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Friday, 7 November 2014

Definitions

Cell
A smallest unit of structure and function of living organisms
Tissue
A group of cells working together to perform a specific function
Organ
A group of tissues working to perform one or more functions

Magnification

Magnification

Magnification = Size of an image
                           Actual size

For exampe the question is
*400

1) Make a large diagram of a cell
Ans ) Draw a large diagram of any cell


2) Find Magnification of you drawing
  • First find the length of RBC in cell
  • Suppose x=3 cm
  • Find the actual size of RBC
Magnification= Image size
                          Actual size
400 =        3        
          Actual size
Actual size =   3  
                      400
Actual size = 0.0075
  • find the length of drawn image
  • suppose it is 10 cm
Magnification =    10    
                           0.0075
Magnification = x1333.33

Note:
  • If the magnification is not given ( x400 ) then leave the first step to find the actual size
  • x is necessary to use in the answer of magnification

Cell organelles

Organelles in cell

     Cell wall
  • Made of cellulose
  • found in plants
  • prevent cell from bursting
    Cell membrane
  • Found in both plants and animals
  • controls the movement of substances into and out of the cells
    Chloroplast
  • A double membrane bond of cell organal
  • found in plants
  • contains a green pigment, chlorophyll
  • traps sunlight
  • converts it into chemical energy
  • for the synthesis of carbohydrates
   Nucleus
  • Found in both plants and animals
  • Controls the reproductive activity of cell
  • repairs the worn off cells

Tuesday, 4 November 2014

Differences b/w animal and plant cell

    Difference b/w animal and plant cell
 
    Plant cell
  • Large size
  • Regular shape
  • Cell wall present
  • Centrioles absent
  • Chloroplast present
  • Permanent, large vacuole
  • Both mitosis and meiosis occur
   Animal cell
  • Small size
  • Irregular shape
  • Cell wall absent
  • Centrioles present
  • Chloroplast absent
  • Temporary, small vacuole
  • Meiosis occur
Cell structure and component

     How to prepare a microscope
  • Take a glass slide
  • Place the specimen on the slide
  • Pour a few drops of dye on the slide
  • Place the cover slide on it
  • Soak the excess stain
  • Place the slide on the stage
  • Rotate the nose piece to adjust the power of the objectives
  • Looking through the slide of the stage with the course adjustment knob
  • Looking though the eye piece, lower down the stage with fine focusing lens
    Reading your observation
  • Taking a photomicrograph
  • Making a diagram