Lecture Presentation Chapter 21 Nucleic Acids and Protein Synthesis Karen C Timberlake General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chapter 21 Nucleic Acids and Protein Synthesis A histology technician studies the microscopic makeup of tissues, cells, and bodily fluids with the purpose of detecting and identifying the presence of a specific disease They determine blood types and the concentrations of drugs and other substances in the blood General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chapter Readiness Core Chemistry Skills • • • Forming Amides (18.5) Drawing the Zwitterion for an Amino Acid (19.1) Identifying the Primary, Secondary, Tertiary, and Quaternary Structures of Proteins (19.4, 19.5) • Identifying Factors Affecting Enzyme Activity (20.3) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc 21.1 Components of Nucleic Acids The general structure of a nucleotide includes a • • • nitrogen-containing base sugar phosphate group Learning Goal Describe the bases and ribose sugars that make up the nucleic acids DNA and RNA General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Nucleic Acids There are two types of nucleic acids: • deoxyribonucleic acid (DNA), which may contain several million nucleotides, and ribonucleic acid (RNA), which may contain several thousand nucleotides • both are unbranched polymers of repeating monomer units known as nucleotides Each nucleotide has three components: • • • a base that contains nitrogen a five-carbon sugar a phosphate group General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Bases The bases in DNA and RNA are • • • • derivatives of the heterocyclic amines pyrimidine or purine pyrimidines with a single ring containing two nitrogen atoms purines with two rings, each containing two nitrogen atoms + H acceptors at the nitrogen atoms in each base General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Bases in DNA In DNA, • the purine bases with double rings are adenine (A) and guanine (G) • the pyrimidine bases with single rings are cytosine (C) and thymine (T) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Bases in RNA In RNA, • the purine bases with double rings are adenine (A) and guanine (G) • the pyrimidine bases with single rings are cytosine (C) and uracil (U) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Pentose Sugars The five-carbon sugar • • in RNA is ribose in DNA is deoxyribose, with no O atom on C2′ • has carbon atoms numbered with primes to distinguish them from the atoms in the bases General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Nucleosides A nucleoside • is composed of a nitrogen-containing base and a sugar, either ribose or deoxyribose • has a base linked by a β-N-glycosidic bond to C1′ of a sugar (ribose or deoxyribose) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Diseases Caused by Viruses General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Reverse Transcription In reverse transcription, • • • • a retrovirus, which contains viral RNA but no viral DNA, enters a cell the viral RNA uses reverse transcriptase to produce a viral DNA strand the viral DNA strand forms a complementary DNA strand the new DNA uses the nucleotides and enzymes in the host cell to synthesize new virus particles General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc HIV Virus and AIDS The HIV-1 virus • is a retrovirus that infects and destroys T4 lymphocyte cells • leaves the immune system unable to destroy harmful organisms • is associated with an increased chance of developing pneumonia and skin cancer associated with AIDS General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Retroviruses After a retrovirus injects its viral RNA into a cell, it forms a DNA strand by reverse transcription The single-stranded DNA forms a double-stranded DNA called a provirus, which is incorporated into the host cell DNA When the cell replicates, the provirus produces the viral RNA needed to produce more virus particles General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Retroviruses General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc AIDS Treatment Treatment for AIDS is based on • • attacking the HIV at different points in its life cycle developing nucleoside analogs that mimic the structures of the nucleosides used for DNA synthesis Drugs based on nucleoside analogs used to treat HIV/AIDS include • • • • AZT (3ʹ-azido-2ʹ-deoxythymidine), which is similar to thymidine ddI (2ʹ, 3ʹ–dideoxyinosine), which is similar to guanosine ddC (2ʹ,3ʹ-dideoxycytidine) d4T (2ʹ,3ʹ-didehydro-2ʹ,3ʹ-dideoxythymidine) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc AIDS Treatment, Nucleoside Analogs When a nucleoside analog such as AZT, ddI, ddC, or d4T is incorporated into viral DNA, • the lack of a hydroxyl group on the 3ʹcarbon in the sugar prevents the formation of the sugar–phosphate bonds • the production of viral DNA is stopped General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc AIDS Treatment Current treatment for HIV and AIDS involves a combination of drugs that include • • • entry inhibitors reverse transcriptase inhibitors protease inhibitors Lexiva metabolizes slowly to provide amprenavir, an HIV protease inhibitor General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Cancer When cells begin to grow and multiply without control, they invade nearby cells and appear as a tumor Tumors • • that are limited are called benign that invade other tissues, interfering with normal body functions, are cancerous Cancer can be caused by • • • chemical and environmental substances ultraviolet or medical radiation oncogenic viruses Epstein–Barr virus (EBV), herpesvirus 4, causes cancer in humans General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Cancer Most cancers are caused by environmental and chemical substances (carcinogens), including aniline dyes, cigarette smoke, and asbestos General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Cancer Oncogenic viruses cause cancer when cells are infected Some cancers such as retinoblastoma and breast cancer appear to occur within families There is some indication that a missing or defective gene may be responsible General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Study Check Match the following terms to their definitions: 1) virus 2) retrovirus 3) protease inhibitor 4) reverse transcription A a virus containing RNA B small particles requiring host cells to replicate C a substance that prevents the synthesis of viral proteins D using viral RNA to synthesize viral DNA General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Solution Match the following terms to their definitions: 1) virus 2) retrovirus 3) protease inhibitor 4) reverse transcription A a virus containing RNA 2) retrovirus B small particles requiring host cells to replicate C a substance that prevents the synthesis of viral proteins D using viral RNA to synthesize viral DNA 1) virus 3) protease inhibitor 4) reverse transcription General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Concept Map General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc ... nucleotide General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Nucleotides of DNA and RNA General, Organic, and Biological Chemistry: Structures. .. nucleotide General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Phosphodiester Linkage General, Organic, and Biological Chemistry: Structures. .. phosphodiester linkages General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc General, Organic, and Biological Chemistry: Structures of Life,