* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download The Structure and Function of Large Biological Molecules
Expression vector wikipedia , lookup
Signal transduction wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Epitranscriptome wikipedia , lookup
Amino acid synthesis wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Genetic code wikipedia , lookup
Magnesium transporter wikipedia , lookup
Western blot wikipedia , lookup
Gene expression wikipedia , lookup
Interactome wikipedia , lookup
Point mutation wikipedia , lookup
Metalloprotein wikipedia , lookup
Biosynthesis wikipedia , lookup
Two-hybrid screening wikipedia , lookup
Nuclear magnetic resonance spectroscopy of proteins wikipedia , lookup
Protein–protein interaction wikipedia , lookup
LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson Chapter 5 The Structure and Function of Large Biological Molecules Lectures by Erin Barley Kathleen Fitzpatrick © 2011 Pearson Education, Inc. Figure 5.1 Concept 5.1: Macromolecules are polymers, built from monomers • polymer • monomers • Three of the four classes of life’s organic molecules are polymers – Carbohydrates – Proteins – Nucleic acids © 2011 Pearson Education, Inc. The Synthesis and Breakdown of Polymers • dehydration reaction • hydrolysis Animation: Polymers © 2011 Pearson Education, Inc. Figure 5.2a (a) Dehydration reaction: synthesizing a polymer 1 2 3 Unlinked monomer Short polymer Dehydration removes a water molecule, forming a new bond. 1 2 3 Longer polymer 4 Figure 5.2b (b) Hydrolysis: breaking down a polymer 1 2 3 Hydrolysis adds a water molecule, breaking a bond. 1 2 3 4 Concept 5.2: Carbohydrates serve as fuel and building material • Carbohydrates Monosaccharides - or single sugars Polysaccharides - polymers composed of many sugar building blocks © 2011 Pearson Education, Inc. Sugars • Monosaccharides – 1:2:1 ratio CHO classified by – The location of the carbonyl group (as aldose or ketose) – The number of carbons in the carbon skeleton © 2011 Pearson Education, Inc. Figure 5.3 Aldoses (Aldehyde Sugars) Ketoses (Ketone Sugars) Trioses: 3-carbon sugars (C3H6O3) Glyceraldehyde Dihydroxyacetone Pentoses: 5-carbon sugars (C5H10O5) Ribose Ribulose Hexoses: 6-carbon sugars (C6H12O6) Glucose Galactose Fructose Figure 5.3c Aldose (Aldehyde Sugar) Ketose (Ketone Sugar) Hexoses: 6-carbon sugars (C6H12O6) Glucose Galactose Fructose Figure 5.4 1 2 6 6 5 5 3 4 4 5 1 3 6 (a) Linear and ring forms 6 5 4 1 3 2 (b) Abbreviated ring structure 2 4 1 3 2 Figure 5.5 1–4 glycosidic 1 linkage 4 Glucose Glucose Maltose (a) Dehydration reaction in the synthesis of maltose 1–2 glycosidic 1 linkage 2 Glucose Fructose (b) Dehydration reaction in the synthesis of sucrose Sucrose Polysaccharides • Polysaccharides storage structural roles © 2011 Pearson Education, Inc. Storage Polysaccharides • Starch - glucose monomers • stores surplus starch as granules within chloroplasts and other plastids • simplest form of starch is amylose © 2011 Pearson Education, Inc. Figure 5.6 Chloroplast Starch granules Amylopectin Amylose (a) Starch: 1 m a plant polysaccharide Mitochondria Glycogen granules Glycogen (b) Glycogen: 0.5 m an animal polysaccharide Figure 5.6a Chloroplast Starch granules 1 m • Glycogen is a storage polysaccharide in animals • Humans and other vertebrates store glycogen mainly in liver and muscle cells © 2011 Pearson Education, Inc. Figure 5.6b Mitochondria Glycogen granules 0.5 m Structural Polysaccharides • cellulose is a major component of the tough wall of plant cells • polymer of glucose with different glycosidic linkages differ • The difference is based on two ring forms for glucose: alpha () and beta () Animation: Polysaccharides © 2011 Pearson Education, Inc. Figure 5.7 (a) and glucose ring structures 4 1 4 Glucose Glucose 1 4 (b) Starch: 1–4 linkage of glucose monomers 1 1 4 (c) Cellulose: 1–4 linkage of glucose monomers Figure 5.8 Cellulose microfibrils in a plant cell wall Cell wall Microfibril 10 m 0.5 m Cellulose molecules Glucose monomer • Enzymes that digest starch by hydrolyzing linkages can’t hydrolyze linkages in cellulose • Cellulose in human food passes through the digestive tract as insoluble fiber • Some microbes use enzymes to digest cellulose • Many herbivores, from cows to termites, have symbiotic relationships with these microbes © 2011 Pearson Education, Inc. Figure 5.9 The structure of the chitin monomer Chitin forms the exoskeleton of arthropods. Chitin is used to make a strong and flexible surgical