Since cells are small, it can only be seen in the aid of a microscope. Spectacles were made in Europe in the thirteenth century. The first compound (double lens) light microscopes were constructed by the end of the late sixteenth century. By the mid-1600s, scientists began to use microscopes that were handmade to discover.
Robert Hooke, and English microscopist was known to be the first to discover a cell. He cut off a piece of cork and examined it under a microscope. He had actually been examining empty cell walls of dead plant tissue
Anton van Leuwenhoek was a Dutchman who spent his spare time grinding lenses and constructing simple microscopes. He was the first to examine a drop of pond water under a microscope. Under the microscope, he observed "animalcules" that moved back and forth. He also was the first to describe various forms of bacteria from water in which pepper had been soaked. Also, he observed the bacteria from the scrapings of his teeth.
The importance of cells was not realized until the 1830s. Matthais Schleiden concluded in 1838 that differences in the structure of various tissues, plants were made of cells and the plant embryo arose from a single cell.
Theodor Schwann concluded that cells of plants and animals are similar in structure.
The cell theory:
1. All organisms are composed of one or more cells.
2. The cell is the structural unit of life.
3. Cells can arise only by division from a preexisting cell.
The first culture of human cells was obtained from a tumor and was named HeLa cells.
In Vitro: Outside the body. Cells grown in culture are said to be grown in vitro; and studies in vitro; and studies on cultured cells are an essential tool of cell and molecular biologists.
Properties of cells
• Cells are Highly complex and organized
• Cells posses a genetic program and the means to use it
• cells are capable of producing more of them cells
• cells acquire and utilize energy
• Cells carry out a variety of chemical reactions
• cells engage in mechanical activities
• cells are able to respond to Stimuli
• Cells are capable of self-regulation
• Cells evolve
Cellular activities are precise. DNA duplication is an example in which the error rate is less than one mistake every ten million nucleotides incorporated, these are corrected by repair mechanisms that recognize the defects.
The epithelial cells that line the intestine are tightly connected to each other. The apical ends of the cells, which face the intestinal channel, have long processes known as microvilli that facilitate absorption of nutrients. The microvilli are able to project outward from the apical cell surface because they contain an internal skeleton made of filaments that are composed of protein monomers known as actin. In the basal ends, the intestinal cells have large numbers of mitochondria to provide energy for membrane transport processes.
Virtually all chemicals changes taking place in the cells require enzymes.
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Robert Hooke, and English microscopist was known to be the first to discover a cell. He cut off a piece of cork and examined it under a microscope. He had actually been examining empty cell walls of dead plant tissue
Anton van Leuwenhoek was a Dutchman who spent his spare time grinding lenses and constructing simple microscopes. He was the first to examine a drop of pond water under a microscope. Under the microscope, he observed "animalcules" that moved back and forth. He also was the first to describe various forms of bacteria from water in which pepper had been soaked. Also, he observed the bacteria from the scrapings of his teeth.
The importance of cells was not realized until the 1830s. Matthais Schleiden concluded in 1838 that differences in the structure of various tissues, plants were made of cells and the plant embryo arose from a single cell.
Theodor Schwann concluded that cells of plants and animals are similar in structure.
The cell theory:
1. All organisms are composed of one or more cells.
2. The cell is the structural unit of life.
3. Cells can arise only by division from a preexisting cell.
The first culture of human cells was obtained from a tumor and was named HeLa cells.
In Vitro: Outside the body. Cells grown in culture are said to be grown in vitro; and studies in vitro; and studies on cultured cells are an essential tool of cell and molecular biologists.
Properties of cells
• Cells are Highly complex and organized
• Cells posses a genetic program and the means to use it
• cells are capable of producing more of them cells
• cells acquire and utilize energy
• Cells carry out a variety of chemical reactions
• cells engage in mechanical activities
• cells are able to respond to Stimuli
• Cells are capable of self-regulation
• Cells evolve
Cellular activities are precise. DNA duplication is an example in which the error rate is less than one mistake every ten million nucleotides incorporated, these are corrected by repair mechanisms that recognize the defects.
The epithelial cells that line the intestine are tightly connected to each other. The apical ends of the cells, which face the intestinal channel, have long processes known as microvilli that facilitate absorption of nutrients. The microvilli are able to project outward from the apical cell surface because they contain an internal skeleton made of filaments that are composed of protein monomers known as actin. In the basal ends, the intestinal cells have large numbers of mitochondria to provide energy for membrane transport processes.
Virtually all chemicals changes taking place in the cells require enzymes.
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