Post by . : ÷Cakey÷ : . on Sept 23, 2007 19:32:10 GMT -5
Brendan Lune returned to his desk as the first bell rang. This bell would send the students from their lockers to his classroom. He absentmindedly stirred the sugar and milk into his coffee while looking over the sheet he was going to hand out.
The cell is the structural and functional unit of all known living organisms. It is the simplest unit of an organism that is classified as living, and is sometimes called the building block of life. Some organisms, such as bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 10 to the power of 14 cells; a typical cell mass is 1 nanogram.) The largest known cell is an ostrich egg. In 1837 before the final cell theory was developed, a Czech Jan Evangelista Purkyòe observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells. All cells come from preexisting cells. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.
The word cell comes from the Latin cellula, meaning, a small room. The descriptive name for the smallest living biologial structure was chosen by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.
Each cell is at least somewhat self-contained and self-maintaining: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. For example, the cells inside a human lung will take the oxygen out of the breath and transmit it to the blood, while leaving the carbon dioxide which is later exhaled. Other cells take in blood and oxygen to expand/contract (such as muscle cells) and each cell stores its own set of instructions for carrying out each of these activities.
This is an example of a normal animal cell.
1: Nucleolus. This, located inside the nucleus of a cell, produces ribosome components.
2: Nucleus. Basically, the brain of the cell. Instructs the cell in doing its many activities. Also, makes the chromosomes, which give the cell its genetic signature. Takes food/other energy and converts it into rough cellular energy and waste.
3: Ribosome. Assembles protein to be taken to/from the nucleus.
4: Vesicle. Vesicles store, transport, or digest cellular products and waste.
5: Rough Endoplasmic reticulum. The endoplasmic reticulum has many uses: Protein translation, folding, and transport of proteins to be used in the cell membrane , or to be secreted from the cell (e.g., digestive enzymes); sequestration of calcium; and production and storage of glycogen, steroids, and other macromolecules. Basically, transport of energy or waste to/from the cell.
6: Golgi Apparatus. The Golgi apparatus is to process and package proteins and lipids.
7: Cytoskeleton. Cellular "scaffolding" or "skeleton" contained, as all other organelles, within the cytoplasm.
8: Smooth Endoplasmic Reticulum.
9: Mitochondria. Mitochondria are sometimes described as "cellular power plants," because they generate most of the cell's supply chemical energy.
10: Vacuole. Vacuoles are membrane-bound compartments within some cells that can serve a variety of secretory, excretory, and storage functions.
11: Cytoplasm. Cytoplasm is a gelatinous, semi-transparent fluid that fills most cells.
12: Lysosomes. Lysosomes are parts of a cell that contain digestive enzymes. They digest excess or worn out cell components (known as organelles), food particles, and engulfed viruses or bacteria.
13: Centriole. Centrioles, found in most cells except some plants and fungi, help keep cells apart in the anaphase, part of cellular mitosis. This is covered later on.
He sipped at his hot coffee, and smiled. The students, if they thought about it, would easily get this. It was the beginning of a unit, and the most basic one in Biology. Mr. Lune smiled and waited. He couldn't wait to pass on this brilliant knowledge to young children who needed it most.
The cell is the structural and functional unit of all known living organisms. It is the simplest unit of an organism that is classified as living, and is sometimes called the building block of life. Some organisms, such as bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 10 to the power of 14 cells; a typical cell mass is 1 nanogram.) The largest known cell is an ostrich egg. In 1837 before the final cell theory was developed, a Czech Jan Evangelista Purkyòe observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells. All cells come from preexisting cells. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.
The word cell comes from the Latin cellula, meaning, a small room. The descriptive name for the smallest living biologial structure was chosen by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.
Each cell is at least somewhat self-contained and self-maintaining: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. For example, the cells inside a human lung will take the oxygen out of the breath and transmit it to the blood, while leaving the carbon dioxide which is later exhaled. Other cells take in blood and oxygen to expand/contract (such as muscle cells) and each cell stores its own set of instructions for carrying out each of these activities.
This is an example of a normal animal cell.
1: Nucleolus. This, located inside the nucleus of a cell, produces ribosome components.
2: Nucleus. Basically, the brain of the cell. Instructs the cell in doing its many activities. Also, makes the chromosomes, which give the cell its genetic signature. Takes food/other energy and converts it into rough cellular energy and waste.
3: Ribosome. Assembles protein to be taken to/from the nucleus.
4: Vesicle. Vesicles store, transport, or digest cellular products and waste.
5: Rough Endoplasmic reticulum. The endoplasmic reticulum has many uses: Protein translation, folding, and transport of proteins to be used in the cell membrane , or to be secreted from the cell (e.g., digestive enzymes); sequestration of calcium; and production and storage of glycogen, steroids, and other macromolecules. Basically, transport of energy or waste to/from the cell.
6: Golgi Apparatus. The Golgi apparatus is to process and package proteins and lipids.
7: Cytoskeleton. Cellular "scaffolding" or "skeleton" contained, as all other organelles, within the cytoplasm.
8: Smooth Endoplasmic Reticulum.
9: Mitochondria. Mitochondria are sometimes described as "cellular power plants," because they generate most of the cell's supply chemical energy.
10: Vacuole. Vacuoles are membrane-bound compartments within some cells that can serve a variety of secretory, excretory, and storage functions.
11: Cytoplasm. Cytoplasm is a gelatinous, semi-transparent fluid that fills most cells.
12: Lysosomes. Lysosomes are parts of a cell that contain digestive enzymes. They digest excess or worn out cell components (known as organelles), food particles, and engulfed viruses or bacteria.
13: Centriole. Centrioles, found in most cells except some plants and fungi, help keep cells apart in the anaphase, part of cellular mitosis. This is covered later on.
He sipped at his hot coffee, and smiled. The students, if they thought about it, would easily get this. It was the beginning of a unit, and the most basic one in Biology. Mr. Lune smiled and waited. He couldn't wait to pass on this brilliant knowledge to young children who needed it most.
