· Cells Essay. The life Process of a cell In my report you will learn about the life process of a cell based on the two main functions, metabolism and mitosis. You will learn about the four stages of metabolism: ingestion, digestion, respiration, and excretion, and how the cell completes blogger.comted Reading Time: 4 mins Essay about The Cell. Words14 Pages. The cell is the fundamental structural unit of all living organisms. Some cells are complete organisms, such as the unicellular bacteria and protozoa; others, such as nerve, liver, and muscle cells, are specialized components of multi-cellular organisms. Cells range in size from the smallest bacteria-like mycoplasmas, which are · Essay # 4. Modern Cell Theory: It is also known as cell doctrine or cell principle. Modem cell theory states that: i. The bodies of all living beings are made up of cells and their products. ii. 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 blogger.comted Reading Time: 8 mins
Essay on Cells and their parts - Words | Bartleby
Essay on the Introduction to Cell: The cell is the basic unit of life, essay on cells. The life of all organisms including man starts from a single cell and the body is a consortium of individual cells of specific functions and features working in a coordinated manner. Each cell is an amazing world of several biochemical activities- it can assimilate nutrients, convert these nutrients into energy, carry out specialized essay on cells, and reproduce as necessary.
Even more amazing is that each cell stores its own set of instructions for carrying out each of these activities. The largest known cell is an ostrich egg. There are millions of different types of cells and many organisms such as microscopic amoeba and bacteria are single celled. Microscopes opened up new doors in the field of biology by allowing scientists to gaze essay on cells the cellular world. Credit for the first compound microscope is usually given to Zacharias Jansen, of Middleburg, essay on cells, Holland, around the year Actually, Hooke only observed cell walls because cork cells are dead and without cytoplasmic contents.
At the same time, Anton van Leeuwenhoek pioneered essay on cells invention of one of the best microscopes. Leeuwenhoek was the first to observe, draw, and describe a variety of living organisms, essay on cells, including bacteria gliding in saliva, essay on cells, one-celled organisms cavorting in pond water, and sperm swimming in semen.
Modern ideas about cells appeared in the s, when improved light microscopes enabled scientists to observe more details of cells. The cell theory, or cell doctrine, states that all organisms are composed of similar units of organization, cells. The concept was formally articulated in by Schleiden and Schwann and has remained as the foundation of modern biology.
The following year, Theodor Schwann came to the same conclusion about animals. Their findings are now known as the cell theory. Pasteur carried out experiments to determine how substances like milk and wine became curdled or fermented. Through carefully controlled environments, he proved that exposure to airborne particles caused the change. In other words, he proved that organisms did not arise spontaneously, but had to be provided by some means, essay on cells, in this case in the air.
Amoeba and Paramecium are the most primitive forms of unicellular organisms which are able to perform their activities within the walls of one cell. Human beings are multi-cellular animals, essay on cells. Human body is consisting of different types of cell. The functions of each cell are different. For e. kidney cells are different from nerve cells, Liver cells are different from blood cells and brain cells. Though there are differences between the types of cells they all have some basic characteristics in common which indicate signs of life.
Groups of similar cells essay on cells organised together to form tissues and organs, each of which has special function within the body. Cells of multicellular organisms vary in shape and size. The shape of the cell can be elliptical spherical, rectangular, cylindrical, columnar, triangular, biconcave, biconvex etc.
The shape of the cell is influenced by the environmental and physiological factors. The size of the cells varies but the cells of a particular tissue of a given species are nearly uniform in size, essay on cells.
The number of cells varies from organism to organism. Essay on the Characteristics of Cell: Cells Possess the qualities of all living organisms, some of the characteristics of the cells are as follows:.
The cell has the ability to use oxygen brought from the lungs by the blood. It also removes the gaseous waste product carbon dioxide to the blood for its functions and survival. Cell is a very active unit in which the nourishing food materials eaten by essay on cells are absorbed and assimilated, essay on cells.
The cell is capable of absorbing fluids and dissolved substances directly through the cell membrane. Nutrition is essential for the growth and repair of cells. The food materials like amino acids are used by the cell to synthesize new protoplasm, by which the cell increases in size.
In other words the growth and repair of worn out part of the cell can be possible by proteins. These constructive activities, growth and cell repair are known as anabolic function of the cell. The cell needs energy for its activities like glandular secretion, movement and nervous activity.
Both anabolic and catabolic processes are going on in the cell which is known as metabolism. The cell is able to discharge unused and waste materials through cell membrane. The waste materials resulting from the catabolic processes are eliminated from the cell into the interstitial fluid and then to the blood.
Carbonic acid, essay on cells, the waste materials of the cells are removed from the body as carbon dioxide and other waste materials are eliminated in the form of urine by the kidney. Essay on the Basic Concepts of Cell: Now the basic concepts of cell theory can be summarized in the following statements:. Over time and with the development of the electron microscope, essay on cells theory has continued to evolve. As more and more living material was observed at higher and higher magnifications, much more was learned about cells and the cell theory, leading to the modern cell theory.
