• Steps in cell cycle

  • Interphase
  • Metaphase
  • Cytokinesis
• Crossing-over occurs during: prophase 1
• produced during meiosis in the ovary? 4 haploid ova
• What are produced during meiosis in the testes? 4 haploid sperms
• How many chromosomes will be found in each of the 4 new cells formed as a result of meiotic cell division? only one-half as many chromosomes as the parent cell
• These event occur only during meiosis

  • The homologous chromosomes pair up
• There are 64 chromosomes in a fern plant. After mitosis, each daughter cell formed will have how many chromosomes?

  • 64
• Humans have diploid chromosome number (2N) which is equal to 46 chromosomes. What is the chromosome number of each daughter cell produced during meiosis?

  - 23
• Which of the following is true about interphase? I. Cell growth occurs. II. Chromosome duplicate. III. Nuclear division occurs. IV. DNA synthesis happens.

  • I, II and IV
• a pair of chromosomes that are similar in length as well as gene and centromere position - homologous chromosomes
• a process in which homologous chromosomes pair up and exchange genetic material - meiosis
• Controls the activities of the cell including cell division - nucleus
• Long and thread-like DNA in a non-dividing cell - chromatin
• Cell cycle -  series of events cells go through as they grow and divide