Cell division

• Define Mitosis

  A form of cell division that produces identical daughter cells for growth and sexual reproduction
• Mitosis does not give rise to genetic variation
• What does the Cell cycle achieve

  1. Cell forms

  2. Cell grows

  3. Cell divides to form daughter cells
• Cell cycle has…


  • Has three stages
  • Is controlled by checkpoints
• What are the 4 stages of Mitosis

  1. Prophase

  2. Metaphase

  3. Anaphase

  4. Telophase
• Cytokinesis


  1. Parent and replicated organelles move to opposite sides of the cell

  2. Cytoplasm divides to produce two new cells
• Interphase


  1. Cell grows

  2. Chromosomes and some organelles are replicated

  3. Chromosomes begin to condense
• Prophase


  1. Nuclear envelope breaks down

  2. Chromosomes condense

  3. Centricles move to opposite poles
• Metaphase

  Chromosomes move to the equator and attach to spindle fibres
• Anaphase


  Sister chromatids are separated
• Telophase

  1. Nuclear envelope reforms

  2. Spindle is broken down
• Meiosis


  A form of cell division that gives rise to genetic variation by producing haploid gametes
• Meiosis

  • Crossing over of chromatids
  • Independent assortment of chromosomes
• Meiosis I


  1. Prophase I

  2. Metaphase I

  3. Anaphase I

  4. Telophase I
• What are the 4 stages of Meiosis II

  1. Prophase II

  2. Metaphase II

  3. Anaphase II

  4. Telophase II
• What is a Tissue?

  Groups of cells that perform a common function
• What are the 2 types of plant Tissues

  • Xylem
  • Phloem
• Organ definition

  Groups of tissues that work together to perform a wider function
• Organ systems

  Groups of organs that work together to perform an essential life function
• Xylem

  • Transport water and minerals
  • Provide structural support
  • Made of dead cells with open ends
  • Thickened with lignin
• Phloem

  • Involved in translocation of food substances and nutrients
  • Made of living cells that form long tubes with perforated sieve plates
• Epithelial tissue

  • Squamous - smooth, flat, thin cells that line surfaces
  • Ciliated - column-shaped cells with cilia that line structures like trachea and oviducts
• Connective tissue

  • Provides support and holds structures together
• Muscle tissue

  • Specialised for movement through contraction
• Nervous tissue

  • Specialised for impulse conduction
• Stem cells


  Undifferentiated cells that can develop into any cell type
• What are Stem cellsused in?

  • Used in research and medicine for tissue repair, treatment of disorders, and studying development
• Differentiation

  The process by which a cell specialises to carry out a particular function
• Stem cell differentiation examples

  • Erythrocytes (red blood cells)
  • Neutrophils (white blood cells)
• Plants retain ability to differentiate into different cell types throughout their life
• Plant cell division

  • Occurs at a high rate in meristems
  • Dividing meristem cells are the cambium which give rise to xylem and phloem
• Sperm cells

  Male gametes adapted to reach, penetrate and fertilise the ovum (female gamete)