mitosis and meiosis

• From what do all cells develop?

  Pre-existing cells
• What are chromosomes made of?

  DNA and protein
• What is the structure of chromosomes when a cell is not dividing?

  They are in long, thin thread-like structures called chromatin
• What are genes?

  Units of inheritance
• What is the haploid number of chromosomes in humans?

  23 chromosomes
• How are haploid cells symbolized?

  By the letter 'n'
• What type of cells are haploid in humans?

  Eggs and sperm
• What is the diploid number for humans?

  46 chromosomes
• How are diploid cells symbolized?

  By '2n'
• What is the origin of chromosomes in diploid cells?

  One chromosome is derived from the mother and the other from the father
• What are the two main phases of the cell cycle?

  Interphase and Mitosis
• What occurs during interphase?

  The cell is not dividing
• What is mitosis?

  A form of nuclear division that produces two identical daughter nuclei
• In what type of cells does mitosis take place?

  In non-reproductive cells, known as somatic cells
• How many stages are there in mitosis?

  Four stages
• What are the four stages of mitosis?

  1. Prophase
  2. Metaphase
  3. Anaphase
  4. Telophase
• What happens during prophase?

  The nuclear membrane breaks down and chromosomes become visible
• What occurs during metaphase?

  The chromosomes line up along the equator of the cell
• What is the shortest phase in mitosis?

  Anaphase
• What happens during telophase?

  The chromosomes lengthen to form chromatin and the nuclear membrane forms around each chromatin
• What follows immediately after mitosis?

  Cell division
• What is the process of cell division in animals called?

  Cleavage furrow
• What are the functions of mitosis in unicellular and multicellular organisms?

  • Unicellular: Reproduction
  • Multicellular: Growth and Repair
• What is meiosis?

  A nuclear division that produces four haploid un-identical daughter cells
• What is the function of meiosis?

  To halve the number of chromosomes to produce gametes for sexual reproduction
• Where does meiosis occur in females?

  In the ovary
• Where does meiosis occur in males?

  In the testis
• Compare mitosis and meiosis.

  Mitosis:

  • Produces 2 identical daughter cells
  • Same number of chromosomes as parent cell

  
  

  Meiosis:

  • Produces 4 non-identical daughter cells
  • Daughter cells are haploid (half the number of chromosomes of parent)
• What is cancer?

  Cells that have lost the ability to control the rate of mitosis
• What are the two types of cancer?

  1. Benign tumours (non-life threatening)
  2. Malignant tumours (life threatening)
• What are carcinogens?

  Substances that cause cancer
• Name two examples of carcinogens.

  1. UV radiation
  2. Cigarette smoke
• How many daughter cells does mitosis produce?

  Two daughter cells
• How many daughter cells does meiosis produce?

  Four daughter cells
• What is the difference in chromosome number between daughter cells produced by mitosis and meiosis?

  Mitosis produces the same number of chromosomes as the parent cell, while meiosis produces haploid daughter cells
• What stage represents the largest part of mitosis?

  Interphase
• Define mitosis.

  Cells dividing into two identical daughter cells
• State two ways in which meiosis differs from mitosis.

  Meiosis produces 4 non-identical daughter cells, while mitosis produces 2 identical daughter cells
• Explain the term cancer.

  Cancer is an uncontrolled rate of mitosis
• Explain the term diploid.

  Two of each chromosome