Living organisms are made up of chemical building blocks : All organisms are composed of a variety of these biological macromolecules. Biological macromolecules play a critical role in cell structure and function. Most but not all biological macromolecules are polymers, which are any molecules constructed by linking together many smaller molecules, called monomers.
Typically all the monomers in a polymer tend to be the same, or at least very similar to each other, linked over and over again to build up the larger macromolecule.
These simple monomers can be linked in many different combinations to produce complex biological polymers, just as a few types of Lego blocks can build anything from a house to a car. Monomers and polymers : Many small monomer subunits combine to form this carbohydrate polymer. Examples of these monomers and polymers can be found in the sugar you might put in your coffee or tea. Regular table sugar is the disaccharide sucrose a polymer , which is composed of the monosaccharides fructose and glucose which are monomers.
Dehydration is the process of creating a bond between two molecules to create a new, larger molecule by taking one hydrogen from one molecule, and an OH from the other, creating one molecule of free water. Why are lipids not considered polymers? Biology Molecular Biology Basics Lipids. Hunt B. Nov 8, Explanation: Polymers are chains of subunit molecules that are all similar in a way that allows the subunits to continue building longer macromolecules on either end.
A large molecule that is composed of two or more monomers is called a polymer. For example, a glucose molecule is a monomer.
When two glucose molecules are attached, they form a true polymer called maltose. One important feature of polymers is hydrolysis, which means that the bonds between monomers break in the water, making the substance soluble. The bonds between glycerol and fatty acids, as well as the sequence of molecules in lipids, is different from monomers. Because of this, lipids are not soluble in water and thus are not considered true polymers.
Millions of free papers! Why are proteins considered polymers but lipids not? Fatty acids form more complex lipid polymers called triglycerides, triacylglycerols or triacylglycerides when each single-bonded oxygen molecule bonds to a carbon that's part of a glycerol molecule. Glycerol is a simple alcohol composed of three oxygen atoms and three carbon atoms that bond with hydrogen atoms eight times.
Triglycerides are also commonly found in foods, especially animal products. When a triglyceride replaces one fatty acid chain with a phosphate group, it forms a phospholipid.
Phosphate groups are made of a phosphorus atom bonded to oxygen atoms. Phospholipids form a characteristic bilayer structure, with water-repellent, or hydrophobic, layers sandwiching a water-permeable, or hydrophilic, middle. They're the primary component of cellular and intracellular membranes. Steroids such as cholesterol, used by the human body to produce hormones and other major components of the nervous system, are not considered true polymers.
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