Are Animal Cells Able To Produce Glucose Through Photosynthesis

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Trapped Sunlight	Life on this planet needs a abiding supply of free energy in gild to fight the effects of entropy and the second law of thermodynamics. The well-nigh abundant source of this energy is the sun, where vast amounts of radiant energy are created in the nuclear fusion furnaces. A tiny role of this radiant energy reaches this planet in the form of light, where a tiny office, of a tiny role of this free energy is captivated by plants and converted from lite free energy into chemical energy. This is the process chosen photosynthesis . Pigments in special cellular organelles trap quanta of light energy and convert them to high energy electrons. These high energy electrons are in plow used to move electrons in covalent bonds to a higher free energy land. In this process atoms and bonds in carbon dioxide and water are rearranged and new molecules are created. Quanta of light energy are used to pull electrons in covalent bonds to higher free energy levels where they are stable and stored for futurity use. Ii important molecular products are produced in this procedure; oxygen , which is released into the temper, and 3-phosphoglyceric acid , which is kept inside the cells. All plants create iii-phosphoglyceric acrid (3PG) every bit the first stable chemical molecule in this energy trapping mechanism. This simple, 3-carbon molecule is and so used to make all the other kinds of carbohydrates the plant needs. Monosaccharide sugars are made by combining and recombining all those carbon atoms starting time trapped as 3PG. The virtually abundant and versatile of these monosaccharides is glucose . This versatile molecule then plays many roles in the life of the plant - and the lives of animals that eat them.
Source of Free energy	A primary role for the glucose molecule is to deed equally a source of energy; a fuel. Plants and animals use glucose as a soluble, hands distributed form of chemical energy which tin be 'burnt' in the cytoplasm and mitochondria to release carbon dioxide, water and energy. This free energy is then trapped in the ATP molecule and used for everything from muscle wrinkle to pumping water across jail cell membranes. Single sugar molecules can also be attached to proteins and lipids to modify their biological role as enzymes, signaling molecules and as components of membranes. Very oft the improver of one or more sugar molecules will make the recipient molecule more soluble. Glucose (and other monosaccharides) are very hydrophilic ("water loving"), and this can be a problem. Pure monosaccharides, such as glucose, attract h2o. Any plant (or animal) that tried to store large amounts of glucose would have a serious problem with osmosis. Cells containing large numbers of glucose molecules would exist constantly fighting the incessant movement of water from the outside of the cell to the within. The osmotic pressure would be then smashing that even behind their protective walls, plant cells would have difficulty functioning. 1 way circular this problem is to convert the monosaccharides to polysaccharides. These larger molecules do non accept such a neat osmotic pressure and hence tin be stored with greater safety and fewer problems.
Polysaccharides	Although plant and animal cells make a large number of unlike polysaccharides, for all kinds of roles, the ascendant ones are those made from glucose. Cellulose is a polymer of glucose monosaccharides that plants utilise equally their primary edifice material. Threads of cellulose are jump by hydrogen bonds into bundles of dandy strength and flexibility. These are used past plants to environs each prison cell in a way that protects them from the effects of osmosis and too gives them shape and form. Each plant cell wall, yet, is more than but an inert box. About 0.5 micometers thick, it is a complex of pure cellulose (40% to sixty%), a similar polysaccharide made of pentose sugars, and a special bonding agent chosen lignin. Equally the cells grow, expand, shrink or change their shape, the wall is adjusted and modified appropriately, and when the cell divides, a new wall is formed between the daughter cells. A cellulose-like textile, called chitin, is used by insects and arthropods to stiffen and give grade to their outer exoskeleton, and other complex polysaccharides are used in animals in places where tensile strength is needed. Starch is a polymer of the alternate anomer of glucose and is used by plants as a fashion of storing glucose. Information technology is a major reserve of free energy that tin be chop-chop mobilized as necessary. Near plants cells take stored starch reserves in the form of tiny granules. Within these granules are two kinds of starch; amylose and amylopectin, which differ from one another in the amount of branching taking place in the molecule. Many plants also have specialized regions of starch storage in which parenchymatous cells process and package starch molecules for long-term use. Tubers, such as potatoes, and seeds with their valuable embryos, are both establish structures with high concentrations of stored starch. Mobile animals, such as humans, need energy reserves in much the aforementioned way. A small corporeality of these reserves is in the form of an amylopectin-like molecule called glycogen , which is found in the liver and some muscles. However, carbohydrates similar starch or glycogen only produce almost 4 kilocalories of energy per gram of weight, virtually the same as that for poly peptide. While this kind of efficiency is fine for plants (which don't have to move), it is not enough for animals with their higher metabolic needs. Lipids store about 9 kilocalories of energy per gram, well-nigh twice that of carbohydrates, and then they are the preferred fuel in the creature trunk.
	Glucose has ane nifty advantage, however, it is soluble in h2o and claret and thus easy to distribute around the body. Animals use this simple monosaccharide as a portable source of instant energy, adding and releasing it from the liver if and when it is required. Humans need about 2-3,000 kilocalories of energy per mean solar day (24 hours). When possible, humans try to eat and digest meals with loftier caloric value, such as meat and lipids. But food of this sort is rare and difficult to find (or take hold of!). Plants are a much more readily bachelor (and easy to catch!) source of food, and hence the energy we demand. Carbohydrates from plants, therefore, provide upwards to lxxx% of our energy needs every solar day. Depending on the nutrition of the person, starch can business relationship for 30-l% of this carbohydrate, but in some regions of the earth where rice is the prime number source of starch, it can account for up to 100% of the carbohydrates consumed. Interestingly, cellulose cannot be digested by most animals, including humans. Grass eating animals, such equally cows, must therefore enter into a partnership with micro-organisms that tin interruption the bonds between the glucose molecules in the cellulose. If information technology was non for this partnership, they would starve.
BIO dot EDU © 2004, Professor John Blamire