The cell is the smallest structural and functional unit of living things. From butterflies to kangaroos, from a palm tree to spruce all made up of cells. No living creature that is composed of a single cell, called a unicellular organism, and no living thing is composed of more than one cell, called organism multiseluler.Sel despite having a very small size, the cells classified as extraordinary. Why? Cell like a factory that constantly work in order for life to continue. There are parts of cells that function to produce energy, there are responsible for cell proliferation, and there are parts that selects the traffic of substances into and out of cells.
By studying components of the cell, we will be able to understand the functioning of cells for life.
Cells were first discovered by Robert Hooke (who lived in 1635-1703). Hooke (in 1665) observed the cork cells using a simple microscope. It turns out the cork cells look like small rooms. Then, chosen from the Latin word meaning cellula small rooms to name the object he found it.
HISTORY OF CELLS
The cell is the smallest unit in a living organism, both in the world of plants and animals. Cell consists of protoplasm, ie, the cell contents are encased by a membrane or the cell membrane.
The evolution of science are often in parallel with the discovery of equipment that expands the human senses to be able to enter new limits. The discovery and preliminary assessment of the cell to make progress INline invention and refinement of the microscope in the seventeenth century. So the microscope since the beginning of history can not be separated from that of the cell, which is described as follows:
• Galileo Galilei (Early 17th Century) by means of two lenses illustrate the thin structure of insect eyes. Gallei actually not a biologist first recorded observations of biology through a microscope.
• Robert Hook (1635-1703) saw a picture of a thin slice of cork a kompertemen or spaces called by the Latin name cellulae (small room), the origin of the name of the cell.
• Anton van Leeuwenhoek (October 24, 1632 - August 26, 1723), using lenses remedy saw mixed spermatozoa, bacteria and protists.
• Robert Brown (1733-1858) in 1`820 designing lenses that could focus more on observing cells. Opaque point that always exist in the egg cell, the pollen cells, the cells of the tissue growing orchids. Opaque point called the nucleus.
• Matthias Jacob Schleiden in 1838 found there was a close relationship between the nucleus and cell development.
• Teodor Schwan (1810-18830): Cells are part of the organism
theory SEL
A unit cell is the Life. * All objects Good Life Animals OR plants prepared by the cell. Singer cells congregate And their Joining WITH BETWEEN Materials for review such cells form a network such as muscle, cartilage and nerves.
In some circumstances Certain Join Networks and fostering organs like glands, blood vessels, skin dal others.
In nature kita singer Ke cells can be split hearts prayer group, ie prokaryotic and eukaryotic cells. The term prokaryotic, built from pro Dan karyon said. Pro, meaning BEFORE And Kryon, meaning the core. So prokariotiiik cell Artiya "BEFORE core".
The singer implies that instead of eukaryotic cells, without the core, but have genetic material sitplasmanya The scattered hearts. Eukaryotes built Of Eu da Karyon said.
Eu, Means Really Means And karyon core. So the eukaryotic cell is a cell That has had a cell nucleus, OR cell core material Yang Yang had a hearts organized membrane, so that the cell nucleus appears obvious (Sumardi And Marianti, 2007).
It is known that the biota ALL Life on Earth originated from a single cell Now Yang was born 3,500 millions Years Ago. Singer primordial cell membranes are described WITH A Next Affairs, prayer One Event The tricky thing led Determination differences Life on Earth.
The simple organic molecules might has produced hearts Conditions That enabled Life and sustainable earth hidpunya hearts Initial Status (roughly during the first year billions).
• prokaryotes
Which fall within the category prokaryotic cells are bacteria and blue-green algae or cyanobacteria.
On the inside of the bacterial plasma membrane are cytoplasm, ribosomes and nucleoid. The cytoplasm may contain vacuoles, vesicles (small vacuoles) and backup menyimpa sugar complexes or organic materials. Ribosomes are free in the cytoplasm and the site of protein synthesis.
• eukaryotic cells
Eukaryotic cells have developed lebh structure of the prokaryotic cells. Cells are generally seen as jenih mass with an irregular shape, bounded by sutu membrane and down the middle of building a paler artifacts that are round, called nnukleus or the cell nucleus.
