Cell Membrane and Cytoplasm - Essay Example

Cell City Introduction Cells are the functional and structural units of life which provide the basis of biology and other related sciences. Cells can be structurally divided into two groups i.e. the prokaryotes and the eukaryotes. The basic difference between these two groups is that eukaryotes contain a nuclear membrane which surrounds the nucleus and the materials embedded in it whereas in prokaryotic cells the genetic material inside the nucleus is not surrounded by a membrane. The cells present in animals and plants are eukaryotic whereas the cells in bacteria, cyanobacteria and mycoplasmas are prokaryotic. Organelles are part of cells which work together to complete the functions of the cells. As plant and animal cells are eukaryotic this essay would revolve around the eukaryotic cells only. In this essay these different organelles of the cell would be compared to structures in the city and would provide an overview about them (1; 2; 4; 6) Cell City The eukaryotic cells in other words have membrane bounded organelles. Its constituents are the plasma membrane, Endoplasmic Reticulum, Ribosomes, Mitochondria, Golgi Apparatus, Lysosymes, Nucleus, Flagella, Cilia, Cell wall, Chloroplast and vacuoles. The animal cells and plant cells have a difference of cell wall, vacuoles and chloroplasts. The cell functions like a city to complete its functions. All the organelles work together just like in a city with collaboration so that the city is clean and everything goes on smoothly. These are the organelles of the cell which function together to produce qualitative results (1; 2). Cell Membrane The cell membrane is a very important structure which forms the outer covering of the cells. Its integrity and normal working is very essential for the proper functioning of the human body as well as the carrying out of normal metabolic functions. Plant cells have a cell wall as their outer covering like cell membrane is found in the animal cells. Cell Membranes and cells walls can be said to serve the same function as the city walls do in a city. These city walls are the only entrance to the city which are being guarded by several authorities. Likewise in cell membranes there are authorities which are maintaining its integrity. Proteins, lipids and carbohydrates are serving the function of these city authorities in the cell membrane. The main components of the cell membrane are the lipids and the proteins with the proteins forming a major component of the membrane. Fifty five percent of the cell membrane is constituted by proteins. That is for approximately fifty molecules of lipids, there is one protein molecule present. The proteins have a very important role to play in maintaining the shape of the cell membrane which is crucial for maintaining the form and working of the cell as well. Similarly in cities if these authorities let everyone enter the city then the integrity of the city can be put at stake. Proteins also have the ability to work as pumps for the passage of ions by the process of active transport which works against the normal diffusion gradient. They also act as carriers and work in moving substances by the process of facilitated diffusion which involves the movement of secondary substances in association with proteins for the purpose of transport. Glycolipids and glycoproteins also fulfill the functions of the authorities in the city (1; 2; 7). Cytoplasm Cytoplasm is a fluid like substance inside the cell which has many proteins, electrolytes and glucose. It has different organelles embedded in it which function together to perform the city functions. Cytoplasm in a real city can be referred to as the land where different authorities are working together. When someone builds places on the land then the spaces of the land become hidden to anyone’s view and the same happens with the cytoplasm in which the organelles take the role of the places built in the city (3; 5; 7). Endoplasmic Reticulum The endoplasmic reticulum is a broad vesicular structure which contains of the endoplasmic matrix. Substances from different parts of the cell enter the endoplasmic reticulum and are then conducted to other parts of the cell. Endoplasmic reticulum can be divided into the rough endoplasmic reticulum or smooth endoplasmic reticulum. The rough endoplasmic reticulum consists of ribosomes whereas the smooth consists of no ribosomes. The endoplasmic reticulum can be compared to the city roads and highways in a city which connect different parts of the city. It helps in the transportation of essential goods for packaging in factories and endoplasmic reticulum is completing the same task (1; 2; 6). Ribosomes Ribosomes can be found in two forms in the cell. They can be either in a free form or attached to the endoplasmic reticulum. Ribosomes play an important function of synthesizing proteins in the cells. On the endoplasmic reticulum the mRNA comes with the genetic code of protein which is then translated with the help of rRNA. Thus they help in the synthesis of proteins and this can be compared to labor in the city. Labor is done either in an organized form of shops or freely and similar is the case of ribosomes. They can also be compared to the manufacturing plant of the factories as they are manufacturing