1.2 Cell Structure and Organisation

1.2 Cell Structure and Organisation

1. Cell Organisation

   • Two different types of cells
     • Prokaryotic Cells
       • Found in bacteria and blue-green algae
       • No membrane-bound organelles
       • DNA lies free in the Cytoplasm
       • No nuclear membrane or ER
       • Ribosomes are smaller
       • Cell wall containing murein
     • Eukaryotic Cells
       • Found in plants, animals, fungi and protoctists
       • Membrane-bound organelles
       • DNA located on Chromosomes
       • Distinct membrane-bound nucleus
       • Ribosomes are larger
       • Cell wall in plants made of cellulose
   • Viruses
     • causes a variety of infectious diseases in humans, animals and plants
     • They are extreamely small
     • can be called a 'non-cell'
       • no cytoplasm
       • no organelles
       • no chromosomes
     • Outside a living cell a virus exists as an invert 'viron'
     • Made up of two comonents
       • Nucleic acids
       • protein coat

2. Cell Structure

   • Cytoplasm
     • highly organised
     • consisting of a soluble ground substance called cytosol
   • Nucleus
     • controls the cell's activities
     • contains chromosimes
   • nuclear envelope
     • double membrane around the nucleus
     • has pores in it to allow transport of mRNA
   • nucleoplasm
     • the cytoplasm type substance in the nucleus
     • contains chromatin
       • DNA bound to protein
   • Nucleolus
     • Manufactures RNA which is needed to make ribosomes
   • Mitochondrion
     • Sites of ATP Synthesis
   • Endoplasmic Reticulum (ER)
     • Rough
       • ribosomes on the outer surface
       • transporting proteins made by the ribosomes
     • Smooth
       • membrane with a lack of ribosomes
       • Concerned with they synthesis and transport of lipids
   • ribosomes
     • protein synthesis
   • Golgi Body
     • produces secretory enzymes
     • secreting carbohydrated
     • Producing glycoprotein
     • Transporting and storing lipids
     • Forming lysosomes
   • Lysosomes
     • contain and isolate digestive enzymes
   • Centrioles
     • during cell division they divide and go to the poles
     • synthesise the microtubules of the spindle
   • Chloroplasts
     • found in cells of photosynthrsising tissue
     • sites of photosynthesis
   • Vacuole