A disaccharide is a pair of monosaccharides. Three disaccharides shown in Figure 2. As you can tell from their common names, you consume these in your diet; however, your body cannot use them directly.
Instead, in the digestive tract, they are split into their component monosaccharides via hydrolysis. Polysaccharides can contain a few to a thousand or more monosaccharides.
Three are important to the body Figure 2. The body obtains carbohydrates from plant-based foods. Grains, fruits, and legumes and other vegetables provide most of the carbohydrate in the human diet, although lactose is found in dairy products. Although most body cells can break down other organic compounds for fuel, all body cells can use glucose. Moreover, nerve cells neurons in the brain, spinal cord, and through the peripheral nervous system, as well as red blood cells, can use only glucose for fuel.
In the breakdown of glucose for energy, molecules of adenosine triphosphate, better known as ATP, are produced. Adenosine triphosphate ATP is composed of a ribose sugar, an adenine base, and three phosphate groups. ATP releases free energy when its phosphate bonds are broken, and thus supplies ready energy to the cell. More ATP is produced in the presence of oxygen O 2 than in pathways that do not use oxygen.
The overall reaction for the conversion of the energy in glucose to energy stored in ATP can be written:. For instance, some carbohydrate molecules bind with proteins to produce glycoproteins, and others combine with lipids to produce glycolipids, both of which are found in the membrane that encloses the contents of body cells.
A lipid is one of a highly diverse group of compounds made up mostly of hydrocarbons. The few oxygen atoms they contain are often at the periphery of the molecule. Their nonpolar hydrocarbons make all lipids hydrophobic. In water, lipids do not form a true solution, but they may form an emulsion, which is the term for a mixture of solutions that do not mix well. A triglyceride is one of the most common dietary lipid groups, and the type found most abundantly in body tissues. This compound, which is commonly referred to as a fat, is formed from the synthesis of two types of molecules Figure 2.
Fatty acid chains that have no double carbon bonds anywhere along their length and therefore contain the maximum number of hydrogen atoms are called saturated fatty acids. These straight, rigid chains pack tightly together and are solid or semi-solid at room temperature Figure 2.
Butter and lard are examples, as is the fat found on a steak or in your own body. In contrast, fatty acids with one double carbon bond are kinked at that bond Figure 2. These unsaturated fatty acids are therefore unable to pack together tightly, and are liquid at room temperature. Plant oils such as olive oil typically contain both mono- and polyunsaturated fatty acids.
As a group, triglycerides are a major fuel source for the body. When you are resting or asleep, a majority of the energy used to keep you alive is derived from triglycerides stored in your fat adipose tissues.
Triglycerides also fuel long, slow physical activity such as gardening or hiking, and contribute a modest percentage of energy for vigorous physical activity.
Dietary fat also assists the absorption and transport of the nonpolar fat-soluble vitamins A, D, E, and K. A phospholipid is a lipid that forms the plasma membrane in cells Figure 2. The tail end of the molecule is hydrophobic and can interact with oil, and the other head-end is hydrophilic and can interact with water.
This makes phospholipids ideal emulsifiers, compounds that help disperse fats in aqueous liquids, and enables them to interact with both the watery interior of cells and the watery solution outside of cells as components of the cell membrane. A steroid compound referred to as a sterol has as its foundation a set of four hydrocarbon rings bonded to a variety of other atoms and molecules see Figure 2.
According to vitalism, only living organisms — since they possess vital force — would be the only ones capable of producing such compounds. Even Louis Pasteur —, who helped put an end to spontaneous generation theory by his experiments on fermentation and whose work led to the inception of pasteurization, believed that fermentation was a vital action in which only life would be able to.
Vitalism eventually lost its support when modern experiments contested its validity. Vitalists believed that urea was an organic compound in the urine and produced only by living organisms.
The modern definition of organic compounds is no longer based on their source. Rather, an organic compound is one in which the compound contains carbon atoms bound to other atoms via a covalent bond. However, chemists cannot reach into a consensus as to the absolute definition of an organic compound.
Defining an organic compound as any compound containing a carbon atom would include those that are classified as inorganic. Carbon-containing compounds considered as inorganic are the following: carbonate s, cyanides, cyanates, carbides, thyocyanates, carbon monoxide, and carbon dioxide.
Allotropes of carbon e. They are made up of only one type of element, which is carbon, and therefore would fail to be categorized as an organic compound since they are not, in the first place, a compound, but a pure element. Nonetheless, they are of vital importance because all living things are based on these compounds. Examples of organic compounds are carbohydrates , lipids, proteins and nucleic acids. Because living things are comprised of carbon-based compounds they can, therefore, be broken down into smaller, simpler compounds through decomposition when they die.
Originally limited to the study of compounds produced by living organisms, organic chemistry has been broadened to include human-made substances e. Organic chemistry is a highly creative science that allows chemists to create and explore molecules and compounds. Organic chemists spend much of their time developing new compounds and finding better ways of synthesizing existing ones. Organic compounds are all around us.
Many modern materials are at least partially composed of organic compounds. Examples of where you can find organic compounds include agrichemicals, coatings, cosmetics, detergent, dyestuff, food, fuel, petrochemicals, pharmaceuticals, plastics, and rubber.
Biotech involves using living organisms and bioprocesses to create or modify products for a specific use. For example, a biotech company might produce seeds for crops that are disease-resistant, or plants that are drought-resistant. Most consumer products we use involve organic chemistry. Take the cosmetics industry as an example. Organic chemistry examines how the skin responds to metabolic and environmental factors, and chemists formulate products accordingly.
Other examples of everyday products that involve organic chemistry include soaps, plastic goods, perfume, coal, and food additives. Crucial to modern world economies, organic industrial chemistry focuses on converting raw materials e. The removal of water molecules links amino acids to form a protein. The process is called dehydration synthesis, and a by-product of the synthesis is water. The links forged between the amino acids are peptide bonds, and small proteins are often called peptides.
All living things depend on proteins for their existence. Proteins are the major molecules from which living things are constructed. Certain proteins are dissolved or suspended in the watery substance of the cells, while others are incorporated into various structures of the cells. Proteins are also found as supporting and strengthening materials in tissues outside of cells.
Bone, cartilage, tendons, and ligaments are all composed of proteins. One essential function of proteins is as an enzyme. Enzymes catalyze the chemical reactions that take place within cells. They are not used up in a reaction; rather, they remain available to catalyze succeeding reactions. Every species manufactures proteins unique to that species. The information for synthesizing the unique proteins is located in the nucleus of the cell. The so-called genetic code specifies the amino acid sequence in proteins.
Hence, the genetic code regulates the chemistry taking place within a cell. Proteins also can serve as a reserve source of energy for the cell. When the amino group is removed from an amino acid, the resulting compound is energy-rich. Like proteins, nucleic acids are very large molecules. The nucleic acids are composed of smaller units called nucleotides. Each nucleotide contains a carbohydrate molecule sugar , a phosphate group, and a nitrogen-containing molecule that, because of its properties, is a nitrogenous base.
Living organisms have two important nucleic acids. One type is deoxyribonucleic acid, or DNA. The other is ribonucleic acid, or RNA.
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