Bio classification and cells

• Classification is where biologist group organism depending on their characteristics
• Main groups of organisms

  • Plants
  • Animals
  • Fungi
  • Bacteria
  • Protoctists
  • Viruses
• Eukaryotic cells


  Complex cells with a nucleus and cell organelles
• Prokaryotic cells


  Simple cells with no true nucleus, a single circular piece of DNA, and no cell organelles
• Kingdoms of Classification


  • Plants (Eukaryotic)
  • Animals (Eukaryotic)
  • Fungi (Eukaryotic)
  • Protoctists (Eukaryotic)
  • Monera (Bacteria) (Prokaryotic)
• Viruses are not in a kingdom because they do not perform the 7 characteristics of life and need to infect a host cell to reproduce
• Bacteria


  • Single-celled, contain cell wall, cell membrane, cytoplasm and plasmids, no nucleus but a circular chromosome of DNA

  
• Fungi


  • Thread-like network of hyphae make mycelium, multicellular, cell walls made of chitin, release digestive enzymes outside the cell and absorb the products, may store carbohydrate as glycogen
• Viruses


  • Very small, parasitic, outer protein coat, inner capsid and either DNA or RNA as genetic material
• Animals


  • Multicellular, usually have nervous coordination and can move from place to place, often store carbohydrate as glycogen
• Plants


  • Multicellular, have chloroplasts with chlorophyll for photosynthesis, cell walls made of cellulose, store carbohydrates as starch, transport carbohydrates as sucrose
• Protoctists


  • Single-celled organisms, some more like animal cells, some more like plant cells, often pathogens
• Pathogen


  Microbes/microorganisms that cause disease, can be bacteria, fungi, protoctists or viruses
• Pathogens


  • HIV (virus), Ringworm (fungi), Pneumococcus (bacteria), Plasmodium (protoctist)
• Prokaryote cell structure

  Cell membrane, ribosomes, cytoplasm, circular chromosome of DNA called a nucleoid, some have flagella and plasmids
• Cell structures in eukaryotes

  • Nucleus
  • Cytoplasm
  • Cell membrane
  • Cell wall
  • Chloroplast
  • Vacuole
• Functions of cell structures

  Nucleus - contains genetic information and controls cell activities

  Cytoplasm - watery fluid allowing organelles to move and chemical reactions

  Cell membrane - barrier controlling what enters and leaves the cell

  Mitochondria - carry out aerobic respiration to make ATP

  Ribosomes - where proteins are made

  Cell wall - made of cellulose to support plant cells

  Chloroplast - contains chlorophyll for photosynthesis

  Vacuole - space containing cell sap
• Animal cells have no cell wall, large vacuole or chloroplasts, unlike plant cells
• Unicellular organisms

  Have a high surface area to volume ratio, allowing diffusion of substances in and out of the cell
• Multicellular organisms

  Need a transport system like blood and a pump like the heart to deliver substances to all their cells
• Cell differentiation is important for the development of specialised cells
• Specialised cells in animals

  • Brain
  • Eyes
  • Blood
  • Heart
  • Liver
  • Bone marrow
  • Skin
  • Muscle
• Adult stem cells

  Found in limited numbers in certain body locations, can differentiate into related cell types only
• Locations of adult stem cells

  • Brain
  • Eyes
  • Blood
  • Bone marrow
• Stem cells have potential for treating patients, growing organs, and medical research, but there are clinical, ethical and social issues with their use
• Organ systems in humans


  • Reproductive
  • Circulatory
  • Nervous
  • Musculo-Skeletal
  • Endocrine
  • Digestive
  • Excretory
• Organ systems in plants

  • Reproductive
  • Transport
  • Nutritional
  • Support and Anchorage
• Examples of specialised cells in animals are red and white blood cells, sperm cells, egg cells.
• Stem cells are undifferentiated which means they are not specialised for any specific function.