What is DIFFUSION? :o

Diffusion happens due to a molecule's thermal motion. The thermal motion of a individual molecules are RANDOM. However, the total population of molecules tend to move from a higher concentration to a lower concentration. All in all, DIFFUSION causes molecules to move from a higher concentration to lower concentration.

>>> http://chemistryelementsadia.blogspot.sg/2012/07/diffusion-o.html

Functions of some parts of a CELL :3

Nucleus : It is the centre of all the activities happening in the cell.It controls all the activities. Therefore, it is the "brain" of the cell. 
Nuclear Membrane : It is a double-layered membrane enclosing the nucleus of a cell that controls what enters and leaves the nucleus chromatin: combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are: to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and prevent DNA damage, and to control gene expression and DNA replication.(from Wikipedia)
Cytoplasm: The cytoplasm is a semi fluid material surrounding organelles; site of many cellular reactions. It also acts as a medium for transport inside the cell. (from WikiAnswers) 
Cell Membrane :  It protects the cell from harmful contents of the outside world, thus keeping the interior of the cell safe. 
Mitochondria : The main function of the mitochondrion is the production of energy, in the form of adenosine triphosphate (ATP). The cell uses this energy to perform the specific work necessary for cell survival and function. (from Epilepsy.com) 
Chloroplast : It contains chlorophyll which helps a plant cell to make food for itself. 
Cellulose Cell Wall : It keeps a plant cell firm, strong and in shape.

DIAGRAM of a PLANT cell and ANIMAL cell :>

DIAGRAM of a PLANT cell and ANIMAL cell ^_<

Both animal (A) and plant (B) cells have a cell membrane (1), nucleus (2), and cytoplasm (3). But in plants there is also a cell wall (4) and certain organelles, notably chloroplasts, which are unique to plant cells

                                 Reference : http://www.daviddarling.info/encyclopedia/P/plant_cell.html

DIFFERENCES between ANIMAL cells and PLANT cells ^^

                                DIFFERENCES between ANIMAL cells and PLANT cells :D

              ANIMAL cells                                                                                    PLANT cells
- Does not have a cell wall or chloroplasts                                       -Has both a cell wall and chloroplasts.
- Has a few vacuoles (small ones)                                                    -Has a large, central vacuole

More Detailed :

Referance : http://jpsy2011.blogspot.com/2011/02/similarities-and-differences-between.html

SIMILARITIES between a PLANT cell and an ANIMAL cell :)

SIMILARITIES between a PLANT cell and an ANIMAL cell :D

• Both have Nucleus
• Both have Cell membrane
• Both have Cytoplasm
• Both have Vacuole(s)

More Detailed : 

DIFFERENCE between Prokaryote and Eukaryote Cells

                                              Difference between Prokaryote and Eukaryote cells

                                       Prokaryote Cells                                                   Eukaryote cells

                                  1) Does not have a nucleus                            1)Has a nucleus, nuclear membrane

                                  2) Single Chromosome                                  2) Multiple chromosomes

                                  3) Mitochondria Absent                                 3) Mitochondria present 

           

               Reference : Cornell University Website