proteins. The manufacturing plant in the city helps in manufacturing goods which are then processed further. These ribosomes then provide the proteins to the endoplasmic reticulum so that they can transport it. Similarly the goods in the city can be transported by highways or endoplasmic reticulum to factories and packaging plants (1; 2; 6). Golgi Apparatus The Golgi Apparatus is related to the endoplasmic reticulum and is a membranous structure. The products from endoplasmic reticulum are transported to Golgi apparatus and are then packaged in the Golgi apparatus. In conclusion Golgi apparatus is an organelle which packages the products and provides the end products to the cell. It can thus be referred to as a packaging plant of the factory in a city. The products from the manufacturing plant reach the packaging plant so that they can be further processed to form a finished product (1; 2; 6). Lysosomes Lysosomes are cellular organelles which are formed from the Golgi apparatus. The lysosomes contain enzymes which help in digestion and hydrolysis of the waste products in the cells. The lysosomes are surrounded by a membrane which does not let go off the enzymes inside it which would otherwise cause destruction. These lysosomes can be compared to the waste disposal factories in the city which help in the disposal of unwanted products in the city. The lysosomes form products which are then either excreted or recycled by the cell as per their use. Similarly waste disposal factories either recycle or dispose the products entirely from the city (1; 2; 6). Peroxisomes They are vesicular organelles closely linked to the lysosomes. They contain a different set of enzymes known as peroxidases which help in the waste disposal from the cell. Thus they can also be considered to be the waste disposal factories (1). Cytoskeleton The cytoskeleton is the structure which is supporting the whole cell. This cytoskeleton is formed by filamentous structures known as microtubules and microfilaments. They can be compared to steel girders inside the city which are supporting the buildings in the city (1). Mitochondria Mitochondria are the powerhouses of the cells which are double membrane organelles inside the cell. They can range from a few to a thousand depending upon the energy requirement of the cell. It has an outer membrane and an inner membrane which shows infoldings known aas the cristae. It is in the outer membrane that the complex process of electron transport chain occurs to provide Adenosine Triphosphate for energy. Mitochondria in the city can be compared to power houses as they are producing power to run the whole city. It is because of these cells that the people in the city are able to exist. Similarly mitochondria is completing the same function inside the cell by providing energy to the organelles so that they can perform their function successfully (1). Chloroplasts Chloroplasts are organelles inside the plant cells which use solar energy to produce energy inside the cell. It is because of chloroplasts that the plant cells can perform the complex function of photosynthesis. It is the same as mitochondria in the city as it is producing energy for the cell. Thus chloroplasts also function as power plants in the city (4; 5). Vacuoles Vacuoles are membranous sacs located inside the plant cell which are composed of different products. They help to maintain the osmolality inside the plant cell and hence can be referred to as a warehouse in a city. Anything which is in excess is then transferred to vacuoles inside the plant cell and similar is in the city with warehouses. Any excess of materials is usually found in warehouses (4; 5). Nucleus The nucleus is known as the control center of the cell. It is composed of proteins known as histoens around which the DNA is coiled. It sends out signals in the form of RNA to the outer organelles of the cells to perform specific functions to maintain the regularity of the cell. Nucleus can thus be referred to as the control center in the city which is the mayor himself. The mayor gives out orders to different authorities in the city which function in collaboration with the mayor to form a perfect city (4; 5; 1). Conclusion Cell is a basic and functional unit in a living organism which is working like an organized city to fulfill the functions of the body. The organelles in the cell are very important when considering its functions as it is because of them that a cell can function like an organized city. Bibliography 1. Hall, J. E., & Guyton, A. C. (2006). Guyton & Hall physiology review. Philadelphia: Elsevier Saunders.Top of Form 2. Barrett, K. E., & Ganong, W. F. (2010). Ganong's review of medical physiology. New York: McGraw-Hill Medical. 3. Murray, Robert K. (2009) Harper's Illustrated Biochemistry. New York: McGraw-Hill Medical. 4. Cell Structure, a comparison of eukaryotic and prokaryotic cells by Joanne Stafferton 2007 5. Alters, Sandra, and Brian Alters. Biology: Understanding Life. Hoboken, N.J.: John Wiley & Sons, 2006. 6. SHERWOOD, LAURALEE. (2006). Sherwood's Human Physiology From Cells to Systems. Brooks/Cole Pub Co. 7. BERNE, R. M. (1998). Physiology. St. Louis, Mosby. 8. Bottom of Form Top of Form 9. Top of Form Top of Form 10. 11. 12. Bottom of Form Top of Form Bottom of Form Read More