section 1 - nature and variety of living organisms

• Characteristics of living organisms


  • Movement
  • Respiration
  • Sensitivity
  • Growth
  • Reproduction
  • Excretion
  • Nutrition
  • Control
• Movement


  Get from a to b
• Movement


  • Tiger running
• Respiration


  Release of energy in cells
• Respiration


  • Humans exercise
• Sensitivity


  Responding to surrounding
• Sensitivity


  • Plants grow towards light
• Growth


  Increase in number of cells
• Growth


  • Kitten to cat
• Reproduction


  Production of offspring
• Reproduction


  • Dogs having puppies
• Excretion


  Removal of metabolic waste
• Excretion


  • Urination
• Nutrition


  Gaining food
• Nutrition


  • Photosynthesis
• Control


  Maintaining internal conditions
• Control


  • Body temperature 37C
• Levels of organization


  • Organelle
  • Cell
  • Tissue
  • Organ
  • Organ system
• Levels of organization


  • Nucleus
  • RBC
  • Xylem
  • Lung
  • Digestive system
• Tissue


  A group of similar cells that work together to carry out a function
• Specialised cells


  Can carry out a particular function
• Cell differentiation


  Changed a cell to become specialised
• Stem cells


  Undifferentiated cells waiting to be specialized
• Stem cells


  • Found in the bone marrow (adults) and embryo
• Stem cells may be used to cure disease by replacing diseased cells with healthy ones
• Stem cells can also be used to make organs in a lab but this could lead to contamination with a virus
• People are against the use of embryonic stem cells as they have potential to be a human life and can not give consent
• Cell types


  • Animal cell
  • Plant cell
  • Bacteria
• Cell features


  • Photosynthesis
  • Multicellular
  • Cell walls
  • Store carbohydrate as glycogen
  • Store carbohydrate as starch/sucrose
  • Plasmid
  • Cytoplasm
  • Nucleus (Eukaryotic)
  • Can be pathogenic
  • Chloroplast
  • Protein coat
• Animal cell


  • Dog
• Plant cell


  • Rose
• Fungi


  • Unicellular eg fungi
  • Multicellular mucor
• Bacteria


  • Pneumococcus
• Virus


  • HIV causes aids
• Protoctist


  • Like animal eg amoeba
  • Like plant eg chlorella
• Diffusion


  Movement of particles from a high concentration to a low concentration across a semi-permeable membrane, passive process
• Osmosis


  Movement of water from a high water concentration to a low water concentration across a semi-permeable membrane, passive process
• Active transport


  Movement of particles from a low concentration to a high concentration across a semi-permeable membrane, active process
• Factors affecting rate of cell movement


  • Distance
  • Concentration gradient
  • Temperature
  • Surface area to volume ratio
• Distance


  The shorter the distance the quicker diffusion