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• Characteristics of living organisms

  • They respire
  • They move
  • They reproduce
  • They grow and develop
  • They excrete their waste
  • They require nutrition
  • They control their internal conditions (e.g. body temperature, blood pressure, osmoregulation)
  • They respond to their surroundings
• Five kingdoms of living organisms

  • Plants
  • Animals
  • Fungi
  • Protoctists
  • Prokaryotes

  
• Plants


  • Multicellular organisms
  • Cells contain chloroplasts, allowing photosynthesis
  • Cell walls made of cellulose
  • Store carbohydrates as starch or sucrose
• Animals


  • Multicellular organisms
  • Cells do not contain chloroplasts, cannot perform photosynthesis
  • Acquire nutrition by feeding on other plants and animals
  • Cells do not have cell walls
  • Movement involves nervous coordination
  • Store carbohydrates as glycogen
• Fungi


  • Can be multicellular or unicellular
  • Cannot carry out photosynthesis due to lack of chloroplasts
  • Body organised into mycelium of fungal hyphae
  • Hyphae not divided into individual cells
  • Cell walls made of chitin
  • Feed by extracellular secretion of digestive enzymes and absorption
  • May store carbohydrates as glycogen
• Protoctists


  • Mostly microscopic single-celled organisms
  • Some have animal-like features (protozoa), others have plant-like features (algae)
  • Some are pathogenic, like Plasmodium causing malaria
• Prokaryotes


  • Primary form is bacteria
  • Single-celled, no nucleus
  • Smaller than eukaryotic cells
  • Nuclear material in cytoplasm, DNA in single circular chromosome
  • Cell wall made of peptidoglycan
  • Some have slime layer or capsule
  • Some have flagella for swimming
  • Many have plasmids
• Pathogens


  Microorganisms that cause diseases in other organisms
• Viruses


  • Parasites that can only reproduce in a host
  • Smaller than bacteria
  • No cellular structure, only genetic material (DNA or RNA) surrounded by protein coat
  • Not living organisms as they don't carry out all life processes
  • Can infect every type of living organism
  • Wide variety of shapes
• Examples of viruses


  • Tobacco mosaic virus
  • Influenza virus
  • HIV
• Organelle


  Part of a cell with a specific function
• Cell


  The basic structural unit of all living organisms
• Tissue


  A group of cells that work together to perform a specific function
• Organ


  A group of tissues that work together to perform a specific function
• Organ System


  A group of organs that work together to perform a specific function
• Structures present in both plant and animal cells

  • Nucleus
  • Cytoplasm
  • Cell membrane
  • Mitochondria
  • Ribosomes
• Structures present only in plant cells, not animal cells


  • Cell wall
  • Permanent cell vacuole
  • Chloroplasts
• Cell Differentiation


  The process by which a cell specializes under the control of genes
• Embryonic stem cells


  Found in early development of embryo, can differentiate into any cell type
• Adult stem cells


  Found in specific adult tissues, can specialize into certain cell types but not any type
• Stem cell therapy


  Using stem cells to treat or repair damaged tissues
• Macromolecules in the body

  • Carbohydrates
  • Proteins
  • Lipids
• Carbohydrates


  Main source for supplying body cells with energy, made up of carbon, hydrogen and oxygen
• Types of carbohydrates


  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides


  • Glucose
  • Fructose
• Disaccharides


  • Sucrose
  • Lactose
  • Maltose
• Polysaccharides


  • Starch
  • Glycogen
  • Cellulose
• Proteins


  Made up of carbon, hydrogen, oxygen, nitrogen and sometimes sulfur, needed for growth and repair of tissues
• Amino acids


  The building blocks for proteins
• Enzymes


  Biological catalysts that speed up reaction rates without being consumed
• Lock and key theory

  Substrates collide with the active site of enzymes and will only bind if the active site is complementary
• Factors affecting enzyme activity

  • Enzyme concentration
  • Substrate concentration
  • Temperature
  • pH
• Lipids


  Consist of carbon, hydrogen and oxygen, with glycerol and fatty acids as building blocks
• Diffusion


  Movement of substances from high to low concentration, down a concentration gradient
• Osmosis


  Movement of free water molecules from high to low water potential across a semi-permeable membrane
• Active transport


  Movement of molecules from low to high concentration against a concentration gradient, using ATP
• Factors affecting rate of movement in and out of cells

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


  Process by which plants use light energy, trapped by chlorophyll, to convert carbon dioxide and water into glucose

  
• Factors affecting photosynthesis


  • Light intensity
  • Carbon dioxide concentration
  • Temperature

  
• Minerals required for plant growth

  • Nitrate
  • Magnesium
  • Potassium
  • Phosphate