Wait a second!
More handpicked essays just for you.
More handpicked essays just for you.
theory and history of cell
essay about the deveoplement of cell theory
theory and history of cell
Don’t take our word for it - see why 10 million students trust us with their essay needs.
Recommended: theory and history of cell
Cell Theory
The Cell Theory states that all organisms are composed of similar units of organization, called cells. The concept was formally articulated in 1839 by Schleiden and Schwann and has remained as the foundation of modern biology.
Formulation of the cell theory
In 1838 Theodor Schwann and Matthias Schleiden were talking about their studies on cells. It has been suggested that when Schwann heard Schleiden describe plant cells with nuclei, he was stuck by the similarity of these plant cells to cells he had observed in animal tissues. The two published his book on animal and plant cells the next year. Schwann summarized his observations into three conclusions about cells.
1. The cell is the unit of structure, physiology, and organization in living things.
2. The cell retains a dual existence as a distinct entity and building block in the construction of organisms.
3. Cells form by free-cell formation, similar to the formation of crystals.
We know today that the first two tenets are right, but the third is wrong.
The cell theory include:
1. All known living things are made up of cells.
2. The cell is structural and functional unit of all living things.
3. All cells come from pre-existing cells by division.
4. Cells contains hereditary information whish is passed from cell to cell during cell division.
5. All cells are basically the same in chemical composition.
6. All energy flow of life occurs within cells.
With any theory, its tenets are based upon previous observations and facts. The cell theory is no different being founded upon the observations of many. For the first 150 years, the cell theory was just a structural idea. This stuctural view whish is found in most text books describes the components of a cell and their fate in cell reproduction.
The first time, the author, Rebecca Skloot heard of Henrietta Lacks was during a biology class at a community college. "Everybody learns about these cells in basic biology, but what was unique about my situation was that my teacher actually knew Henrietta’s real name and that she was black" (Zielinski). This first initial encounter would begin the search for the unknown story behind the real woman, whose name no one had really heard of. Henrietta had cancerous cells taken from her that would be known as HeLa cells in science literature; the first human cells to reliably and proliferately be produced in a laboratory. These cells became one of the crucial research materials for health and genetic science studies (such as developing the polio vaccine, cloning. and gene mapping), the foundation of medical research and scientific discoveries worldwide. They were also the impotence to a great deal of controversy due to them being taken without the knowledge or consent of the donor or her family; "enduring nearly 60 years of anguish directly related to the success of the Hela cell line" as stated in a review by Norman Fost (87). He brought light to
Concluding-Theres no better way to compare a cell in an analogy than that of a cell to a submarine. Both are a perfect match made in heaven as they are organized in a fashion that is almost identical. I have come to conclusion that Cornelis Jacobszoon Drebbel the creator of the sub based his exact design of that of a cell...even though Robert Hooke wasn’t born until 1635 and the sub was designed in 1620.
Nick Lane aims to inform his readers about mitochondria by providing several examples of the uses of them. He gives several intriguing examples such as the origins of mitochondria, the possible use of mitochondria in fertility treatments, and how they could potentially be used to identify corpses. Lane provides a detailed background on mitochondria: how they formed a successful symbiotic relationship with eukaryotic cells and how mitochondria and their use for cell-independent energy generation was arguably one of the biggest developments in the evolution of simple eukaryotic cells into complex eukaryotic cells. Lane devotes a large part of the start of Power, Sex, Suicide on what he calls “The Quest for a Progenitor” (what Lane calls an ancestor to the eukaryotic cell). He presents many different theories to how the first eukaryotic cell came to being, to which he then explains his agreement or disagreement in great detail. One particular theory he discusses is the Cavalier-Smith theory of ‘primitive amitochondriates’ which in other words focuses on some very old eukaryotes that according to Lane preceded the eukaryotic merger that resulted in the possible production of mitochondria as well as the origin of complex eukaryotes. The conclusion of part
All the living beings are made up of cells. They contain nucleus, which controls and performs their activities. The cells are divided into the two main categories depending on whether they contain nucleus or not. They are:
Hans Spemann was the next person to make an important discovery in 1902. He attempted to split apart a two-celled embryo of a salamander. He accomplished this task by using a baby’s hair to split th...
