10. Cytosol :
Cytosol is a “Gelatine” substance within which all the other cell organelles reside or you can say which lies outside the organelles. This is a insoluble components of the cytoplasm. Most of the cellular metabolism occurs here. Cytosol also contains the Cytoskeleton. The proteins within cytosol play an important role in signal transduction pathways, glycolysis, intracellular receptors, and transcription factors. Cytosol contains water, free proteins, ions, Macromolecules and a variety of other substances.
In prokaryotes, all chemical reactions take place in the cytosol.
In eukaryotes, the cytosol forms the surrounding environment of organelles.
In plants, the amount of cytosol can be reduced due to the large central vacuole (tonoplast) that takes up most of the cell interior volume.
Cytoplasm is a collective term for the cytosol plus the organelles suspended within the cytosol.
11. Lysosome:
“The acid hydrolases are hydrolytic enzymes that are active under acidic conditions. The lumen is maintained at an acidic pH by an H+ ATPase in the membrane that pumps H+ into the lysosome.”
Lysosome is a membrane bound bag containing hydrolytic enzymes for intracellular digestion. These enzymes called so because these use water to split chemical bonds. You can find these cells commonly in animal cells.
In white blood cells (bacteria eater) lysosome contents are carefully released into the vacuole around the bacteria and serve to kill and digest those bacteria. Uncontrolled release of lysosomes lead to necrotic cell deat.
Hydrolytic enzymes, are manufactured in the endoplasmic reticulum and modified in the Golgi apparatus. In this enzyme proteins are first created in the Rough Endoplasmic Reticulum. Those proteins are packaged in a vesicle and sent to the Golgi Apparatus. The Golgi then does its final work to create the digestive enzymes and pinches off a small, very specific vesicle. That vesicle is a lysosome. From there the lysosomes float in the cytoplasm until they are needed. Lysosomes are single-membrane organelles.View Here….!
Function:
Break cellular waste products, fats, carbohydrates, proteins, and other large molecules into small molecules by inserting a molecule of water into the chemical bond.
12. Centriole :
Centrioles are tubular in shape on which the chromosomes move during mitosis. Centrioles are made of nine triplets of microtubules. Centrioles typically are not found singly. Two centrioles together (together called the diplosome) form one centrosome & each organized at right angles to the other. Found in the cells of most animals.
When a cell divides, the centrosome replicates itself, forming two centrosomes which move to opposite ends of the cell. Each centrosome then sends out spindles which are supposed to separate the cell’s DNA, differentiating a cell into two copies of itself which can then split into fresh cells. An error during this process can create a mutated cell, which may harmlessly die off or become more malignant, depending on the mutation.
13. Vesicles :
A bubble-like membranous and usually fluid-filled pouch structure that stores and transports cellular products, and digests metabolic wastes within the cell; an intracellular membranous sac that is separated from the cytosol by at least one lipid bilayer.
Vesicles form naturally. The vesicle is separated from the cytosol by at least one lipid bilayer. If there is only one lipid bilayer, they are called unilamellar vesicles; otherwise they are called multilamellar. Vesicles can also fuse with other organelles within the cell.
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8. Golgi apparatus or Golgi Complex
Golgi apparatus is a stack of flattened sacs of unit membrane compartments. You can compare this with series of membranes shaped like pancakes, where molecules are packaged for delivery to other cell components for secretion from the cell. This piled structures of membrane system also called multilamellas.
The membrane surrounds an area of fluid where the complex molecules (proteins, sugars, enzymes) are stored and changed.
You will find ribosomes here because Golgi complex absorbs vesicles from the rough ER.
Functions:
It modifies chemicals to make them functional. Secretes chemicals in tiny vesicles. Stores those chemicals and may produce endoplasmic reticulum. For example: It process proteins targeted to the plasma membrane, lysosomes or endosomes and those that will be formed from the cell and sort them within vesicles.
- Some time proteins secreted by exocytosis (e.g., digestive enzymes).
- It handles all incoming lipids, proteins, etc., and controls their export as well.
- The major processing activity is glycosylation: the adding of sugar molecules to form glycoproteins.
- In plant cells, the Golgi secretes the cell plate and cell wall.
- Golgi Bodies, sorts protein, and packages them into membrane - bound structures, called vesicles. Golgi Bodies are in both plant and animal cells. It produces, stores, and transports proteins.
9. Cytoskeleton
That part of the cytoplasm that remains when organelles and internal membrane systems are removed. It is contained in all eukaryotic cells and recent research has shown it can be present in prokaryotic cells too. It helps the the cell to held variety of cellular organelles in place.
