combined science bio

• Movement


  An action by an organism causing a change of position or place
• Respiration


  The chemical reactions in cells that break down nutrient molecules and release energy
• Sensitivity


  The ability to detect and respond to changes in the environment
• Growth


  A permanent increase in size
• Reproduction


  The processes that make more of the same kind of organism
• Excretion


  Removal from organisms of toxic materials and substances in excess of requirements
• Nutrition


  Taking in of materials for energy, growth and development
• Organisms are made of cells
• Plant cell


  • Cell wall
  • Nucleus
  • Cytoplasm
  • Chloroplasts
  • Vacuoles
  • Location of cell membrane
• Animal cell


  • Nucleus
  • Cytoplasm
  • Location of cell membrane
• Functions of structures seen under light microscope in plant and animal cells
• Calculating magnification and size of biological specimens

  Use millimetres as units
• Diffusion


  The net movement of particles from a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of their random movement
• Substances move into and out of cells by diffusion through the cell membrane
• Osmosis


  The net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane
• Water diffuses through partially permeable membranes by osmosis
• Water moves in and out of cells by osmosis through the cell membrane
• Specialised cells


  • Ciliated cells - movement of mucus
  • Root hair cells - absorption
  • Palisade mesophyll cells - photosynthesis
  • Red blood cells - transport of oxygen
  • Sperm and egg cells - reproduction
• Chemical elements that make up biological molecules

  • Carbon
  • Hydrogen
  • Oxygen
  • Nitrogen
• Monomers


  Smaller molecules from which larger molecules are made
• Polymers


  • Starch and glycogen from glucose
  • Proteins from amino acids
  • Fats and oils from fatty acids and glycerol
• Using chemical tests


  1. Iodine solution for starch

  2. Benedict's solution for reducing sugars

  3. Biuret test for proteins

  4. Ethanol emulsion test for fats and oils
• Water


  Important as a solvent
• Enzymes


  Proteins that function as biological catalysts
• Enzyme action


  Complementary shape of active site and substrate, formation of product
• As temperature increases


  Enzyme activity increases (due to kinetic energy, shape and fit, frequency of effective collisions) until denaturation occurs
• As pH changes


  Enzyme activity changes (due to shape and fit and denaturation)
• Photosynthesis


  The process by which plants manufacture carbohydrates from raw materials using energy from light
• Word equation for photosynthesis

  Carbon dioxide + water → glucose + oxygen (in the presence of light and chlorophyll)
• Leaf structures


  • Chloroplasts
  • Cuticle
  • Guard cells
  • Stomata
  • Upper epidermis
  • Lower epidermis
  • Palisade mesophyll
  • Spongy mesophyll
  • Vascular bundles
  • Xylem
  • Phloem
• Balanced equation for photosynthesis

  6CO2 + 6H2O → C6H12O6 + 6O2
• Chlorophyll


  Transfers light energy into chemical energy in molecules, for the synthesis of carbohydrates
• Leaf features and functions

  • Palisade mesophyll and chloroplasts - photosynthesis
  • Stomata, spongy mesophyll cells and guard cells - gas exchange
  • Xylem - transport and support
  • Phloem - transport
• Nitrate ion and magnesium ion deficiency

  Effects plant growth
• Balanced diet


  For humans
• Principal sources and dietary importance

  • Carbohydrates
  • Fats
  • Proteins
  • Vitamins (C and D)
  • Mineral salts (calcium and iron)
  • Fibre (roughage)
  • Water
• Dietary needs


  Affected by age, gender, activity, pregnancy, breastfeeding
• Effects of malnutrition
• Causes and effects of vitamin D and iron deficiencies
• Ingestion


  The taking of substances, e.g. food and drink, into the body through the mouth