Cells & Structures (T1Y9)

• Nucleus


  Controls the activities of the cell
• Mitochondrion


  Where aerobic respiration occurs
• Ribosomes


  Where proteins are made
• Cytoplasm


  Part of the cell where most chemical reactions take place
• Cell membrane


  Controls the movement of substances in and out of the cell
• Cytoplasm is where anaerobic respiration occurs
• Ribosomes are larger than mitochondria


  False
• All animal cells have a nucleus


  False
• DNA


  Molecule of heredity found inside the nucleus
• Levels of Organisation


  • Cell
  • Tissue
  • Organ
  • System
• Six Systems of the Body

  • Reproductive
  • Digestive
  • Circulatory
  • Nervous
  • Excretory
  • Respiratory
• Nervous tissue


  For carrying messages
• Muscle tissue


  For contraction
• Specialised cells have a structure related to their function
• Differentiation


  When cells become specialised
• Specialisation


  Cells are adapted to specific functions
• Sperm cell


  • Cilia
• Red blood cells


  • No nucleus
• Nerve cell


  • Cytoplasm
• Muscle cell


  • Nucleus
  • Cytoplasm
• White blood cells


  • Engulfing bacteria
• Xylem


  Transports water
• Phloem


  Transports dissolved sugars
• Xylem cells


  • Strong, hollow, dead cells that form continuous tubes
• Root hair cells


  • Large surface area to absorb water
• Palisade cells


  • Packed with chloroplasts, large surface area
• Guard cells


  • Control the opening and closing of stomata
• Human egg cell


  • Cell membrane
  • Cytoplasm
  • Jelly layer
  • Nucleus
• Cell differentiation


  Cells adapted for a particular function (job)
• Differentiation


  When a cell becomes specialised
• Stem cells


  Cells that can become different cell types
• As a cell differentiates it becomes specialized
• Meristem cells


  Plant cells that can keep dividing throughout the life of a plant
• Stem cells


  Undifferentiated cells that can produce many cells types
• 1 stem cell


  4 specialized cells
• Adult stem cells


  Rare and found at certain locations only
• Places where adult stem cells are found

  • Bone marrow
  • Skin
  • Muscle
• Adult stem cells


  • Can differentiate only into cells from the type of tissue where they are found
  • Role is to replace body cells that die through injury and disease
• Bone marrow stem cells

  Develop into red blood cells, white blood cells and platelets