Có 20+ tài liệu thuộc chủ đề "công nghệ DNA"
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in pyrimidine synthesis, 828 structure of, 10S. synthesis of, 118F, 119 Polypeptide chain, 89. fragmentation of F, 105T separation of, 101. description of, 213 function of, 194–195 naming of, 194 storage, 194 structural, 196–201 structure of, 10S Polysome. See also Amino acid sequencing. regulation of F, 915F, 916T, 917B, 917T, 918F, 918G, 919F, 921F, 922F. structure of, 72S, 150S synthesis...
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Temperature Dependence of the Equilibrium Constant H ° Rd(ln K eq )/d(1/T). If the access code card was not ordered with your text, or you have a used version of the text, you can purchase access to this remarkable program for a nominal fee. www.cengage.com/tlc. Carboxyl group COO – In reactions, blocks of color over parts of molecular structures are...
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3.1 What Are the Basic Concepts of Thermodynamics? 48 The First Law: The Total Energy of an Isolated System Is Conserved 48. A DEEPER LOOK: Entropy, Information, and the Importance of “Negentropy” 52. 3.5 What Are the Characteristics of High-Energy Biomolecules? 56. Enol Phosphates Are Potent Phosphorylating Agents 63 3.6 What Are the Complex Equilibria Involved in ATP. A DEEPER...
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20.8 How Do Mitochondria Mediate Apoptosis? 624 Cytochrome c Triggers Apoptosome Assembly 625 SUMMARY 626. 21.2 How Is Solar Energy Captured by Chlorophyll? 633 Chlorophylls and Accessory Light-Harvesting Pigments Absorb Light of Different Wavelengths 634. 21.6 How Does Light Drive the Synthesis of ATP? 648 The Mechanism of Photophosphorylation Is Chemiosmotic 648. 21.7 How Is Carbon Dioxide Used to Make...
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Scientific understanding of the molecular nature of life is growing at an astounding rate. Cures for diseases, better public health, remedies for environmental pollution, and the development of cheaper and safer natural products are just a few practical ben- efits of this knowledge.. In addition, this expansion of information fuels, in the words of Thomas Jeffer- son, “the illimitable freedom...
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FIGURE 1.4 Organisms resemble their parents. (b) Orangutan with infant.(c) The Grisham family. of self-replication resides ultimately in the chemical nature of the genetic material.. These mole- cules can generate new copies of themselves in a rigorously executed polymeriza- tion process that ensures a faithful reproduction of the original DNA strands. In contrast, the molecules of the inanimate world lack...
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Ionic Interactions Ionic interactions are the result of attractive forces between op- positely charged structures, such as negative carboxyl groups and positive amino groups (Figure 1.15). The strength of electrostatic interactions is highly dependent on the nature of the interacting species and the distance, r, between them. Thus, nonpolar re- gions of biological macromolecules are often buried in the molecule’s...
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A distinct RNA-rich region, the nucleolus, is the site of ribosome assembly.. Flattened sacs, tubes, and sheets of internal membrane extending throughout the cytoplasm of the cell and en- closing a large interconnecting series of volumes called cisternae. The ER membrane is continuous with the outer membrane of the nuclear envelope. Portions of the sheet- like areas of the ER...
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Their behavior in aqueous solution reflects the com- bination of the contrasting polar and nonpolar nature of these substances. Figure 2.7b depicts their structure.. Colligative Properties This influence of the solute on water is reflected in a set of characteristic changes in behavior termed colligative properties, or properties re- lated by a common principle. These alterations in solvent properties are...
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The important buffer system of blood plasma is the bicarbonate/. (The pK 1 for H 2 CO 3 at 25°C is 3.77 [Table 2.4], but at 37°C, pK 1 is 3.57.) At pH 7.4, the concentration of H 2 CO 3 is a minuscule fraction of the HCO 3 concentration. pH 7.4 3.57 log 10. For example, if [HCO 3...
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Free Energy Provides a Simple Criterion for Equilibrium. Willard Gibbs, one of the founders of thermodynamics, realized that the answer to this question lay in a comparison of the enthalpy change and the entropy change for a reaction at a given temperature.. For any process A34 B at constant pressure and temperature, the free energy change is given by. Any...
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The value of G ° de- pends on the pK a values of the starting anhydride and the product phosphoric and carboxylic acids, and of course also on the pH of the medium.. The very large negative value of G° for the latter reaction is to a large extent the result of a secondary reaction of the enol form of...
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COOH C H CH 2 CH 2. CH 2 CH 2. FIGURE 4.3 continued. 74 Chapter 4 Amino Acids. Nonpolar Amino Acids The nonpolar amino acids (Figure 4.3a) are critically im- portant for the processes that drive protein chains to “fold,” that is to form their nat- ural (and functional) structures, as shown in Chapter 6. Amino acids termed nonpolar...
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Amino Acids Can Be Characterized by Nuclear Magnetic Resonance. The development in the 1950s of nuclear magnetic resonance (NMR), a spectro- scopic technique that involves the absorption of radio frequency energy by certain nuclei in the presence of a magnetic field, played an important part in the chemical characterization of amino acids and proteins. FIGURE 4.10 The ultraviolet absorption spectra...
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Proteins are a diverse and abundant class of biomolecules, constituting more than 50% of the dry weight of cells. An extraordi- nary diversity of cellular activity is possible only because of the versatility inherent in proteins, each of which is specifically tailored to its biological role. Each such segment of encoded information defines a gene, and expression of the gene...
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in the protein. a typical 2000–amino acid protein provides only 10 to 20 cycles of reaction.. C-Terminal Analysis For the identification of the C-terminal residue of polypep- tides, an enzymatic approach is commonly used. Carboxypeptidases are enzymes that cleave amino acid residues from the C-termini of polypeptides in a successive fashion.. Because the nature of the amino acid residue at...
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The number of amino acid differences between two cytochrome c sequences is propor- tional to the phylogenetic difference between the species from which they are de- rived. The Phylogenetic Tree for Cytochrome c Figure 5.20 displays a phylogenetic tree (a diagram illustrating the evolutionary relationships among a group of organisms) constructed from the sequences of cytochrome c. The tips of...
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mentary to the structure of the ligand, its charge distribution, and any H-bond donors or acceptors it might have. Structural complementarity within the binding site is achieved because part of the three-dimensional structure of the protein pro- vides an ensemble of amino acid side chains (and polypeptide backbone atoms) that establish an interactive cavity complementary to the ligand molecule. When...
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where p is the density of the particle or macromolecule, m is the density of the medium or solution, V is the volume of the particle, and f is the frictional coeffi- cient, given by. where v is the velocity of the particle and F f is the frictional drag. Essentially all of the information required to initiate, conduct, and...
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A -pleated sheet can be visualized by laying thin, pleated strips of paper side by side to make a “pleated sheet” of paper (Figure 6.10). Each strip of paper can then be pictured as a single peptide strand in which the peptide backbone makes a zigzag pattern along the strip, with the -carbons lying at the folds of the pleats....