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similarities and differences between eukaryotic and prokaryotic cells
compare prokaryotic and eukaryotic cells
theories on the origin of life 200-300 words
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Prokaryotic Cells
All living things are made of cells, and cells are the smallest units
that can be alive. Life on Earth is classified into five kingdoms, and
they each have their own characteristic kind of cell. However the
biggest division is between the cells of the prokaryote kingdom
(monera, the bacteria) and those of the other four kingdoms (animals,
plants, fungi and protoctista), which are all eukaryotic cells.
Prokaryotic cells are smaller and simpler than eukaryotic cells, and
do not have a nucleus. Prokaryotic means 'pre-nucleus' and eukaryotic
means 'true nucleus'. The nucleus in eukaryotic cells contains the DNA
in linear chromosomes and is bounded by a nuclear membrane, but since
a prokaryotic cell doesn't have a nucleus and its DNA is a single,
circular coiled molecule that floats freely within the cell and is not
bounded by nuclear membrane nor is it complexed with any proteins. In
addition to the circular DNA some bacteria also contain plasmids.
Prokaryotic cells are far older and more diverse than eukaryotic
cells. Prokaryotic cells have probably been around for 3.5 billion
years, which is about 2.5 billion years longer than eukaryotic cells.
Not all Prokaryotic cells have all the parts shown above. All
bacterial cells have a cell wall, cytoplasm, cell membrane, circular
DNA, food reserve granules, and ribosomes. The capsule (or slime
layer) is a thick polysaccharide layer outside of the cell wall. It is
used for sticking cells together, as a food reserve, as protection
against desiccation and chemicals, and as protection against
phagocytosis. It also sores waste and protects the cell from drying
out. The cell ...
... middle of paper ...
...Do not have chloroplasts
Animal cells don't have chloroplasts but plant
cells do
Do not have endoplasmic recticulum or golgi
body
Do have endoplasmic recticulum and golgi
body
Always unicellular
Often multi-cellular
No cytoskeleton
Always has a cytoskeleton
Cell division is by binary fission
Cell division is by mitosis or meiosis
Reproduction is always asexual
Reproduction is asexual or sexual
Do not have a nucleus or any membrane-bound organelles
Always have a nucleus and other membrane organelles
DNA is circular, without proteins (naked)
DNA is linear and associated with proteins to form chromatin
May have one or more flagella
Have no flagella
Have a protective capsule (or slimy layer)
Do not have a protective capsule (or slimy layer)
Cell cycle events portray some differences between different living things. In all the three living things, their cells divide, a process referred to as mitosis. The mitosis stage differs and it encompasses four phases. During development, the cell cycle functions endlessly with newly created daughter cells directly embarking on their path to mitosis. Bacteria cells separate forming two cells after every thirty minutes under favorable conditions. However, the eukaryotic cells take quite longer compared to bacteria cells to develop and divide. Nevertheless, in both animals and plants, cell cycle is usually highly regulated to prevent imbalanced and excessive growth. Both animals and plants are known as eukaryotes meaning that their DNA exists inside their cells’ nuclei. Therefore, their cells as well as mitotic processes are similar in various ways (Eckardt, 2012).
In the 1960s the HeLa cells were everywhere. In the 1960s the scientist wondered since the cells grew so fast and lived on earth so well if they would live in space. They got the idea to send the Hela cells to space. They sent several vials into space by the Discoverer XVII when it went. They discovered that when the HeLa cells went to space they became more powerful and divided faster every time they went to space. Several years later in 1965 they took equal amounts from the HeLa cells and cells from a mouse. The scientists done this to study to see what the genes would do. Harris also took HeLa cells and chicken cells, but they discovered they couldn’t reproduce.
Eukaryotic Cells are Deemed as a Result of the Evolution of Symbiotic Prokaryotes Both Prokaryotic and Eukaryotic cells over time have sustained very dynamic changes from one another. More specifically we have seen the appearance of a more complicated and organized cell structure, the nucleus. However the big question amongst scientists today is how did these changes first occur? A fundamental concept of this evolution is the belief in the natural progression 'from the simple, to the more complex.' However one popular theory that argues that Prokaryotic symbiosis was responsible for forming the Eukaryotic nucleus is the 'Endosymbiotic Theory' this theory was first proposed by a former Boston University Biologist known as Lynn Margulis in the 1960's.
Title : With the aid of diagrams, compare the structure and function of prokaryotic and eukaryotic cells
In the beginning of the creation of Earth volcanoes erupted all over the planet. During this period there was a time where a brief cooling period was allowed to take place. When this period took place evaporation caused a downpour of rain which flooded the ocean creating the ocean. At the time that ocean was averaged at 3,000 degrees Fahrenheit. Around this same time an asteroid so powerful hit the Earth knocking off a large chunk of it. This chunk became the moon which at the time was twice as close as it is today. The hitting of the planet Earth cause such a shake that many new undersea volcanoes began spewing forth molten rock and gasses. These gasses and other particles formed on the oceans surface and with the moon being so close were smashed together by strong and violent waves.
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 ...
A prokaryote is a basic unicellular cell typically chracterized by having no defined nucleus. Examples of prokaryotes are typically given as orgamins that belong to the Bacteria and Archaea domains (Campbell 13). Furthermore, prokaryotes are very similar to eukaryotes except for the fact that they don't have a nucleous but a nucleoid and that prokaryotes are smaller than eukaryotes (Campbell 98). By the definition of a prokaryote and process of elimination it is easy to find the correct answer which is D.
Every day, I would drag myself to school, do my work, get home, do homework, then go to bed. For years, on and on every single day using the same method, repeating the same pattern. “Go to page 247 in your textbook.” “Find the circumference of the circle provided.” “Identify the organisms as prokaryotic or eukaryotic.” I felt that my life couldn’t get any worse, that everybody had it better off than me. I hated every single hour of the day, every single day of the week. I used to wear a fake mask to make it seem like everything was okay, all was well, when all I was doing was living a lie. Then I read your book, “Finding Spirit Bear”. My english teacher assigned us the book as an assignment for class, which I sped through, just to get it over
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.
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.
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.
There are two main types of cells in the world. The simplest cells such as bacteria are known as Prokaryotic cells, and human cells are known as Eukaryotic cells. The main difference between each of these cells is that a eukaryotic cell has a nucleus and a membrane bound section in which the cell holds the main DNA which are building blocks of life.
Prescott, Harley & Klein (1990) describe bacteria as prokaryotic cells (cells that lack a true membrane enclosed nucleus). Bacteria are both small and simple in structure; they usually are between o.5 and 5cmm yet they have many characteristic shapes and sizes. Some bacteria are circular or oval shaped, they are known as cocci bacteria. Other bacteria are rod-shaped, they are known as bacilli bacteria, and some bacteria are spiral and coil-shaped and it is know as spirilla bacteria.
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 ';.