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T he F our M ajor G roups of O rganic C ompounds: C arbohydrates, L ipids, P roteins, and N ucleic A cids; and T heir F unctions in L iving S ystems. C arbon a M ost V ersatile A tom. -The Carbon atom has 6 protons 6 neutrons 6 electrons
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The Four Major Groups of Organic Compounds: Carbohydrates, Lipids, Proteins, and Nucleic Acids; and Their Functions in Living Systems
Carbon a Most Versatile Atom • -The Carbon atom has • 6 protons • 6 neutrons • 6 electrons • -Carbon has 4 electrons in its outermost energy level, therefore it needs four electrons to complete its octet. • -Carbon covalently shares • electrons with up to four other atoms. This characteristic makes Carbon very versatile when it comes to chemical structures.
Carbon’s Chemical Properties and Molecular Diversity Carbon Skeletons Vary • Carbon chains • Vary in length • May be linear or branched • May contain only c-c single bonds or may contain double and/or triple bonds at various locations • Carbon rings • May contain only single c-c bonds, or may contain double bonds
Functional Groups Confer Specific Properties to Carbon Compounds • Carbon skeletons come in may shapes and forms. These are basically Hydrocarbons (molecules composed of only Carbon and Hydrogen atoms). • Functional groups, have specific properties characteristic to their chemical structure and further add variety to the Hydrocarbon skeleton molecular structures.
Monomers ↔PolymersDehydration ↔ Hydrolysis • Monomers are molecules that are chemically bonded through dehydration synthesis to make polymers, which are the functional macromolecules. • Polymers can be broken down into their monomer components through hydrolysis.
Carbohydrates aka Saccharides Are Aldoses and Ketoses • Carbohydrates have the atomic ratio C:H2O. • They are composed of many monosaccharide (monomers) chemically combined through dehydration synthesis into polysaccharides (polymers). • Glucose C6H12O6 is made by plants and is the most common monosaccharide. • Serve as energy sources for plants, animals and other organisms. Converted into ATP energy. • Serve as structural molecules in plants and other organisms. • Dietary source: plant products. • Cellulose is bulk or fiber.
Lipids Are Hydrophobic • Lipids include: fatty acids, steroids, phospholipids, and waxes. • Because they are not solublein water, they are good structural, insulation, transport, and storage macromolecules, such as: • Adipose tissue • cell membranes components • hormones • triglycerides • oils and waxes
Fatty Acids Are Long Hydrocarbons with a Carboxylic Acid Functional Group • Saturated fatty acids usually come from animal sources and are solid at room temperature, these are high in caloric value. • Unsaturated fatty acids usually come from plant sources and are liquid at room temperature, these are lower in caloric value.
Steroids . A steroid’s structure is composed of carbon rings. . Steroids serve as the structural components of many hormones, such as estrogen and testosterone. . Steroids are essential for maintaining the fluidity of cell membranes. . Diets rich in saturated fats promote accumulation of LDL “bad cholesterol” in the wall of arteries, reducing blood flow and promoting hypertension and the incidence of strokes.
Proteins • Proteins are the structural components of living tissue. They also serve as enzymes, hormones, and immunoglobulins, among many other roles. • Proteins are composed of amino acids (a.a.). We acquire a.a. by consuming meat, fowl, fish, dairy, eggs, legumes, and nuts
Proteins: Composed of Amino Acids • Amino acids are the monomers that are dehydrated to form polypeptides or proteins. • Humans have about 20 different amino acids from which proteins are synthesized. The difference between one protein and another has to do with the number of amino acids that a protein contains and the unique sequences in which the amino acids are arranged. • Protein synthesis occurs in the ribosomes of cells and is controlled by genetic information.
Protein Synthesis: • Amino acids are chemically combined through dehydration synthesis by peptide bonds to form polypeptides (protein) • The sequence of amino acids in a polypeptide is determined by genetic information
Nucleic Acids Have Sugars, Nitrogenous Basesand Organic Phosphate Components • Nucleic Acids serve as information macromolecules, such as DNA and RNA. (We will study these further in the future.) • Another type of Nucleic Acid, ATP, serves as the energy currency of cells. (We will study ATP further in the future.) • Nucleotides (picture at left) are the molecular components of Nucleic Acids.
Structure Is Always Related to Function • Living organisms require thousands of different types of molecules to maintain their structure and sustain their body’s functions. • The ability of Carbon to bond with four other atoms is the basis for the vast variety of chemical structures found in organisms.