lehninger principles of biochemistry, fourth edition - david l. nelson, michael m. cox

[...]... presentation and analysis of the long-awaited structure of the ribosome-one of the most important updates in this new edition Adds a new box on the evolutionary significance of ribozyme-catalyzed peptide synthesis 28 Regulation of Gene Expression 28.1 Principles of Gene Regulation 28.2 Regulation of Gene Expression in Prokaryotes 28.3 Regulation of Gene Expression in Eukaryotes Adds a new section on... character beyond that of its individual parts The collection of molecules carries out a program, the end result of which is reproduction of the program and self-perpetuation of that collection of molecules—in short, life A history of evolutionary change Organisms change their inherited life strategies to survive in new circumstances The result of eons of evolution is an enormous diversity of life forms, superficially... a single biomolecule Acetyl-coenzyme A (often abbreviated as acetyl-CoA) is a carrier of acetyl groups in some enzymatic reactions Acetyl-coenzyme A of the cell or between compartments in eukaryotic cells The universal occurrence of the same set of compounds in living cells is a manifestation of the universality of metabolic design, reflecting the evolutionary conservation of metabolic pathways that... requires the input of much energy (b) In the vertebrate retina, the initial event in light detection is the absorption of visible light by 11-cis-retinal The energy of the absorbed light (about 250 kJ/mol) converts 11-cis-retinal to all-trans-retinal, triggering electrical changes in the retinal cell that lead to a nerve impulse (Note that the hydrogen atoms are omitted from the ball-andstick models... CH3 C J G O H All-trans-Retinal 11-cis-Retinal (b) filling models, the radius of each atom is proportional to its van der Waals radius, and the contours of the model define the space occupied by the molecule (the volume of space from which atoms of other molecules are excluded) Configuration is conferred by the presence of either (1) double bonds, around which there is no freedom of rotation, or (2)... fraction of the weight of the human body, but all are essential to life, usually because they are essential to the function of specific proteins, including enzymes The oxygen-transporting capacity of the hemoglobin molecule, for example, is absolutely dependent on four iron ions that make up only 0.3% of its mass Biomolecules Are Compounds of Carbon with a Variety of Functional Groups The chemistry of living... bases HOCH2 O HO H ␣ -D-Ribose 2-Deoxy-␣-D-ribose Five-carbon sugars Glycerol CH2 CH2 CH2 CH2 CH CH2 CH CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 O CH2OH CH2 CH2 Cytosine CH2 CH2 N H O CHOH CH2 CH CH2 CH2 CH C CH O CH2 CH2 N CH2OH CH2 C HN NH2 COOϪ CH2 O COOϪ CH2 O CH2 CH2 CH2 CH3 N CH2CH2OH CH3 Choline (d) The parent sugar H CH3 Palmitate CH3 ϩ CH3 Oleate CH 2OH O H OH H H OH HO H OH ␣ -D-Glucose 8885d_c01_011... RNA-Dependent Synthesis of RNA and DNA Updates coverage on mechanisms of mRNA processing Adds a subsection on the 5' cap of eukaryotic mRNAs Adds important new information about the structure of bacterial RNA polymerase and its mechanism of action 27 Protein Metabolism 27.1 The Genetic Code 27.2 Protein Synthesis 27.3 Protein Targeting and Degradation Includes a presentation and analysis of the long-awaited... carbon-12 Since the experimentally measured mass of an atom of carbon-12 is 1.9926 ϫ 10Ϫ23 g, 1 u ϭ 1.6606 ϫ 10Ϫ24 g The atomic mass unit is convenient for describing the mass of a peak observed by mass spectrometry (see Box 3–2) 8885d_c01_016 16 11/3/03 Chapter 1 1:40 PM Page 16 mac76 mac76:385_reb: The Foundations of Biochemistry TABLE 1–2 Molecular Components of an E coli Cell Percentage of total... O FIGURE 1–11 Structural hierarchy in the molecular organization of cells In this plant cell, the nucleus is an organelle containing several types of supramolecular complexes, including chromosomes Chro- mosomes consist of macromolecules of DNA and many different proteins Each type of macromolecule is made up of simple subunits— DNA of nucleotides (deoxyribonucleotides), for example with the light . and Hormonal Regulation of Mammalian Metabolism 23.1 Tissue-Specific Metabolism: The Division of Labor 23.2 Hormonal Regulation of Fuel Metabolism 23.3 Long Term Regulation of Body Mass . recycles macromolecules, stores metabolites (a) Animal cell (b) Plant cell Glyoxysome contains enzymes of the glyoxylate cycle FIGURE 1–7 Eukaryotic cell structure. Schematic illustrations of the two. h) Differential centrifugation Tissue homogenization Tissue homogenate Pellet contains mitochondria, lysosomes, peroxisomes Pellet contains microsomes (fragments of ER), small vesicles Pellet contains ribosomes, large macromolecules Pellet contains whole cells, nuclei, cytoskeletons, plasma membranes Supernatant contains soluble proteins ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ▲ ❚❚ ❚❚ ❚❚ (a) ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ❚❚ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚ FIGURE