Biology

• 7 characteristics of life


  • Growth
  • Movement
  • Interaction
  • Excretion
  • Reproduction
  • Nutrition
  • Respiration
• Cell


  • Simplest collection of matter that can be alive, smaller than cell not alive
  • Basic unit of structure and function
  • All cells come from other cells
• To see a cell we need a microscope
• Electron microscope is used to see organelles
• Subcellular structure can be magnified up to 500,000 times
• Organism


  • Unicellular (lone-celled)
  • Multicellular (many-celled)
• The size and weight of a multicellular organism depends mostly on the number of cells, not on the size of the cell
• The nucleus controls all activities within the cell.
• Meiosis is the process by which sex cells (gametes) are produced through cell division.
• Chromosomes are made up of genes that contain instructions for making proteins.
• Cell membrane - regulates what enters/exits the cell
• DNA contains genetic information that determines how an organism develops and functions.
• Nutrition


  The process by which the cells take in the food they need to survive
• Each living organism needs specific nutrients
• Nutrients can be used for


  • Building
  • Repairing
  • Maintaining the body
  • Getting energy
• Types of nutrients


  • Inorganic
  • Organic
• Inorganic nutrients


  Cannot be used for energy, substances involved in chemical reaction, Water, minerals, gases
• Organic nutrients


  For energy, produced by living organisms, proteins, fats, carbohydrates, fibre for animal
• Autotrophic organisms


  Produce their own food, called primary producers
• Autotrophic organisms


  • Plants
  • Some bacteria
• Convert inorganic to organic with

  1. high value

  2. LIGHT ENERGY
• Photosynthesis


  Converts solar energy into chemical energy
• Chemosynthesis


  Converts inorganic to organic
• Autotrophs


  Perform photosynthesis
• Photosynthesis


  1. Sunlight

  2. CO₂+H2O

  3. C6H12O6 +02

  4. glucose
• Chloroplast


  • Leaf cell
  • Site of photosynthesis
• Stomata


  • Bottom of leaf
  • Let's out O2, absorbs CO2
  • Opens when water available, closes when not
• All plants can reproduce sexually
• Sexual reproduction normally takes place in the flower where the seed is
• Spermatophytes


  Plants where sexual reproduction takes place in the flower
• Classification of plants that reproduce sexually

  • Hermaphroditic
  • Dioecious
• Hermaphroditic plants


  • Have male and female reproductive organs in the same flower
• Dioecious plants


  • Have separate male and female flowers on different plants
• Dioecious


  Only male or female gametes
• Spermatophytes


  The sexual reproductive organ is the flower
• Pollination


  Transfer of the pollen from an anther to a stigma
• Vectors for pollination

  • Abiotic: wind, water
  • Biotic: insects, birds, bats
• Wind pollination


  • Stamen and stigma exposed to air, large amount of pollen, Pollen smooth, light, easy airborne, Stigma feather-like to catch pollen from wind
• Animal pollination


  • Pollen are sticky to stick to the body, Flower scented and produce nectar, Floral parts are showy
• Fertilization


  1. Male gamete fuses with female gamete to form zygote

  2. Zygote divides and forms an embryo

  3. Ovule becomes the seed

  4. Ovary becomes the fruit