Analogy of Animal Cell

Animal Cell

Animal cells are in our human bodies as well in animals. There are various kinds of animal cells such as red blood cell, nerve cell and so on. Different cells have different appearances and the figure on the left shows the general form of animal cells

An animal cell normally consists of many organelles, including:

a) Nucleus

b) Cytoplasm

c) Cell membrane(aka Plasna membrane)

d) Endoplasmic reticulum

h) Lysosomes

g) Mitochondria

h) Golgi apparatus

i) Ribosomes

Here I would like to make analogy for some of the parts.

Nucleus

Nucleus is the central part as well as the most important part of a cell. It contains nuleolus, chromatin, nucleoplasm and is surrounded by a porous nuclear envelope. Nucleus controls all the important activities of the cell so we can say that it is just like the headquarter of the whole cell.

-Nucleolus

Nucleolus is in the middle of the nucleus. It is a knot of chromatin and it is the part that manufactures ribosomes(small particles that produces proteins). It is the radical resource of the proteins in the cell.

Ribosomes

Ribosomes are small round structures made by nucleolus. They play a very essential role in the process of synthesising proteins. They can be sorted into two types-ribosomes attached to rough ER and free ribosomes. The ribosomes of the first type are found along rough ER and they produce the basic proteins in it. Free ribosomes are found lying in the cyoplasm. Proteins made by these ribosomes are normally used within the cytoplasm ot the cell. We can say that ribosomes are like manufactorers.

Rough Endoplasmic Reticulum(Rough ER)

Rough endoplasmic reticulum has a rough surface when viewed under the electron microscope. This is because small particles(ribosomes) are attached to its outer surface. Rough ER is involved in the synthesis and transportation as well as sorting of proteins.When proteins are made in rough ER, it will form vesicles to transport the proteins to golgi apparatus. If we compare the nucleus to the headquarter of the cell, the is just like the Ministry of Transportation.

Golgi Apparatus

Golgi Apparatus, also known as Golgi body, is shaped like a disc. It is made up of stacks of flattened spaces surrounded by membranes. Vesicles(small spherical spaces enclosed by a membrane) can be seen fusing with one side of the Golgi apparatus andpinching off from the opposite side all the time. In this way, Golgi apparatus is involved in transport of molecules out of the cell since the molecules are packaged in the vesicles. Another function of is modifing suvstances made by the rough ER. In the animal cell, the Golgi apparatus is like the postal office.

Lysosomes

Lysosomes are spherical organelles that contain digestive enzymes. They are built in the Golgi apparatus. They have the ability to fuse with vacuoles and release enzymes into it. Lysosomes are usually more than one in a cell. They are responsible for digestion of excess or worn organelles, food particles and engulved viruses and bacteria. Therefore they are call "scrap yard" of a cell.

Mitochondria

Mitochondria (plural form of mitochondrion) are small sausage-shaped organelles lying in the cytoplasm. Aerobic respiration, during which food substances are oxidised, occurs in them. Energy released during respiration may be stored as Adenosine Triphosphates(ATP). That's why mitochondria can provide the cell with energy. This energy may be used by the cell to carry out cell activities, for instance, growth and reproduction. Mitochondria are just like the Ministry of Energy in the cell.

Plasma Membrane

Plasma membrane, aka cell surface membrane, is a thin layer that surrounds the cytoplasm of the cell. Unlike cell wall that plant cells have, plasma membrane is not strong enough to support the cell in order to help it have a fixed shape. The plasma membrane is a partially permeable membrane (not neccessarily semi-permeable) so it allows only some substances to cross it. Therefore, the plasma membrane controls substances entering or leaving the cell.