A cell is a small scale, clearly-stated production unit within a larger factory. This unit has full responsibility for producing a family of like parts or a product. All necessary machines and manpower are enclosed within this cell, thus giving it a level of operational autonomy. Cell Membrane:Shipping/Receiving Department Lysosomes are responsible for breaking down and disposing of waste in the cell similar to how a maintenance crew cleans up and takes out the trash. Proteins:Products The cytoplasm contains the organelles, just like how the factory floor. Oct 14, · This feature is not available right now. Please try again later. Cell to Factory Analogy By Mary Wilson Plant Cell: My teddy bear factory is just like a cell: The Golgi apparatus is like the shipping part of the factory. The Golgi apparatus sends out the finished product to the cell membrane and out of the cell. Limit of Cell Size or Volume 6. Types 7. Compartmentalization for Cellular Life 8. Cell— An Open System 9. Shapes Functions. Essay Contents: Essay on the Definition of Cell Essay on the Discovery of Cell Essay on the Cell Theory Essay on the Modern Cell Theory Essay on the Limit of Cell Size or Volume Essay on the Types of Cells.
In this essay we will discuss about the cell. After reading this essay you will learn about: Definition of Cell 2. Discovery of Cell 3.
Manufacturing Cell Essay
Modern Cell Theory 5. Limit of Cell Size or Volume 6. Compartmentalization for Cellular Life 8. Cell— An Open System 9. Cell is a basic unit of life as no living organism can have life without being cellular because cell is a unit of both its structure and function. All life begins as a single cell. A number of organisms are made of single cells.
They are called unicellular or acellular, e. Amoeba, Chlamydomonas, Acetabularia, bacteria, yeast. Here a single cell is: Anything less than a complete cell cans neither lead an independent existence nor perform all the functions of life. A multicellular organism is made of many cells. A higher animal or plant contains billions of cells. For example, a newly born human infant has 2 x cells.
The number increases to trillion x or cells in the body of 60 kg human being. A drop of blood contains several million cells. The large sized organisms do not have large sized cells. Instead they possess higher number of cells. In multicellular organisms, cells are building blocks of the body or basic units of body structure.
Human body has some types of cells, e. Cells are grouped into tissues, tissues into organs and organs into organ systems. Occurrence of different types of tissues, organs and organ system results in division of labour or performance of different functions of the body by specialised structures.
Cells are not only the building blocks of the organisms, they are also the functional units of life. Life passes from one generation to the next in the form of cells. The activities of an organism are actually the sum total of activities of its cells. A new cell always develops by division of a pre-existing cell. Cells are totipotent, i. Internally each cell is build up of several organelles. The organelles perform different functions just like the ones carried on by different organ systems of the body.
All life activities of the organism are present in miniature form in each and every cell of its body. Thus, cell is a basic unit of life and structural and functional unit of an organism. It is the smallest unit capable of independent existence and performing the essential functions of life. Work on the study of cell has continued for more than the last three and a half centuries.
It required microscopes or instruments with good resolving power and magnification. Improvement in tools and techniques has continued all this period to enhance our knowledge about the cell. The first microscope was built by Zacharias Janssen in It was first modified by Galileo and then by Robert Hooke Fig.
Robert Hooke was a mathematician and physicist. He developed a new microscope with which he studied the internal structure of a number of plants. His work is famous for the study of cork cells. He took a piece of cork of spanish oak and prepared thin slice by means of sharp pen knife.
A deep planoconcave lens was used for throwing light on cork piece. The latter was observed under the microscope. He did not know the significance of these structures and regarded them as passages for conducting fluids. Robert Hooke found that the cells or boxes were not very deep. A cubic inch contained ,, cells, a square inch 1, 66, and one inch strip cells. Cells were also observed prior to Hooke, by Malpighi , who called them saccules and utricles.
Leeuwenhoek was first to observe, describe and sketch a free living cell. He observed bacteria, protozoa, spermatozoa, red blood cells, etc.
Essay on Cell
In the beginning of nineteenth century it became clear that the bodies of organisms are made of one or more cells. Robert Brown discovered the presence of nucleus in the cells of orchid root. Living semifluid substance of cells was discovered by Dujardin and named sarcode.
Schleiden found all plant cells to have similar structure— cell wall, a clear jelly-like substance and a nucleus. Schwann discovered that animal cells lacked cell wall. Purkinje and von Mohl , renamed sarcode or the jelly like substance of the cells as protoplasm Gk. Cell membrane was discovered by Schwann but was provided with a name by Nageli and Cramer Soon various organelles were discovered inside the cells.
Electron microscope has elaborated our knowledge about cells. Formulation of Cell Theory: Development of cell theory illustrates how scientific methodology operates. It involves observation, hypothesis, formulation of theory and its modification. Observations were started by Malthias Schleiden , a German botanist who examined a large number of plant tissues.
He found that all plant tissues were made of one or the other kind of cells. Therefore, he concluded that cells constitute the ultimate units of all plant tissues.
Theodore Schwann , a German Zoologist, studied different types of animal tissues including development of embryos. He found that animal cells lack a cell wall. Instead they are covered by a membrane. Otherwise cells of both plants and animals are similar.
Schwann defined a cell as membrane en-locked, nucleus containing structure. He also proposed a cell hypothesis — bodies of animals and plants are made of cells and their products. The theory proposed that cells are the units of both structure and function of organisms.
Rudolf Virchow observed that hew cells develop by division of the pre-existing cells— Omnis cellula e cellula theory of cell lineage or common ancestry. The finding gave cell theory its final shape. Louis Pasteur further proved that life originated from life. Soon Haeckel established that nucleus stores and transmits hereditary traits. Cell theory was modified accordingly. Fundamental Features of Cell Theory: Five fundamental observations of the cell theory are: All living organisms are composed of cells and their products.
Each cell is made of a small mass of protoplasm containing a nucleus in its inside and a plasma membrane with or without a cell wall on its outside. All cells are basically alike in their chemistry and physiology.
Activities of an organism are the sum total of activities and interactions of its constituent cells. It is also known as cell doctrine or cell principle. Modem cell theory states that: The bodies of all living beings are made up of cells and their products.
Cells are units of structure in the body of living organisms. Every cell is made up of a mass of protoplasm having a nucleus, organelles and a covering membrane.
Cells are units of function in living organisms, that is, the activities of an organism are the sum total of the activities of its cells. While a cell can survive independently, its organelles cannot do so. The cells belonging to diverse organisms and different regions of the same organism have a fundamental similarity in their structure, chemical composition and metabolism.
Life exists only in cells because all the activities of life are performed by cells.
Comparing a Cell to a Factory: Answer Key
Depending upon specific requirement, the cells get modified, e. Growth of an organism involves the growth and multiplication of its cells. Genetic information is stored and expressed inside cells. Life passes from one generation to the next in the form of a living cell.