So in general it was fostered by the cell membrane or the cell membrane, plasma cells, and the cell nucleus. Below can be seen the structure of eukaryotic cells (animal cells and plant cells).
Plasma membrane (plasmalemma)
Ie membranes or membrane cells located outermost is composed of chemical compounds Lipoprotein (a combination of fatty compounds or compounds Lipids and Proteins).
Lipoprotein is composed of 3 layers when viewed from the outside in order are:
Protein - Lipid - Protein Þ Trilaminer Layer
Fats are Hidrofebik (insoluble in water) while protein is Hydrophilic (water-soluble); therefore the plasma membrane is Selectively Permeable or Semi Permeable (theory of Overton).
Selectively permeable means can only enter / skipped certain molecules.
The function of the plasma membrane is organized transport of substances from one cell to another cell.
Special on tumbahan cells, in addition to having the plasma membrane there is still one more structure that is located outside the plasma membrane is called cell wall (Cell Wall).
The cell walls are composed of two layers of cellulose compounds, in between two layers of cellulose was contained cavity called Middle Lamel (Middle Lamel) that can be filled by substances such as Lignin amplifier, Chitine, pectin, Suberine and others
In addition to the plant cell walls sometimes are gaps that called Node. In Node / Pit often there penjuluran cytoplasm called plasmodesma whose function is similar to nerve function in animals.
The cytoplasm and organelles Cell
The fluid part in the cell cytoplasm called specifically for the fluid that is in the cell nucleus is called nucleoplasm), being part of a solid and has a specific function is used organelles Sel.
The main constituent of the cytoplasm is water (90%), serves as a solvent of chemical substances as well as the media reaction cell kirnia.
Cell organelles are solid objects contained in the cytoplasm and are living (running the functions of life).
A. Cell Wall
Plant cells separated by cell walls that transparan.Dinding cell is outside the plasma membrane structure which limits the space for the cells to swell. The cell walls are characteristic owned plants, bacteria, fungi (mushrooms) and algae, although the compiler structure and completeness.
Cell wall
causing the cells can not move and grow freely, like animal cells. However, this is a positive result because the cell walls can provide support, protection and filters (filter) for the structure and function of the cells themselves. The cell walls prevent excess water that goes into the cell.
The cell walls are made of many different components, depending on class of organisms. In plants, cell walls are formed by a largely carbohydrate polymers (pectin, cellulose, hemicellulose, and lignin as an essential constituent).
In bacteria, peptidoglycan (a glycoprotein) developed cell walls. Fungi have cell walls composed of chitin. Meanwhile, the algae cell walls formed from glycoproteins, pectin, and simple saccharides (sugars) .B. vacuole
Vacuole is a space in a cell containing a liquid (cell sap in English). This fluid is water and various substances dissolved in it. Vacuole found in all plant cells but is not found in animal cells and bacteria, unicellular animals except at low levels.
In the mature leaf cells, vacuole dominates most of the space cell so the cell is often seen as an empty space because the cytosol pushed to the edge of the cell.
For plants, the vacuole plays a very important in life because defense mechanisms depend on the ability of the vacuole to maintain the concentration of substances dissolved in it. The process of withering, for example, occur because of vacuoles lose turgor pressure on the cell wall.
In the vacuole also collect most of the ingredients are harmful to the metabolic processes within cells because plants do not have such effective excretion system in animals. Without the vacuole, the life of the cell will cease because there is chaos reaction biokimi
C. plastids
Plastids are organelles in plant cells (in a broad sense, Viridoplantae). This organelle is best known in its most common form, chloroplasts, as the meeting place of photosynthesis. In fact, the plastids are known in various forms:
• proplastida, form yet "mature"
• leukoplas, adult form without containing pigment, found primarily in the roots
• chloroplasts, which contain the active form of the pigment chlorophyll, found in the leaves, flowers, and parts of other green
• kromoplas, the active form containing pigment carotene, found mainly in flowers and other parts of orange
• amiloplas, semi-active shape containing grains of starch, found in plant parts that store energy reserves in the form of flour, such as roots, rhizomes and stems (tubers) and seeds.