The modern cell theory essay on cells the two basic components of the classic cell theory and it includes the following postulates. The cell is structural and functional unit of all living things. When cells divide, the hereditary information they contain, as DNA, is passed from cell to cell. Essay on cells on the Types of Cell: a. Prokaryotic Cells :. Prokaryotes are cells that have no membrane-bound nucleus and instead of having chromosomal DNA, their genetic information is in a circular loop called a plasmid.
Bacterial cells are very small, roughly the size of an animal mitochondrion about 0. The shape of a bacterium is governed by its rigid cell wall. Typical bacterial cells are spherical cocci; singular, coccus ; straight rods bacilli; singular, bacillus ; or essay on cells that are helically curved spirilla; singular, spirillum. Although most bacterial species have cells that are of a fairly constant and characteristics shape, essay on cells, some have cells that are pleomorphic, i.
Cocci tend to be quite small, essay on cells, being only 0, essay on cells. They are usually round, may be oval, elongated or indented on one side. Those cocci that remain in pairs after reproducing are called diplococci. Cocci that remain in chains are called streptococci Streptococcus pyogenes. Another arrangement of cocci is the tetrad, essay on cells of four cocci forming a squire. A cube- like packet of eight cocci is called a sarcinia, Micrococcus luteus, essay on cells, a common inhabitant of the skin, is one example.
Other cocci may divide randomly and form an irregular grape like cluster of cells called a staphylococcus, such as Staphylococcus aureus, cause of food poisoning and numerous skin infections. Bacillus are rod-shaped bacteria and the cylindrical cell may be as long as 20 µm or as short as 0. Certain bacilli are slender, such as those of Salmonella typhi that cause typhoid fever; the agent of anthrax Bacillus anthracisare rectangular with squired ends; others such as the diphtheria bacilli Corynebacterium diphtheriaeare club shaped.
The third major shape of bacteria is the spiral, essay on cells, which can take essay on cells of three forms. Certain spiral bacteria called vibrios are curved rods that resemble commas. Other spiral bacteria called spirilla sing. Those spiral- shaped bacteria known as spirochetes have a thin, flexible cell wall but no flagella in the traditional sence. In addition to the bacillus, coccus and essay on cells shapes, other variations also exist. In the genus Caulobacter, essay on cells, there are appendaged bacteria; members of the genous Nocardia consist of branching filaments; and some Archaea have squire and cluster shapes.
Bacterial cells have a cell wall made up of peptidoglycan. Some bacteria have whip like locomotory structures attached to the cell wall called flagella. Some others also have pilli, short, finger like projections that help the bacteria to attach to tissues, one of the main features necessary for pathogenesis. Bacteria that cause pneumonia, for instance, attach to the tissues of the lung Fig.
Bacteria perform many important functions on earth. They serve as decomposers, agents of fermentation, and play an important role in our digestive system. Also, bacteria are involved in many nutrient cycles such as the nitrogen cycle, which restores nitrate into the soil for plants.
Unlike eukaryotic cells that depend on oxygen for their metabolism, prokaryotic cells enjoy a diverse array of metabolic functions. For example, some bacteria use sulphur instead of oxygen in their metabolism.
Even there are several anaerobic microbes which can survive in the absence of oxygen. Eukaryotes have a distinct membrane bound nucleus and organelles.
An organelle is a small structure that performs a specific set of essay on cells within the eukaryotic cell while in prokaryotes they lack distinct nucleus or organelles. The basic structure of all cells is the same.
All cells have an outer covering called a plasma membrane. The plasma membrane holds the cell together and permits the passage of substances into and out of the cell. With a few minor exceptions, plasma membranes are basically the same in prokaryotes and eukaryotes. The interior of both kinds of cells is called the cytoplasm. Within the cytoplasm of eukaryotes are embedded the cellular organelles.
Both types of cells contain small structures, called ribosomes, the site of synthesis of proteins. Ribosomes are not bounded by membranes and are not considered as organelles. Now on the basis of presence of certain specialized organelles having specific functions like chloroplast, eukaryotic cells are of two types:. One of the primary differences between animal and plant cells is that, the plant cells have a cellulose cell wall. This protects the plant cell wall from osmotic shocks.
A plant cell has to be able to accept large amounts of liquid through osmosis, without being destroyed. Animal cells do not have rigid cell wall Essay on cells.
Biology: Cell Structure I Nucleus Medical Media
, time: 7:22Cells Essay Example For Students - words | Artscolumbia
· Cells Essay. The life Process of a cell In my report you will learn about the life process of a cell based on the two main functions, metabolism and mitosis. You will learn about the four stages of metabolism: ingestion, digestion, respiration, and excretion, and how the cell completes blogger.comted Reading Time: 4 mins Essay on Cells and their parts. Words3 Pages. Cells are some of the smallest organisms around. All living things consist of cells, and yet they are invisible to the naked eye. Cells are the basic structural and functional units of life. Cells are made up of many different parts which allow them to function properly 3. Essay on the Basic Concepts of Cell: Now the basic concepts of cell theory can be summarized in the following statements: i. The cell is the basic unit of life. ii. All living organisms are composed of cells. They may be unicellular or multi- Estimated Reading Time: 8 mins
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