B1- Chromosomes and Mitosis

• Why do cells need to divide?

  To survive and grow
• What do chromosomes contain?

  Genetic information
• What is the structure of chromosomes?

  Coiled-up lengths of DNA molecules
• What do different genes control?

  The development of different characteristics
• How many copies of each chromosome do body cells normally have?

  Two copies
• From whom do organisms inherit their chromosomes?

  One from the mother and one from the father
• How many pairs of chromosomes do humans have?

  23 pairs
• What is the purpose of the cell cycle?

  To produce new cells for growth, development, and repair
• What is the stage of the cell cycle when the cell divides called?

  Mitosis
• How do multicellular organisms use mitosis?

  To grow or replace damaged cells
• What is the result of the cell cycle?

  Two new cells identical to the original cell
• What are the two main stages of the cell cycle?

  1. Growth & DNA Replication
  2. Mitosis
• What happens to DNA in a cell that is not dividing?

  It is spread out in long strings
• What must a cell do before it divides?

  Grow and increase the amount of subcellular structures
• What happens to DNA before cell division?

  It duplicates to form X-shaped chromosomes
• What do the arms of the X-shaped chromosomes represent?

  Exact duplicates of each other
• What occurs during mitosis?

  The chromosomes line up at the center and are pulled apart
• What forms around each set of chromosomes after mitosis?


  Membranes that become the nuclei of the new cells
• What happens to the cytoplasm and cell membrane after mitosis?

  They divide
• What is the result of mitosis in terms of daughter cells?

  Two new daughter cells that are identical
• How does the DNA of daughter cells compare to the parent cell?

  It is identical