• elaioplas, semi-active shape containing droplets of oil / fat in the oil storage networks, such as endospermium (seed)
• etioplas, semi-active form which is a form of adaptation to the environment chloroplasts less light; etioplas can be immediately activated by forming the chlorophyll in just a few hours, so it gets pretty lighting.
Plastids are vital organelle in plants. Its function is as a place of photosynthesis, the synthesis of fatty acids, as well as some of the daily functions of the cell.
In the evolution of plastids considered a symbiotic prokaryotes into eukaryotic cells and then lose the properties of full autonomy. Endosymbiosis theory is similar to what happened to the mitochondria, but the introduction of the plastids is considered to occur more later.
D. Chloroplasts
The chloroplast is a plastid or chloroplast containing chlorophyll. Takes place in the chloroplasts light phase and the dark phase of the photosynthesis of plants. Chloroplasts found in almost all plants, but are not common in all cells. If there is, then each cell can have one to many plastid. In higher plants generally like discs (approximately 2 x 5 mm, sometimes larger), are arranged in a single layer in the cytoplasm but the shape and position change according to the light intensity.
In algae, can be like a bowl shape, spiral, stars resemble nets, often accompanied pirenoid.
Chloroplasts mature in some algae, biofita and likopoda can multiply by division. Continuity chloroplast occurs through the growth and division proplastid in the meristem.
Typically adult chloroplasts includes two outer membrane menyalkuti homogeneous stroma, this is where the reactions take place dark phase. Stroma embedded in a number of grana, each consisting of a stack of thylakoids in the form of bubbles membranous, flat and discoid (disc-like). Thylakoid membranes of photosynthetic pigments store and the electron transport system involved in this phase of photosynthesis is dependent on light. Grana typically associated with lamella intergrana free pigments.
Photosynthetic prokaryotes do not have chloroplasts, thylakoids that a lot of it is free in the cytoplasm and has a composition that varies with diverse forms anyway. The chloroplasts contain DNA synthesis machinery circumference and protein, including prokaryotic ribosomes type.
Chloroplasts Chloroplasts structure consists of two major parts, namely the envelope and part dalam.Bagian chloroplast envelope consists of outer membrane that is highly permeable, membrane in which is permeable and is attached to a transport protein, and the space between the membrane that lies between the outer membrane and the inner membrane.
The inside chloroplasts contain DNA, RNAs, ribosomes, stroma (the scene of the dark reaction), and granum. Granum consists of thylakoid membrane (where the light reaction) and thylakoid space (the space between the thylakoid membrane). In C3 plants, located in the chloroplasts of mesophyll cells. Examples of C3 crops are rice (Oryza sativa), wheat (Triticum aestivum), soybean (Glycine max), and potato (Solanum tuberosum). In C4 plants, chloroplasts lies in mesophyll cells and bundle sheath cell. Examples of C4 plants are maize (Zea mays) and sugarcane (Saccharum officinarum).
The chloroplast genome of chloroplasts in higher plants is an evolution of photosynthetic bacteria into the plant cell organelles. Chloroplast genome consists of 121 024 pairs of nucleotides and has inverted repeats (2 copies) containing rRNA genes (16S and 23S rRNAs) for the formation of ribosomes.
Chloroplast genome has a large subunit that is encoding ribulose biphosphate carboxylase. Proteins involved in the chloroplasts of 60 proteins. 2 / 3nya expressed by genes contained in the cell nucleus while 1 / 3nya expressed from the chloroplast genome.
E. nuclei
These nuclei are generally most noticeable in eukaryotic cells. The average diameter of 5 lm. Nucleus has a membrane that covers it called membrane or sheath core. This membrane separates the contents of the nucleus to the cytoplasm.
Membrane or sheath core is a double membrane. Both of these sheaths each a lipid bilayer with associated proteins. This membrane perforated by several pore diameter of about 100 nm. On the lips of every pore in the membrane and outer membrane of the nuclear envelope together. These pores allow the relationship between nucleoplasm (liquid core) to the cytoplasm (cell fluid).
