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Biology

Biology. The Molecules of Cells. Carbon and Functional Groups Why is Carbon Important? A. What is Organic Chemistry? The study of carbon compounds is know as Organic Chemistry Organic molecules are molecules that contain carbon. A Look at History

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Biology

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  1. Biology The Molecules of Cells

  2. Carbon and Functional Groups • Why is Carbon Important? A. What is Organic Chemistry? • The study of carbon compounds is know as Organic Chemistry • Organic molecules are molecules that contain carbon

  3. A Look at History • Vitalism (Early 19th Century) Belief in a life force outside the jurisdiction of chemical/physical laws. • It was believed that only living organisms could produce organic compounds. • Mechanism – Belief that all natural phenomena are governed by physical and chemical laws. • Began to synthesize organic compounds from inorganic molecules.

  4. B. Carbon – A Close Look • Has an atomic number of 6, leaving 4 valence electrons. • Forms four covalent bonds. C. Carbon Variations • Length (Ethylene to Fatty Acids) • Shape (Straight Chain, branched, rings)

  5. D. Hydrocarbons • Molecules containing only Carbon and Hydrogen • Major components of fossil fuels. E. Isomers • Compounds with the same molecular formula but with different structures and hence different properties.

  6. II. Functional Groups • Contribute to the molecular diversity of life. • Frequently bonded to the carbon skeleton of organic molecules. • Often determine the unique chemical properties of organic molecules. • Are the regions of organic molecules which are commonly chemically reactive.

  7. III. Macromolecules • A. Polymer Principal • Most Macromolecules are polymers. • Polymer – large molecule consisting of many identical or similar subunits connected together. • Monomer – Subunit or building block molecule of a polymer. • Macromolecule – large organic polymer

  8. B. Four classes of macromolecules 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids

  9. C. Polymers are synthesized by a process know as dehydration synthesis.

  10. D. Polymers are broke apart by a process known as hydrolysis.

  11. IV. Carbohydrates • Fuel and building material. • Organic molecules made of sugars and their polymers. • Monomers are called monosaccharides. • Classified by the number of simple sugars.

  12. Monosaccharides • Simple sugar in which C, H, & O occur in a ratio of (CH2O) • Major nutrients for cells (glucose) • Store energy in their chemical bonds.

  13. B. Disaccharides • A double sugar consisting of two monosaccharides joined by glycosidic linkage

  14. C. Polysaccharides • Macromolecules that are polymers of a few hundred or thousand monosaccharides. • Formed by dehydration synthesis. • Have two functions: energy storage and structural support.

  15. V. Lipids • Insoluble in water • Groups include; fats, phospholipids, and steroids • Fats • Store large amounts of energy (One gram of fat stores twice as much energy as a gram of polysaccharide) • Cushions vital organs in mammals. • Insulates against heat loss.

  16. Two classes of fats; saturated fat and unsaturated fat. • Saturated fat • No double bonds between carbons in fatty acid tail • Most animal fats (Ex: bacon grease, butter) 2. Unsaturated fat • There are double bonds between carbons in fatty acid tail. • Most plant fats (Ex: peanut and olive oil)

  17. B. Phospholipids • Major constituents of cell membranes C. Steroids • Lipids which have four fused carbon rings with various functional groups attached.

  18. VI. Proteins • A macromolecule that consists of one or more polypeptide chains folded and coiled into specific conformations. • Polypeptide chain – polymers of amino acids that are arranged in a specific linear sequence and are linked by peptide bonds. • Are abundant – making up 50% or more of cellular dry weight.

  19. Have many functions • Structural support • Catalysis of biochemical reactions (enzymes) • Transport (hemoglobin) • Signaling (chemical messengers) • Movement (contractile proteins) • Defense against antigens (antibodies)

  20. Amino Acids • Only 20 amino acids make millions of different proteins • Building block molecules of a protein • Consists of;

  21. B. Peptide Bond – a covalent bond formed by a dehydration synthesis reaction.

  22. C. Function is dependent upon structure. • Protein conformation – 3D shape of a protein. • Denaturation – A process that alters a proteins conformation and biological activity. • Transfer to an organic solvent. • Breaking hydrogen bonds, ionic bonds, and disulfide bridges • Excessive heat

  23. 1. Four levels of protein structure. a. Primary structure – unique sequence of amino acids in a protein. b. Secondary structure – regular, repeated coiling and folding of a protein’s polypeptide backbone. i. Two types: Alpha helix and Beta pleated sheets c. Tertiary structure – the three-dimensional shape of a protein. d. Quaternary structure – interactions between several polypeptide chains.

  24. VII. Nucleic Acids • Stores and transmits hereditary information. • Two types – DNA & RNA A. DNA (Deoxyribonucleic acid) • Contains coded information that programs all cell activity • Contains directions for its own replication

  25. DNA continued • Is copied and passed from one generation of cells to another. • In eukaryotic cells, found primarily in the nucleus • Makes up your genes B. RNA (Ribonucleic Acid) • Functions in the actual synthesis of proteins coded for by DNA

  26. C. Parts of Nucleic Acid • Nucleic acid – Polymer of nucleotides linked together • Nucleotide – Building block molecule, made up of;

  27. D. Nitrogenous bases • Two families of bases • Pyrimidine – Six membered ring - Includes: Cytosine (C), Thymine (T), & Uracil (U) 2. Purine – Five membered ring fused to a six-membered ring - Includes: Adenine (A) and Guanine (G)

  28. E. Functions of Nucleotides • Monomers for nucleic acids • Transfer chemical energy from one molecule to another (ATP) • Are electron acceptors in enzyme – controlled redox reactions (NAD) • Each gene contains a unique linear sequence of nitrogenous bases; which in turn code for a unique linear sequence of amino acids in a protein.

  29. F. DNA and Proteins • Can be used as a tape measure of evolution. • More closely related species have more similar sequences of DNA and amino acids.

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