Science

• Mitosis


  If a cell wants to make a duplicate of itself, it first must copy its DNA (part of a chromosome). The copies then must be separated & sorted into two sides of the cell. The cell then splits in two. Part of each parent is carried to the two new cells.
• MIT


  Makes It Two (diploid)
• Meiosis


  Has to do with sexual reproduction
• Mitosis


  Results in identical twins
• Meiosis


  Results in egg and sperm (haploid)
• Mitosis


  1. Interphase

  2. Prophase

  3. Metaphase

  4. Anaphase

  5. Telophase
• Interphase


  DNA is replicated along with organelles and other cellular components and the cell prepares for division
• Prophase


  • Chromosomes appear and are thickened and shortened
  • Spindle fibres form and centrioles go to opposite ends of the cell
  • Nucleolus disappears and nuclear membrane breaks down
• Metaphase


  • The chromosomes line up the middle of the cell
  • Spindle fibres attached to the centromere of each replicated chromosome
• Anaphase


  • The chromosomes split in the middle to form chromatids (half a chromosome)
  • Sister chromatids are pulled by the spindle fibres to opposite poles of the cell
• Telophase


  • The chromosomes, along with the cytoplasm and its organelles and membranes are divided into 2 daughter cells
  • Spindle disappears, nuclear membranes and nucleolus forms and centrioles divide
  • Chromosomes become thinner and longer
• Hand gestures for Mitosis

  1. Prophase – DNA condenses and is already duplicated

  2. Nuclear membrane dissolves

  3. Metaphase – chromosomes are positioned in the center of the cell and held together by the spindle fibres and centrioles

  4. Anaphase – chromosomes split into chromatids and get pulled to the ends of the cell by the spindle fibres. The cell divides into 2 cells and go back into their interphase structure
• Daughter cell


  A replication of the original cell (also called the mother cell)
• Homologous pair


  Pair of chromosomes. One coming from the father and the other from the mother
• Diploid


  A cell with the full number of chromosomes (46)
• Haploid


  A cell with half the number of chromosomes (23)
• Chromatid


  A copy of a chromosome joined at the center to the original chromosome
• Cytokinesis


  The actual splitting of the daughter cells into two separate cells, which occurs differently in plant and animal cells
• Meiosis


  A special process of nuclear division which results in the production of sperm or ova. Meiosis involves two divisions and results in four daughter cells, each containing only half the original number of chromosomes.
• Diploid chromosome number


  All human somatic (body) cells have 46 chromosomes
• Haploid chromosome number


  The sex cells, or gametes, have 23 chromosomes
• Meiosis avoids doubling the amount of DNA every time fertilisation occurs (slight variations in the amount of DNA can have a drastic effect on the phenotype)
• Meiosis


  1. Interphase

  2. Prophase I

  3. Metaphase I

  4. Anaphase I

  5. Telophase I & Cytokinesis

  6. Prophase II

  7. Metaphase II

  8. Anaphase II

  9. Telophase II & Cytokinesis
• Interphase


  • The chromosomes have replicated, and the chromatin begins to condense
• Prophase I


  • The chromosomes are completely condensed. The homologous chromosomes pair up with one another
• Metaphase I


  • The nuclear membrane dissolves and the homologous chromosomes attach to the spindle fibers. They are preparing to go to opposite poles.
• Anaphase I


  • The chromosomes move to opposite ends of the cell
• Telophase I & Cytokinesis

  • The cell begins to divide into two daughter cells. Each daughter cell can get any combination of maternal and paternal chromosomes.
• Prophase II


  • The cell has divided into two daughter cells.
• Metaphase II


  • The chromosomes line up on the spindle fibers.
• Anaphase II


  • The two cells each begin to divide. The chromosomes detach and the sister chromatids move to opposite ends of each cell.
• Telophase II & Cytokinesis


  • With the formation of four cells, meiosis is over. Each of these prospective cells carries half the number of chromosomes of somatic cells (23 chromosomes = haploid).
• Chromosome


  A structure in the cell nucleus that contains the genetic material
• Chromatid


  One of the two identical copies of a chromosome after DNA replication
• Chromatin


  The complex of DNA and proteins that makes up the contents of the cell nucleus
• Transcription


  The process of copying genetic information from DNA to RNA
• Translation


  The process of synthesizing proteins from the information encoded in mRNA
• Mitosis


  The process of cell division that results in two genetically identical daughter cells
• Meiosis


  The process of cell division that results in four genetically distinct daughter cells
• Mitosis and meiosis are both involved in making new cells