In addition to the pore, the inside of the casing is coated with a composition similar to the nuclear lamina webs consisting of protein filaments that maintain the shape of the nucleus nukleus.Di are:
(1). Nucleoli (kids nucleus), serves to synthesize a wide variety of molecules of RNA (ribonucleic acid) used in the assembly of ribosomes. RNA molecules are synthesized passed through the nuclear pores into the cytoplasm, then all joined to form ribosomes. Nucleoli berentuk like a ball, and memalui electron microscope nucleolus is seen as a mass of dark-colored granules and fibers that attaches to the chromatin.
(2). Nucleoplasm (liquid core) is a substance composed of protein.
(3). Granular chromatin, which is contained in the nucleoplasm. It was clear at the time the cell is not dividing. By the time a cell divides chromatin granules thickened into thread-like structures called chromosomes. Chromosomes contain DNA (dioksiribonukleat acid), which works convey genetic information through the synthesis protein.Secara general, Nucleus charge of controlling the activities going on in the cytoplasm. DNA contained in the chromosomes is the blueprint for the formation of various proteins (particularly enzymes). Enzymes are required in carrying out various functions in the cytoplasm.
F. endoplasmic reticulum
The endoplasmic reticulum (ER, or endoplasmic reticula) is an organelle that can be found in all cells of the endoplasmic eukariotik.Retikulum part consisting of a cell membrane system. In the vicinity of the endoplasmic reticulum is called the cytoplasm or cytosol cytosol. Endoplasmic reticulum itself consists of empty rooms are covered with a membrane with a thickness of 4 nm (nanometer, 10-9 meters). These membranes are directly related to the nucleus or nuclear envelope.Pada blanket parts of the endoplasmic reticulum particular, there are thousands of ribosomes or ribosome. The ribosome is the place where the process of protein synthesis occurs in the cell. This section is called the rough endoplasmic reticulum or Rough endoplasmic reticulum. Usability than the rough endoplasmic reticulum is to isolate and bring these proteins to other cell parts. Most of these proteins are not required cells in large quantities and would normally be removed from the cell. Examples of these proteins are enzymes and hormones.
While parts of the endoplasmic reticulum, which is not covered by the ribosomes is called smooth endoplasmic reticulum or Smooth endoplasmic reticulum. Its purpose is to form fat and steroids. The cells are largely made up of smooth endoplasmic reticulum found in several organs such as the endoplasmic hati.Retikulum have a structure that resembles a multi-layered sac. These sacs called cisternae. The function of the endoplasmic reticulum varies, depending on its type. The endoplasmic reticulum (ER) is a maze so much so that the membrane of the endoplasmic reticulum melipiti more than half the total membrane in eukaryotic cells. (Endoplasmic word meaning "within the cytoplasm" and reticulum is derived from the Latin word which means "network").
Another understanding states that the RE as an extension of interconnected membrane channels formed flat or tube-like hole in the sitoplsma.Lubang / channel that helps the movement of substances from one part of the cell to the cell lainnya.Ada three types of endoplasmic reticulum: rough ER On the surface of the RER, there are spots that are ribosomes. Ribosomes play a role in protein synthesis. Thus, the main function of the RER is a site of protein synthesis. RE RE subtle contrast of rough, smooth ER has no ribosomes spots on its surface. RE smooth functioning in several metabolic processes that lipid synthesis, carbohydrate metabolism and calcium concentration, drug detoxification, and attachment of receptors on cell membrane proteins. RE RE sarcoplasmic sarcoplasmic is a special type of smooth ER. RE sarcoplasmic is found in smooth muscle and striated muscle. What distinguishes RE sarcoplasmic from smooth ER is the protein content. Smooth ER synthesizes molecules, while storing and pumping RE sarcoplasmic calcium ions. RE sarcoplasmic role in triggering the contraction otot.RE smooth functioning in various metabolic processes, trmasuk lipid synthesis, carbohydrate metabolism, and offers the drugs and poisons "RE serves as a means of transport of substances within the cell itself".
