levels of organisation

Cards (11)

    • cells are the basic building blocks of all living organisms
    • as an organism develops, cells differentiate to form different types of cells. They become specialised
    • most types of animal cell can differentiate throughout their life
    • as a cell differentiates, it may change shape or different sub-cellular structurs develop to let it carry out a specific function
  • nerve cell
    A) axon
    B) ribosome
    C) nucleus
    D) cytoplasm
    E) cell membrane
    F) dendrites
    G) sheath
  • Muscle Cell
    A) ribosomes
    B) mitochondria
    C) nuclei
    D) cell membrane
  • Muscle cell
    • Function: contraction for movement
    • Adaptations:
    • There are three different types of muscle in animals: skeletal, smooth and cardiac (heart)
    • All muscle cells have layers of protein filaments in them. These layers can slide over each other causing muscle contraction
    • Muscle cells have a high density of mitochondria to provide sufficient energy (via respiration) for muscle contraction
    • Skeletal muscle cells fuse together during development to form multinucleated cells that contract in unison
  • Sperm Cell
    A) flagellum
    B) mitochondria
    C) cytoplasm
    D) nucleus
    E) cell membrane
    F) acrosome
  • Root hair cell
    A) ribosomes
    B) mitochondria
    C) nucleus
    D) cytoplasm
    E) vacuole
    F) root hair
    G) cell wall
    H) cell membrane
  • Root hair cell
    • Function: absorption of water and mineral ions from soil
    • Adaptations:
    • Root hair to increase surface area so the rate of water uptake by osmosis is greater (can absorb more water and ions than if SA were lower)
    • Thinner walls than other plant cells so that water can move through easily (due to shorter diffusion distance)
    • Permanent vacuole contains cell sap which is more concentrated than soil water, maintaining a water potential gradient
    • Mitochondria for active transport of mineral ions
  • Xylem
    A) continuous
    B) water
    C) lignin
  • Xylem
    • Function: transport tissue for water and dissolved ions
    • Adaptations:
    • No top and bottom walls between cells to form continuous hollow tubes through which water is drawn upwards towards the leaves by transpiration
    • Cells are essentially dead, without organelles or cytoplasm, to allow free passage of water
    • Outer walls are thickened with a substance called lignin, strengthening the tubes, which helps support the plant
  • Phloem
    A) phloem
    B) companion
    C) sugars
  • Phloem
    • Function: transport of dissolved sugars and amino acids
    • Adaptations:
    • Made of living cells (as opposed to xylem vessels which are made of dead cells) which are supported by companion cells
    • Cells are joined end-to-end and contain holes in the end cell walls (sieve plates) forming tubes which allow sugars and amino acids to flow easily through (by translocation)
    • Cells also have very few subcellular structures to aid the flow of materials