Bio 2A

  • Created by: Shine.7
  • Created on: 15-02-15 12:43
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  • Bio 2A
      • spreading out of particles from an area of HIGH conc to area of LOW conc
      • LIQ/GAS-particles free to move
        • bigger difference in concentration,faster diffusion
      • Rate of diffusion affected by:          distance, surface area, concentration,temp
      • CELL MEMBRANES: let stuff in n out. Dissolved substances can move by diffusion. ONLY very small molecules move through( Oxygen,Glucose,Amino,Water)
        • Big molecules like starch+proteins dont!!
        • particles move randomly so they go both ways: but if there's alot more on one side of the membrane= NET MOVEMENT (overall) from that side
      • TRANSECTS:study distribution along a line either count or use quadrat
      • QUADRATS: place it at a random point and count organisms. Repeat and workout the mean. Repeat again and compare the two means.
        • Mean: total/number of quadrats
        • Population size: mean x total area
      • RELIABILITY: large sample size-more representative
        • VALIDITY: control all variables and use random samples
      • Factors which affect organisms: availability of water,light,temp,nutrients,oxygen
    • CELLS
      • Yeast cell: single cell w/ n/cw/cm/cytoplasm
        • Bacteria: ^ same but no NUCLEUS-floats
      • 8 organelles:      Nucleus    Cytoplasm              Cell Membrane      Mitochondria  Ribosomes    Cell wall         Vacuole        Chloroplasts
      • Specialised cells:              palisade leaf cells/guard cells/red blood cells/sperm cell/root hair cell
        • Muscular tissue: contracts to move
          • Epithelial tissue: covers parts of body
      • Multicellular:consisting of many cells
      • DIFFERENTIATION: cell becomes specialised for particular job
      • similar cells: tissues          different tissues:organ  different organs:organ system
      • CO2+H20=sunlight=C6H12O6+O2
      • Use for glucose: RCPSS
      • PLANT TISSUES: Mesophyll tissue (photosynthesis occurs)      Xylem+Phloem(transportation)                Epidermal tissue (covers the plant)
        • Chloroplast-chlorophyll-absorb sunlight-converts Co2-photosynthesis
      • LIMITING FACTORS: light,Co2,temp,water
      • Graphs:          rate of psynthesis increases steadily//up to a certain point//graph flattens out=no longer limiting factor//other factors must be increased.
        • Temp graph:     too low: enzymes work slowly    too high:denatured (45)
        • Fair test(keep variable constant): Bench Lamp-control intensity of light.              Water bath-keep temp constant
  • Measure how common an organism is in 2 areas
  • study changes across an area
  • Greenhouses: Temp in winter:heater   Temp in summer: too hot-ventilation+shades                 Artificial light                  Co2- paraffin heater realeses Co2.
    • ADV: plants free from pests+disease                     grow crops all year
  • DIS: cost a lot+ waste if more is given to the plant than needed
  • Glandular tissue: makes+secretes hormones+enzymes


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