Endoplasmic nets is a network of tiny pieces scattered freely between the lining membrane throughout the cytoplasm and forming a channel carrier material. These nets are usually associated with the ribosome (red dots) consisting of proteins and nucleic acids, or RNA. The particles had synthesize proteins and to take orders through the RNA (Time Life, 1984) .So RE function is to support protein synthesis and distribute genetic material between the nucleus to the cytoplasm.
Endoplasmic reticulum function
Calcium became a storage place, when the cells contract, the calcium will be excluded from the RE and headed to the cytosol
• Modifying a protein synthesized by ribosomes to be channeled to the Golgi complex and eventually expelled from the cell. (Rough)
• Synthesize fat and cholesterol, this occurs in the liver (rough and smooth ER)
• Neutralize toxins (detox) eg RE is in the liver cells.
• Transportation molecules and parts of cells that one to the other parts of the cell (rough and smooth ER)
G. Ribosomes
Ribosomes are small organelles and dense in selyang functions as a protein synthesis. Ribosomes about 20 nm in diameter and composed of 65% ribosomal RNA (rRNA) and 35% ribosomal protein (called ribonukleoprotein or RNP). These organelles translating the mRNA to form a polypeptide chain (ie proteins) using amino acids brought by the tRNA in the translation process. Within the cells, the ribosomes are suspended in the cytosol or bound to the rough endoplasmic reticulum, or the membrane of the cell nucleus.
H. centrioles
Centrioles is no membranous organelles that are found only in animal cells. These organelles are small, and it was located near a number of core membrane in upright position between the two. These organelles will separate from each other to form a division spindle during cell division occurs. Sentorom an area composed of two centrioles (a pair of centrioles), which occurs when cell division, which will each have centrioles moves to the poles of the cells that are dividing. In the interphase stage of the cell cycle, there are S phase comprising the steps kromoseom duplication, chromosome condensation, and centrosome duplication.
There are a number of distinct phases in centrosome duplication, starting with G1 wherein a pair of centrioles will be separated by several micrometers. Then proceed with the S, namely sentirol child will begin to form so there will be two pairs of centrioles. G2 phase is the phase when centrioles children newly formed earlier has been elongated. M phase where the latter is the centrioles move to opposite poles division and attaches to the microtubule is composed of threads of spindle.
I. Golgi Apparatus
Golgi apparatus (also called the Golgi apparatus, Golgi complex or diktiosom) is an organelle that is associated with excretion function of the cell, and this structure can be seen using ordinary light microscope. This organelle found in most eukaryotic cells and are commonly found in organs that carry out the function of excretion, such as the kidneys. Every animal cell has 10 to 20 Golgi apparatus, while the plant cells have up to hundreds of the Golgi apparatus. Golgi apparatus in plants is usually called diktiosom.
Golgi body was discovered by an Italian nationality histology and pathology named Camillo Golgi.
some functions of the Golgi body include:
l) The mechanism of diffusion
Diffusion is the process of displacement or movement of molecules of the substance or gas of high concentration to low concentration. Diffusion through the membrane can take place through three mechanisms, namely diffusion (simple difusion), d ifusi through a channel formed by transmembrane proteins (simple difusion by chanel formed), and facilitated diffusion (fasiliated difusion).
Simple diffusion through the membrane lasts for -molekul molecules that move or moves through the membrane is soluble in fat (lipid) that can penetrate the lipid bilayer of the membrane directly. The cell membrane-permeable molecules soluble in fat such as steroid hormones, vitamin A, D, E and K as well as organic materials that dissolve in fat, in addition, memmbran cells are also highly permeable to inorganic molecules such as O, CO2, HO, and H2O , Several small molecules dissolved in the special and specific ions, can pass through the membrane through the channel or channels. These channels are formed from a transmembrane protein, a certain sort of pore diameter which allows molecules with a diameter smaller than the pore diameter can pass through. Meanwhile, the molecule - sized molecules such as amino acids, glucose, and some salt - mineral salt, can not penetrate the membrane directly, but requires protein carrier or transporter to be able to penetrate the membrane.
The process involves the entry of large molecules called transforter facilitated diffusion.
