specialisation and organisation

• organisation:

  1. cells
  2. tissues
  3. organs
  4. organ systems
  5. organisms
• types of tissue:

  • epithelial
  • connective
  • muscle
  • nervous
• stratified tissue = layers of tissue
• pseudostratified tissue = layers of differently shaped tissue
• squamous epithelial = squashed e.g. skin cells, alveoli
• cuboidal epithelial = cuboid e.g. kidney, pancreas
• colmnar epithelial = elongated e.g. villi, cillia
• stem cells:

  • non specialised cells
  • able to express their genes and divide by mitosis
  • have the potential to become many types of cells
  • embryonic stem cells and adult stem cells
• totipotent = can form any cell type in the body
• pluripotent = cannot form a viable tissue by itself
• multipotent = can form most types of cells
• oligopotent = forms cells of closely related tissue types
• unipotent = only forms cells of a particular type
• ciliated epithelium:

  • moves substances in one direction
  • contain cillia and lots of mitochondria
  • e.g. moving mucus from lungs to throat
• guard cells

  • help to regulate the rate of transpiration by opening and closing the stomata
  • high density of mitochondria and chloroplasts
• erythrocyte (red blood cell)

  • contains haemoglobin that carries oxygen
  • flat disc shape for larger surface area
  • no nucleus for more oxygen storgage
• root hair cell

  • allow plants to absorb water and other mineral ions
  • large surface area to volume ratio
• neutrophil (white blood cell)

  • part of immune system
  • flexible to mold to the shape of the pathogen
• sperm cell

  • male gamete
  • flagella used for swimming
  • acrosome in the head contains enzymes to penetrate the egg
  • contain lots of mitochondria
• palisade cell

  • primary site of photosynthesis
  • largest number of chloroplasts per cell
  • column shaped and tightly packed together so lots of light can be absorbed
• viruses

  • single molecule of nucleic acid surrounded by a protein coat (capsid)
  • nonliving - don't carry out all cell processes
  • reprograms the host cells machinery to produce more copies of itself
  • bacteriophage = a virus that infects a bacteria and reproduces inside of it
• goblet cells = produce mucus