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cell structure (cells and organelles (functions of organelles (plasma…

- - - - some extras: a cell wall, a vacuole, chloroplasts
  - - - description= found on the surface of a cells and just inside the cell wall on p cells. is made of lipids and protein
      - function= regulates the movement of substances in and out of cell. has receptor molecules which allow it to respond to chemicals e.g. hormones
    - - description= a rigid structure that surrounds plant cells. made of cellulose
      - function= supports plant cells
    - - description= a large organelle surrounded by nuclear envelope (a double membrane) which contains many pores. contains chromatin and nucleolus
      - function= chromatin is made from proteins and dna (dna controls cells activities). the pores allow substances to move between the nucleus and cytoplasm. the nucleolus makes ribosomes
    - - description= a round organelle surrounded by membrane with no clear internal structure
      - function= contains digestive enzymes and are used to digest invading cells or to break down worn out components of cell
    - - description= a very small organelle that either floats in cytoplasm or is attached to RER
      - function= where proteins are made
    - - description= a system of membranes enclosing a fluid filled space (cisternae). surface is covered in ribosomes
      - functions= folds and processes proteins that have been made at the ribosomes. cisternae can act as transport system from certain systems within cell
    - - description= similar to RER but with no ribosomes
      - functions= synthesizes and processes lipids
    - - description= a small fluid filled sac in cytoplasm surrounded by membrane
      - functions= transports substances in and out of cell (via cell membrane) and between organelles. formed by the Golgi apparatus, ER, cell surface
    - - description= a group of fluid filled flattened sacs. vesicles are often found at the edge of the sacs
      - functions=it processes and packages new lipids and proteins. it also makes lysomes
    - - description= has a double membrane - the inner is folded to form cristae. inside is the matrix which contains enzymes involved in respiration
      - functions= the site of aerobic respiration where ATP is produced
    - - description= surrounded by double membrane and contains thylakoid membranes. these are stacked in some parts to form grana. grana are linked by lamellae
      - functions= the site of photosynthesis. happens in grana and stroma
    - - description= small hollow cylinders containing a ring of microtubules. motor proteins walk along tubulin threads to chromosomes during mitosis and meiosis
      - functions= involved in the separation of chromosomes during cell division and forming cilia and udiulipodia
    - - description= small hair-like structures found on the cell membrane of some animal cells. in cross section they have an outer membrane and a ring of 9 pairs of protein microtubules inside with a single pair of microtubules in the middle
      - functions= the microtubules allow cilia to move. this movement is used by the cell to move substances along the cell surface
    - - description= surrounded by a plasma cell membrane and have 9 pairs of microtubules on edge and two microtubules in centre
      - function= microtubules contract to make flagella move thus moving the cell
    - - description= contains red microfilaments, intermediate filament, micrtubules
      - functions= helps cell maintain shape and helps cell move
    - - description= contains fluid surrounded by tonoplast membrane
      - function= maintains cell stability and keeps it turgid
- - - - the organelles in cells are surrounded by cytoplasm
      - contains protein threads are called the cytoskeleton
      - in eukaryotes the protein threads are arranged as microfilaments and microtubules
    - - the microtubules and microfilaments support the cells organelles (keeping them in position)
      - they help strengthen the cell and maintain the shape
      - transport organelles and substances within the cell e.g. vesicles, chromosomes during cell division
      - the proteins of the cytoskeleton can also cause the cell to move e.g. cilia and flagella
- - - - TEM's use electromagnets to focus a beam of electrons which is transmitted through specimen
      - denser parts of specimen absorb more electrons which makes them look darker on final image
      - pros
        
        create high resolution images
        
        can see internal structures in detail
        
        max magnification= x1 000 000
        
        max resolution= 0.0001ym
      - cons
        
        have to be thinly sliced
        
        angle which they are cut can affect final image
        
        2D
    - - SEM's scan a beam of electrons across specimen knocking off electrons from specimen which are gathered at cathode ray tube to form image
      - pros
        
        images can be 3D
        
        magnification= x1 000 000 (less than)
        
        resolution= 0.005ym
      - cons
        
        have a lower resolution than TEM's
    - - common stains for TEM's= heavy metals (lead)
      - Differential Staining is a staining process which uses more than one chemical stain. Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism.
      - process
        
        1) dehydrate the cells
        
        2) embed in wax so they don't distort
        
        3) slice with a special instrument into thin slices
        
        4) mount on a slide
      - used for a light microscope and TEM's
      - stains
        
        eosin= cytoplasm
        
        sudan red= lipids
        
        acetic ordin= binds to dna
        
        iodine= starch
    - - magnification= x1500
      - resolution= 0.2ym
      - graticule eye piece= sits behind just behind lens and measures in ocular divisions
      - stage micrometer= put on stage like a slide and is used to measure the size of each ocular division
      - calibartion
        
        1) measure amount of ocular divisions in 1mm
        
        2) stage micrometer measures in mm
        
        3) this only works for each objective lens
        
        4) change the magnification
    - - works by passing a laser beam through a light source aperture which is then focused by an objective lens into a small area on the surface of your sample and an image is built up pixel-by-pixel by collecting the emitted photons from the fluorophores in the sample.
      - creates high resolution and high magnification images