The cytoskeleton is made up of three kinds of protein filaments:
- Microtubules
- Actin filaments or microfilaments
- Intermediate filaments
- Microtubules are hollow cylindrical rods, 20-25 nm in diameter. Microtubules are typically found in all eukaryotic cells. They are composed of subunits of the protein tubulin i.e alpha and beta.Microtubules act as a scaffold to determine cell shape, and provide a set of “routes” for cell organelles and vesicles to move on. Also provide the cell support. Microtubules form the spindle fibers for separating chromosomes during mitosis. They are used for locomotion inside flagella and cilia.
- Microfilaments or actin filaments are thread-like protein fibers solid rods 7 nm in diameter and are active in muscle contraction.Actin is the most abundant cellular protein. Microfilaments’ association with the protein myosin is responsible for muscle contraction and also carry out cellular movements including gliding, contraction, and cytokinesis.
- Intermediate filaments are about 10 nm diameter. These can be abundant in many cells and provide support for microfilaments and microtubules by holding them in place. They are structural components of the nuclear envelope or the sarcomeres.
Different intermediate filaments are:
The Isro will roll-out a rival to Google Earth, the hugely popular online satellite imagery service, by the end of the month.
The project, dubbed Bhuvan , will allow users to zoom into areas as small as 10 metres wide, compared to the 200 metre wide zoom limit on Google Earth.
Bhuvan will use a network of satellites to create a high-resolution, bird’s-eye view of India – and later, possibly, the rest of the world – that will be accessible at no cost online and will compete with Google Earth. If a pilot version passes muster, Bhuvan will be fully operational by the spring. There are also plans to incorporate a global positioning system (GPS) into the online tool.
G Madhavan Nair, the Isro chairman, said: “This will not be a mere browser, but the mechanism for providing satellite images and thematic maps for developmental planning.”
Alex Burmaster, of Nielsen, the web analysts, said: “The amount of time that people spend online is reaching a plateau and websites are battling furiously for attention. Anything that relates to where a person is, saves a user time, and makes the web more relevant — especially geographically — is big news.”
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6. Endoplasmic Reticulum
The term “endo” refers to within the cytoplasm and a reticulum is a network.
ER produce protein and lipid components of most of the cell’s organelles. It form a interconnected irregular network of tubules, vesicles and sacs.
They may serve specialized functions in the cell including protein synthesis, sequestration of calcium, production of steroids, storage and production of glycogen, and insertion of membrane proteins. ER functions as a packaging system. ER works closely with the Golgi apparatus, ribososmes, RNA, mRNA, and tRNA.
ER is of two kinds:
Rough Endoplasmic reticulum and Smooth Endoplasmic reticulum
Rough endoplasmic reticulum gets its name from the presence of ribosomes on its surface for protein synthesis.They are very important in the synthesis and packaging of proteins. The newly synthesized proteins are sequestered in sacs, called cisternae store the complex molecules. As the ribosome builds the amino acid chain, the chain is pushed into the ER. When the protein is complete, the rough ER pinches off a vesicle. That vesicle, a small membrane bubble, can move to the cell membrane or the Golgi apparatus. When the protein is complete, the rough ER pinches off a vesicle. That vesicle, a small membrane bubble, can move to the cell membrane or the Golgi apparatus.
Smooth ER acts as a storage organelle in the cell. It creates and store steroids and ions. It consists of tubules and vesicles that branch forming a network. Because of the lack of Ribosomes it does not involved in protein synthesis. The SER is involved in cholesterol metabolism, membrane synthesis, detoxification,Ca++ storage along with other cellular processes.
It functions in diverse metabolic processes, including the synthesis of lipids, carbohydrate metabolism, and the detoxification of drugs and other poisons. Enzymes in the smooth ER are important to the synthesis of fats, phospolipids, steroids, and other lipids. The enzymes detoxify drugs and other poisons, especially in the liver cells. This makes it easier to flush the toxic out of the body.
7. Mitochondria
Mitochondria are the power house of the cell. These provide energy to cell for movement, division, to produce secretory products,contract etc. Mitochondria composed of modified double unit membrane of protein, lipid. The outer membrane is fairly smooth,but inner membrane infolded to form cristae. They have different shapes depending upon the cell type.
On cristae food (sugar) is combined with oxygen to produce ATP - the primary energy source for the cell.
Glucose + Oxygen ——> Carbon Dioxide + Water + Energy (ATP)
You can say Mitochondria are site of cellular respiration.
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“INDIA With Tricolour on the MOON”
After US, former Soviet Union, Japan and the European Space Agency, India becomes the fifth member of this club who send a spacecraft to moon. Chandrayaan-1 nudges closer to moon, orbiting over its polar regions at 200 km periselene (nearest point from moon) and 7,500 km aposelene (farthest point from moon).
The tricolour was painted on all sides of the 29 kg Moon Impact Probe (MIP) which was attached to the top portion of the main lunar orbiter, Chandrayaan.
Chandrayaan-1 spacecraft successfully hit the lunar surface on November 14th at 20:31 hrs. Hosting of tricolor on the moon on Pandit Jawaharlal Nehru’s Birthday made it more remarkable.
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