Selasa, 09 Oktober 2012



According to the numbers of cells, organism body divided into two, they are:
a.      Unicellular; is living organisms which have only one cell, such as bacteria, Amoeba, Paramecium and Euglena.
b.      Multicellular; is living organisms consisting of more than one cell. Such as plants and animals.
Simply, life organization levels of multicellular organism are:
Cell à Tissues à Organs à Organ System à Organism
The word cell comes from Latin “cellula”, meaning, a small room. Cells are the smallest functional unit which forms the body of living organisms. The term cell was developed by Robert Hooke in 1665. The size of a cell is very small so that it can only be visible if it is observed using a microscope.
Commonly, cell structure consists of cell membrane and protoplasm. Protoplasm is the living contents of a cell. Protoplasm located outside the nucleus is called cytoplasm. Cell organells are located in the cytoplasm. Organelle is unit inside the cell which has special function.
The Part of Cell and Cell Organelles :
1.      Cell Membrane (Plasma Membrane)
The plasma membrane is the outer part of a cell. It controls the traffic of any material in and out of the cell. The plasma membrane enables oxygen and food to move into the cell, and residual substances to be disposed out of the cell. Cell membrane has characteristic semipermeable. It means, cell membrane only can be passed by certain substances, but can not be passed by other substances. Substances which can pass it such as water, substances which soluble in fat, and certain ion.
In plant cell, cell membrane is protected by a strong and thick cell wall. The cell wall is composed of cellulose which gives the characteristic of a constant and stiff shape to a plant cell. The plasma membrane in animal cell is not protected by a cell wall; therefore its shape is constantly changing.
2.      Cytoplasm
Cytoplasm is the liquid which fill the cell. It consists of various substances, such as water, protein, carbohydrate, fat, enzymes, hormone, and minerals. Cytoplasm has functions as the place where the metabolism cell reaction occurs.
3.      Nucleus
Generally, the nucleus is round in shape and located in the middle of the cell. Inside the nucleus, there are chromosomes containing genes, which basic function is to carry hereditary materials across generations.
4.      Endoplasmic Reticulum (ER)
ER function is to transfer substances inside the cell. ER membrane is the continuance of nucleus outer membrane that form winding cannal through the cytoplasm and end in cell membrane. There are 2 types of ER, that are rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). On RER membrane, the ribosomes adhere, but nothing on SER membrane. Besides transfer substances inside the cell, SER also functions in making fat.
5.      Ribosome; is small round in shape. There are ribosomes that adhere on ER membrane, and there are free in cytoplasm. Ribosome functions to synthesize protein from amino acids (synthesize protein).
6.      Golgi complex; it fom like laminar pockets. It functions as secretion unit of protein and mucous. That’s why Golgi complex is called secretion organelle. In plant cell, Golgi complex is called dictiosome. 
7.      Mitochondria; is oval like peanut seed. It has outer and inner membrane. Mitochondria functions as energy producer to life process. Inside, the respiration process occurs for produce energy.
8.      Plastid; is organelle with compound membran which have certain pigmen. Plastid with green pigmen (chlorophyll) is called chloroplast, and plastid that contains of amyllum is called amyllopast. Chlorophyll is pigment which is used in the photosynthesis process. Chloroplast is available in plant cell only.
9.      Lysosome; is a pocket inside cytoplasm which contain of digestive enzymes. Lysosome functions to digest the part of damage cell or strange things that enter the cell.
10.  Centriole; consists of some cylinders that compose perpendicular. It functions in animal cell division.
11.  Vacuole; is clearly visible in a plant cell. In an old plant cell, the vacuole is big in size and contains of food storage and pigments. In animal cell, a vacuole is seldom found.
Image 1.
 Animal cell                                                  Image 2. Plant cell
The differences between animal cells and plant cells
Structure of animal and plant cell is different. In plant cell, there is cell wall which covers the cell membrane. Cell wall composed by cellulose and pectin so that plant cell has constant shape characteristic. In plant cell, there is chloroplast. Animal cell has centriole when the cell cleaves, but plant cell doesn’t has. Centriole functions to collect chromosomes. Besides, plant cell has big vacuole, but in animal cell, it seldom found. If it present, the size is small and not clearly visible.
The differences of animal and plant cell can be seen in table below:
Cell organelles
Plant cell
Animal cell
Cell Wall
not present
not present
not present
present and big
(clearly visible)
seldom found and if present, usually very small

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