For many year, scientists have been researching and experimenting to understand how life on earth began and what was the turning point. Many studies and research were done in order to answer this question. After many years of research, scientists finally discovered the essence of life to be the cell. In order to consider something alive, the cells in the organism should be able to grow, reproduce, have the ability to process information, and carry out chemical reactions (Freeman 1). Even though cells are small, they are very complex and they are the functional unit in the human body. After discovering the cell, scientists wanted to know what is the structure of the cell. Under a microscope, an english scientist by the name of Robert Hooke was able to first observe the cell under a microscope using a part of a tree (Karp 2). Scientists divided cells into two different categories; eukaryotic cells and prokaryotic cells; each category has specific characteristics that defines each kind of cell. For instance, eukaryotic cells have a membrane bound organelle called the nucleus as well as ...
This theory was developed from the combined efforts of many different researchers. Together, Konstantin Mereschkowsky, Boris Mikhaylovich Kozo-Polyansky, Ivan Wallin, and Lynn Margulis are the main researchers whom coined the term “symbiogenesis” referring to the long term, or permanent physical association between “differently named partners” (taxa), or the genesis of new species through the merging of two or more existing species (Margulis). Endosymbiosis and symbiogenesis define hypothetical theories thought to justify the origin of species in addition to the processes of natural selection and random mutation. B.M. Kozo-Polyansky and Lynn Margulis, who very much admired Kozo-Polyansky’s work, both believed symbiogenesis was the major source of innovation for evolution (Margulis). The most well known of the first speculations about the origin of organelles, was Mereschkowsky. He primarily studied the chloroplast and was the first to suggest they were obtained initially from unicellular organisms that had been “enslaved” as endosymbionts. However, his theory was turned ...
The book draws its name from the first essay, "The Lives of a Cell," in which Thomas offers his observations on ecology and the role of cellular activity. He writes that the "uniformity of the earth's life, more astonishing then its diversity, is accountable by the high probability that we derived, originally, from some single cell, fertilized in a bolt of lightning as the earth cooled" (3).
There are many different cells that do many different things. But all of these cells fall into two categories: prokaryotic and eukaryotic cells. Eukaryotic cells contain a nucleus and are larger in size than prokaryotic cells. Prokaryotic cells do not contain a nucleus, are smaller and simpler than eukaryotic cells. Two of their similarities are they both have DNA as their genetic material and are covered by a cell membrane. Two main differences between these two cells are age and structure. It is believed that prokaryotic cells were the first forms on earth. They are considered primitive and originated approximately 3.5 billion years ago. Eukaryotic cells have only been around for about a billion years. There is strong evidence that suggests eukaryotic cells may be evolved from groups of prokaryotic cells that became interdependent on each other (Phenotypic analysis. (n.d.).
Eukaryotic cells have their chromosomes contained in a nucleus. Unicellular orgasisms such as amoebas and yeast, or multi-cellular organisms such as plants and animals consist of eukaryotic cells. Human being consist of approximately 1 billion cells per gram tissue. DNA located in 23 pairs of chromosomes is contained in each cell nucleus. Schleiden in 1838 and Schwann in 1839 made very important discoveries that we consist of cells, and Remark discovered that cells prolifarate through division in 1850. Three decades ago, the molecular mechanisms that regulate the cell cycle and thus cell division was able to be identified. It has been known that these vital mechanisms are conserved through evolution and function in the same way in eukaryotic organisms.
Cells are able to grow and reproduce. Cells reproduce by splitting and passing on their genes (hereditary information) to Daughter cells. The nucleus always divides before the rest of the cell divides. Therefore each daughter cell contains their own nucleus. The nucleus controls the cells activities through the genetic material DNA. The cells in a body are all the same except the gametes they were all made from one cell, the Zygote. This is the cell that was formed when two gametes from your parents fused.
Before the germ cell theory was proposed in any form people believed in a different theory the Miasma theory. This was a theory that disease was acquired from a form of “bad air” given off from decomposing matter. Another theory that was popular was that there was four substances in the body and any imbalance between them would cause disease.
The Cell, 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 multicellular organisms. In another words, without cells we wouldn’t be able to live or function correctly. There are Animal Cells and Plant Cells. In Biology class the other day we studied the Animal Cell. We were split into groups of our own and we each picked a different animal cell slide to observe. My group chose the slide,'; Smeared Frog Blood ';.
This report provides an insight into the differences in the structure of cells and the way that they carry out their internal mechanisms. Cells form the basis of all living things and they are the smallest single unit of life. Cell biology is the study of cells and how they function, from the subcellular processes which keep them functioning, to the