B1 - Variety of Living Organisms

• What do all organisms do? (MRS H GREN)

  Movement, respiration, sensitivity, homeostasis, growth, reproduction, excretion, nutrition
• Eukaryotic organisms


  Made up of cells that have a nucleus and a distinct membrane
• Tissue


  A group of cells working together to perform a shared function, often with a similar structure
• Cell


  The basic building block of all living things
• Organelle


  A specialised unit within a cell which performs a specific function
• Example of a pathogen for a virus


  Tobacco mosaic virus
• Example of a pathogen for a protoctists


  Malaria
• Example of a pathogen for a bacteria


  Salmonella
• Example of a pathogen for a fungi


  Athletes foot
• Pathogens


  Microorganisms that can give an infectious diseases
• Prokaryotic organisms


  Made up of cells without a nucleus, as the nuclear information is found in the cytoplasm
• Organ


  A structure made up of groups of different tissues working together to perform specific functions
• Organ system


  A group of organs with related functions working together to perform certain functions within the body
• Nucleus


  Contains all genetic material and controls activities of the cell (found in animal cells, plant cells, fungi cells)
• Cytoplasm


  Site of chemical reactions (found in animal cells, plant cells, fungi cells, bacteria cells)
• Cell membrane


  Controls the movement of substances into and out of the cell (found in animal cells, plant cells, fungi cells, bacteria cells)
• Mitochondria


  Site of respiration (found in animal cells, plant cells, fungi cells)
• Ribosomes


  Site of protein synthesis (found in animal cells, plant cells, fungi cells, bacteria cells)
• Glycogen


  Storage of carbohydrates
• Starch


  Storage of carbohydrates
• Vacuole


  Stops plant from falling over, contains cell sap (found in plant cells, fungi cells)
• Cell wall


  Protective layer and helps maintain shape (found in plant cells, fungi cells, bacteria cells)
• Chloroplast


  Site of photosynthesis (found in plant cells)
• Flagella


  Allows the cell to swim (found in bacteria cells, some animal cells)
• Slime capsule


  Protects the cell (found in bacteria cells)
• Plasmid


  Circular loop of genetic material (found in bacteria cells)
• Chromosome


  Contains genetic information (found in bacteria cells)
• Animals


  Multicellular; heterotrophic (feed on other organisms to get nutrition); can move; have a nervous coordination; store carbohydrates as glycogen

  
• Plants


  Multicellular; autotrophic (make their own food); store carbohydrates as starch or sucrose; have cellulose cell walls

  
• Fungi


  Multicellular (except for yeast); have chitin cell walls, made of network of fibres called a mycelium of hyphae which have many nuclei; store carbohydrates as glycogen; feed by saprotrophic nutrition
• Ciliated cell


  Function - movement of mucus in trachea and bronchi

  Adaptation - cilia beat to move mucus and trapped particles

  
• Nerve cell


  Function - conduction of impulses

  Adaptations - long so that nerves can run to and from different parts of the body to the central nervous system; has extensions and branches to communicate with other nerve cells/muscles/glands; the axon is covered in a fatty sheath, which insulates the cell and speeds up the nerve impulse

  
• Red blood cell


  Function - transport of oxygen

  Adaptations - biconcave shape to increase surface area; contains haemoglobin which joins with oxygen to transport it; no nucleus to increase surface area

  
• Sperm cell


  Function - reproduction

  Adaptations - haploid nucleus (contains have the number of chromosomes) has genetic material for fertilisation; acrosome contains digestive enzymes to penetrate the egg; lots of mitochondria to increase rate of respiration (ATP needed for swimming);flagellum allows the cell to swim

  
• Egg cell


  Function - reproduction

  Adaptations - a lot of cytoplasm, which contains nutrients for growth and development; haploid nucleus; cell membrane becomes hard after fertilisation to stop other sperm cells from entering

  
• Root hair cell


  Function - absorption of water and mineral ions from the soil

  Adaptations - root hair increases surface area, which maximises the absorption; thin cell walls, which makes it easier for the substances to pass through; no chloroplasts as they are found underground; lots of mitochondria to provide energy for active transport

  
• Palisade mesophyll cell


  Function - photosynthesis

  Adaptations - column shaped to maximise absorption of sunlight; tall structure and large surface area to maximise absorption; many chloroplasts; full of starch grains to store food

  
• Xylem vessel


  Functions - conduction of water through the plant; support for the plant

  Adaptations - no top and bottom walls; cells are dead with no organelles to allow free passage of water; walls are thickened with lignin for support

  
• Stem cells


  Unspecialised cells that are able to renew themselves for long periods of time by cell division.
• Advantages of stem cells

  Can be used to treat a wide range of diseases (eg paralysis or diabetes); reduce the risk of organ rejection when organs develop from stem cells; can test potential drugs using animal simulation