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Biology (living organisms (variety of living orgianisms (characteristics…

- - - - fungi (moulds, mushrooms, yeast)
      - prokaryotes (bacteria, blue-green algae)
      - plants (all green plants)
        
        flowering plants
        
        Monocotylendons examples:
        plams
        orchids
        wheat
        
        Eudicotyledons examples:
        Buttercups
        dandelions
        oak trees
      - protoctists (Amoeba, Chlorella and Plasmodium)
      - animals (all multicellular animals)
    - - phylum
      - class
      - order
      - family
      - genus
      - species
    - - Invertebrates:
        jointed legs
        a segmented body (their body has different sections)
        a hard exoskeleton (their skeleton is on the outside rather than on the inside)
        
        examples :
        insects
        arachnids
        crustaceans
        myriapods
        annelids
        Nematodes
        Molluscs
  - - - movement
      - reproduction
      - sensitivity
      - growth
      - respiration
      - nutrition
      - excretion
    - - cell structure:
        the cell consists of 3 main things;
        Cytoplasm, nucleus, cell membrane
        
        they do not have cell wall, doesnt contain chloroplasts so animals cant carry out photosynthesis, may store carbohydrates as glycogen.
    - - cell structure: they have 6 main parts;
        cell membrane, nucleus cytoplasm, chloroplast, vacuole, cell wall
        
        Plant cells contain chloroplasts so plants can carry out photosynthesis. They store carbohydrates as starch or sucrose.
    - - cell structure:
        these cells contain 6 key parts;
        cytoplasm, ribosome, mitochondrion, nucleus, cell wall, cell membrane
        
        Some fungi are pathogens, for example the fungal infection which causes athlete’s foot. Fungi cannot carry out photosynthesis. Instead they use saprotrophic nutrition. They secrete enzymes onto their food so that digestion happens outside the fungal cells. They then absorb the digested organic products.
    - - cell structure:
        the cell structure here consists of 6 elements and they are;
        cell wall, ribosome, cell membrane, large circular DNA molecule, plasmids, cytoplasm
        
        Some bacteria can carry out photosynthesis, but most bacteria feed from other organisms (living or dead)Some bacteria are pathogens.
    - - Some protoctists are pathogens. ome protoctists, such as Amoeba, have features like an animal cell. Others, such as Chlorella, have chloroplasts and are more like plants.
    - - Virus particles have a variety of shapes. They do not have a cellular structure. Instead, they have a core of genetic material surrounded by a protein coat. Their genetic material can be DNA or RNA, but not both.
  - - - In order of increasing complexity, multicellular organisms consist of:
        organelles → cells → tissues → organs → organ systems
      - Organelle: Cell structure that is specialised to carry out a particular function or job
      - Cell: Basic structural and functional unit of a living organism
      - Tissue: Group of cells with similar structures, working together to perform a shared function
      - Organ: Structure made up of a group of tissues, working together to perform specific functions
      - Organ system: Group of organs with related functions, working together to perform body functions
    - - Many cells are specialised. They have structures that are adapted for their function. For example, muscle cells bring parts of the body closer together. They contain protein fibres that can contract when energy is available, making the cells shorter.
        
        ciliated cell
        
        function:
        Pushes and moves mucus from one place to another. the cilia in the respiratory tract move mucus containing trapped microbes and dust
        
        Red blood cell
        
        function:
        Transports oxygen from the lungs to the body tissues for aerobic respiration
        
        root hair cell
        
        function:
        absorb water and minerals from the soil water
        
        xylem vessel
        
        function:
        Transport water in the plant, support the plant
    - - Magnification=measured size/actual size
      - Microscopes are used to study cells. Modern light microscopes can magnify images about 1500 times, while electron microscopes can magnify images about two million times
  - - - diffusion is one of the main processes that allows dissolved or gaseous substances to pass through the cell membrane.
      - Diffusion occurs when particles spread. They move from a region where they are in high concentration to a region where they are in low concentration. Diffusion happens when the particles are free to move. This is true in gases and for particles dissolved in solutions - but diffusion does not occur in solids.
      - particles diffuse down a concentration gradient, from a high concentration to an area of low concentration. this is the reason the smell of cooking travels.
      - diffusion in living organisms
        
        oxygen and carbon dioxide, dissolved in water, are exchanged by diffusion in the lungs.
        
        Products of digestion, dissolved in water, can pass across the wall of the small intestine by diffusion. Their concentration is higher in the small intestine than their concentration in the blood, so there is a concentration gradient from the intestine to the blood.
    - - its important when trying to understand the movement of substances across cell membranes
      - the solute is sucrose
        water is the solvent
    - - the diffusion of water molecules from a higher concentration to a lower concentration though a partially permeable membrane
      - Partially permeable membranes are also called selectively permeable membranes or semi-permeable membranes. They let some substances pass through them, but not others.
      - osmosis in cells
        
        Plant cells
        
        Plant cells have a strong cellulose cell wall on the outside of the cell membrane. This supports the cell and stops it bursting when it gains water by osmosis.
        
        water enters the cell by osmosis the cytoplasm pushes against the cell wall and the cell becomes turgid
        
        Water leaves the cell by osmosis. The cytoplasm pulls away from the cell wall (plasmolysis) and the cell becomes flaccid and the plant wilts
        
        Animal cells
        
        Animal cells do not have a cell wall. They change size and shape when put into solutions that are at a different concentration to the cell contents
        
        For example, red blood cells:
        gain water, swell and burst in a more dilute solution (this is called haemolysis)
        lose water and shrink in a more concentrated solution (they become cremated or wrinkled)
        
        Osmoregulation involving the kidneys ensures that the concentration of the blood stays about the same as the concentration of the cell contents.
- - - - Carbohydrates:
        the unit of carbohydrates are simple sugars such as glucose and fructose these are called monosaccharides
        
        Monosaccharides: Glucose and fructose have the same molecular formula C6H12O6. however, their structure is different