thread that decomposes after the wound or incision heals. Concept 5.3: Lipids are a diverse group of hydrophobic molecules • do not form polymers • hydrophobic because they consist mostly of hydrocarbons, which form nonpolar covalent bonds • important lipids are fats, phospholipids, and steroids © 2011 Pearson Education, Inc. Figure 5.10 Fatty acid (in this case, palmitic acid) Glycerol (a) One of three dehydration reactions in the synthesis of a fat Ester linkage (b) Fat molecule (triacylglycerol) Figure 5.11 (a) Saturated fat Structural formula of a saturated fat molecule Space-filling model of stearic acid, a saturated fatty acid (b) Unsaturated fat Structural formula of an unsaturated fat molecule Space-filling model of oleic acid, an unsaturated fatty acid Cis double bond causes bending. • Hydrogenation • trans fats • Energy storage • Omega-3 • Adipose tissue © 2011 Pearson Education, Inc. Hydrophobic tails Hydrophilic head Figure 5.12 Choline Phosphate Glycerol Fatty acids Hydrophilic head Hydrophobic tails (a) Structural formula (b) Space-filling model (c) Phospholipid symbol Hydrophobic tails Hydrophilic head Figure 5.12a (a) Structural formula Choline Phosphate Glycerol Fatty acids (b) Space-filling model Figure 5.13 Hydrophilic head Hydrophobic tail WATER WATER Figure 5.14 Concept 5.4: Proteins • 50% of the dry mass of most cells • functions a. structural support b. Storage c. Transport d. cellular communications e. Movement f. defense against foreign substances © 2011 Pearson Education, Inc. Figure 5.15a Enzymatic proteins Function: Selective acceleration of chemical reactions Example: Digestive enzymes catalyze the hydrolysis of bonds in food molecules. Enzyme Figure 5.15b Storage proteins Function: Storage of amino acids Examples: Casein, the protein of milk, is the major source of amino acids for baby mammals. Plants have storage proteins in their seeds. Ovalbumin is the protein of egg white, used as an amino acid source for the developing embryo. Ovalbumin Amino acids for embryo Figure 5.15c Hormonal proteins Function: Coordination of an organism’s activities Example: Insulin, a hormone secreted by the pancreas, causes other tissues to take up glucose, thus regulating blood sugar concentration High blood sugar Insulin secreted Normal blood sugar Figure 5.15d Contractile and motor proteins Function: Movement Examples: Motor proteins are responsible for the undulations of cilia and flagella. Actin and myosin proteins are responsible for the contraction of muscles. Actin Muscle tissue 100 m Myosin Figure 5.15e Defensive proteins Function: Protection against disease Example: Antibodies inactivate and help destroy viruses and bacteria. Antibodies Virus Bacterium Figure 5.15f Transport proteins Function: Transport of substances Examples: Hemoglobin, the iron-containing protein of vertebrate blood, transports oxygen from the lungs to other parts of the body. Other proteins transport molecules across cell membranes. Transport protein Cell membrane Figure 5.15g Receptor proteins Function: Response of cell to chemical stimuli Example: Receptors built into the membrane of a nerve cell detect signaling molecules released by other nerve cells. Signaling molecules Receptor protein Figure 5.15h Structural proteins Function: Support Examples: Keratin is the protein of hair, horns, feathers, and other skin appendages. Insects and spiders use silk fibers to make their cocoons and webs, respectively. Collagen and elastin proteins provide a fibrous framework in animal connective tissues. Collagen Connective tissue 60 m Amino Acid Monomers • carboxyl and amino groups • differ in their properties due to differing side chains, called R groups © 2011 Pearson Education, Inc. Figure 5.UN01 Side chain (R group) carbon Amino group Carboxyl group Figure 5.16 Nonpolar side chains; hydrophobic Side chain (R group) Glycine (Gly or G) Alanine (Ala or A) Methionine (Met or M) Isoleucine (Ile or I) Leucine (Leu or L) Valine (Val or V) Phenylalanine (Phe or F) Tryptophan (Trp or W) Proline (Pro or P) Polar side chains; hydrophilic Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Electrically charged side chains; hydrophilic Tyrosine (Tyr or Y) Asparagine (Asn or N) Glutamine (Gln or Q) Basic (positively charged) Acidic (negatively charged) Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Arginine (Arg or R) Histidine (His or H) Figure 5.17 Peptide bond New peptide bond forming Side chains Backbone Amino end (N-terminus) Peptide bond Carboxyl end (C-terminus) