Section 1: The nature and variety of living organisms

• 1.1: Understand that living Organisms share the following Characteristics

  Movement - All living organisms move.

  Respiration - All living organisms respire.

  Sensitivity - All living organisms respond to their environment.

  Growth - All living organisms grow and develop.

  Reproduction - All living organisms reproduce.

  Excretion - All living organisms excrete waste.

  Nutrition - All living organisms require nutrition.

  Control - All living organisms control internal conditions.
• Plants are multicellular organisms that store carbohydrates as starch.
• The structure of a plant includes a nucleus, which is a membrane-bound organelle containing chromosomes.
• Chloroplasts are proteins that carry out photosynthesis.
• Mitochondria are proteins that carry out cell respiration.
• Cytoplasm fills the cell to facilitate chemical reactions and holds organelles in place.
• Vacuoles are storage organelles for water and dissolved substances.
• The cell membrane is a phospholipid bilayer that controls the movement of substances into and out of the cell.
• The cell wall is made of Cellulose to protect and maintain the shape of the cell.
• An example of a plant is a herbaceous legume.
• ANIMALS CHARACTERISTICS

  • Multicellular organism
  • Stores carbohydrates as Glycogen
  • Has nervous coordination to move from one place to another
  • Structure:
  • Nucleus - membrane-bound organelle containing chromosomes
  • Mitochondria - protein to carry out cell respiration 
  • Cytoplasm - fills the cell to facilitate chemical reactions and holds organelles in place
  • Cell membrane - phospholipid bilayer that controls movement of substances into and out of cells
  • Example: Mammals, Insects
• Fungi are both multicellular and unicellular.
• Fungi store carbohydrates as Glycogen.
• Fungi are organised into a Mycelium, a thread-like structure called Hyphae that contains many Nuclei.
• Fungi feed by extracellular secretion, the release of digestive enzymes onto food to absorb organic products, a process known as saprotrophic nutrition.
• The Nucleus is a membrane-bound organelle containing chromosomes.
• Mitochondria are proteins that carry out cell respiration.
• Cytoplasm fills the cell to facilitate chemical reactions and holds organelles in place.
• The Cell membrane is a phospholipid bilayer that controls movement of substances into and out of the cell.
• Mucor or Yeast is an example of a Fungus.
• PROTISTS


  • Microscopic unicellular organism
  • Structure of protists are varied
  • Example: Amoeba (animals)
  • Chlorella (plants)
• Bacteria are microscopic organisms that cause diseases.
• Bacteria are unicellular organisms that feed on living or dead organisms.
• The structure of bacteria includes a nucleoid, a single circular strand of DNA.
• Bacteria also have a plasmid, an independent small circle of DNA.
• The plasma membrane of bacteria is a phospholipid bilayer that controls the movement of substances into and out of the cell.
• The cell wall of bacteria is made of Peptidoglycan to protect and maintain the shape of the cell.
• Bacteria have pili, protein filaments that facilitate cell adhesion and conjugation.
• 70S Ribosomes are the site of protein synthesis in bacteria.
• The flagellum of bacteria is an elongated, inflexible structure that rotates to move the cell.
• Lactobacillus Bulgaricus is a rod-shaped bacterium used in the production of Yoghurt.
• Pneumococcus is a spherical bacterium that causes Pneumonia.
• VIRUS CHARACTERISTICS

  • Non-living organism
  • Parasitic as they can only reproduce inside living host cells
  • Structure:
  • Capsid - contains genetic material (DNA or RNA)
  • Viral Envelope - made from fatty lipid molecules taken from host cells to avoid host immune system
  • Surface Protein - proteins that help recognise and bind to host cells for infection
  • Example:
  • Tobacco Mosaic Virus (plant virus that causes discolouration of the leaves of tobacco plants)
  • HIV (human virus that causes AIDS)