Cells and Cell Theory
What advantages does small size give to a cell?
Many cellular processes occur by diffusion, which is efficient over short distances, but less efficient over long distances. Since all materials going in and out of a cell must pass through the plasma membrane, the greater the surface area of this membrane, the faster a given quantity of molecules can pass through. Smaller cells have a much greater surface-to-volume ratio than larger cells and therefore can "feed" all areas of the cell in less time.
What is "surface-to-volume ratio," and how does it affect cell size?
The surface-to-volume ratio is a mathematical relationship between the volume of an object and the amount of surface area it has. This ratio often plays an important role in biological structures. Think of a cell as a sphere:
The surface area of a sphere can be calculated by
4ð r2 where r is the radius of the sphere.
Volume of a sphere can be calculated by
4/3 ð r3.
An increase in r will increase the surface area by a power of two, but increase the volume by a power of three. This means that the volume will increase much faster than the surface area. This puts an upper limit on the size of a cell, because if the cell volume gets too big, there won't be enough membrane to transport the amount of food in and wastes out to support that large cell size.
What is the difference between prokaryotic and eukaryotic cells?
Prokaryotic cells are more simple: they are usually much smaller and don't have a nucleus or any other membrane-bound organelles. Bacteria are prokaryotes. Eukaryotic cells are much more complex, are usually larger, and have a nucleus and several other membrane-bound organelles that allow them to compartmentalize their functions. All multicellular plants and animals are eukaryotes. A helpful trick to remember is that "you" are a "eu"karyote.
Are there any single-celled eukaryotes?
Yes--yeast, for example. Yeast are single-celled organisms, but they do contain a membrane-bound nucleus, mitochondria, and other organelles.
What are the advantages and disadvantages of prokaryotic compared to eukaryotic cells?
Although prokaryotes may seem more primitive than eukaryotes, they are among the most successful species on our plant and comprise a very large percentage of the total mass of all living things on earth. Simple, small, and single-celled organisms can reproduce quickly and evolve quickly. Prokaryotes can generate millions of progeny in a short period of time.
to construct and or maintain the cell membrane. In a microscopic view of the cell membrane we can
5. A cell’s shape is related to its function. For example, a long nerve cell is long and it carries messages from your spine to your toes.
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 ...
Kingdom Protista is considered an artificial grouping because there are many forms of protist and most are unicellular, multicellular, and colonial groups. The protists have different functions and structure although they are considered eukaryotes and are still evolving.
As the gelatin cube sizes were cut into smaller pieces, the surface area to volume ratio increases. Surface area to volume ration is very important in living organisms, since all the nutrients and oxygen need to diffuse through the cell membrane into the cells. The surface area to volume ratio affects the rate in which the salt diffused through the solution by how the salt diffused out of the gelatin and into the water this relates to small cells that have a faster rate of diffusion for the nutrients and oxygen to diffuse into the cell and out of the cell quicker. Whereas if the cells were bigger, the rate of diffusion for the nutrients and oxygen to diffuse into the cell would take too long and the cell would probably not survive. So the surface area to volume ratio in cells is vital since the smaller they are the faster the rate of diffusion of the nutrients and oxygen can go in and out for the cell to be able to grow and survive.
* Surface Area - This will not affect any of my results, as we are
The cell is the most basic unit of life, defined as “The fundamental ... structural and functional unit of all living organisms” (Oed.com, 2013). The prokaryotic cell is typically composed of a plasma membrane and cell wall, containing within it the cytosol and a structure known as the nucleoid. This is a single piece of circular or linear DNA that floats freely in the cytosol of the cell (Thanbichler et al., 2005, pp. 507).
A Prokaryote is a single cell organisms that does not have a nucleus, which is divided into two major groups: archaeabacteria and bacteria. Prokaryotes are usually found in three common structures, such as bacillus is rod shaped, crocus is spherical-shaped, and spirillum is long shape. Although there are prokaryotes that are responsible for diseases there are also good types of bacteria that we need. Prokaryotes provide essential services to biological systems for instance food and agriculture.
According to Carl Woese, a professor of microbiology at the University of Illinois, eukaryote cells are more structurally complex than those of their prokaryotic counterparts. Eukaryote evolved from prokaryotic cells as they adapted to their environment. Evidence shows that mitochondria, an organelle found in all eukaryotic cells, are actually the product of two independent bacteria’s becoming one. This process is known as endosymbiosis or teamwork. Some evidence supporting the idea of endosymbiosis follows; the chloroplasts and the mitochondria are similar to bacteria in size as well as structure, both mitochondria and chloroplasts contain limited amounts of genetic material which could be from splitting, and both of these organelles are surrounded by a double membrane which suggest that the out membrane may be derived from the engulfing vesicle, and the inner
- Suface Area: if you are to change the surface area it is going to
The nucleus is often the largest organelle found in a Eukaryotic cell with a size of 10-20 un. It is surrounded by two membrane layers which can be identified on the diagram below. Within the nucleus structure are small pores with a size of 100un in diameter. These pores together make up around one third of the nuclear membrane surface area.
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
The ratio for length to width of rectangles is 1.61803398874989484820. The numeric value is called “phi”.