BIOLOGY FORM 4 CHAPTER 2 ( 1 )

Biology

Chapter 2: cell structure cell organisation.

2.4 Cell structure and function

             

                                      

         Plant Cell

     

                                        Animal cell   

1.        Nucleus

·       Large , dense , spherical organelle

·       Contain chromosomes

·       Chromosomes carry genetic information (determines the characteristic and function of cell)

·       Function: control all the activities in the cell

       

2.       Cytoplasm (not organelle)

·       Region between nucleus and plasma membrane.

·       Contains : 1) organelles

                  2)organic & inorganic

                       = provides the substance to organelles

·       Function : as the medium for biochemical reactions

3.       Plasma membrane

·       Made of protein and phospholipids

·       Separates the content of cell from the outer environment.

·       P. Membrane is semi –permeable/partially- permeable/selectively permeable

·       Function : regulates the movement of substances into and out of cell

                         

4.       Cell wall (not organelle)

·       Rigid outer layer

·       Composed at cellulose

·       Permeable to all fluids

·       Functions:  1) maintain the shape of plant cell

                    2) provides mechanical support to the cell

                       =prevent cell from rupturing(burst)

5.       Mitochondria (organelle)

·       Small spherical or cylindrical

·       Site of cellular respiration

~mitochondria produce/generate  energy

·       Store energy in form of ATP (adenosine triphosphates)

        

6.       Centrioles (only in animal cell)

·       A pair of small cylindrical structures

·       Found near nucleus

·       Function:   1)  form  spindle fibres during cell divisions

·       Present only in ANIMAL CELL.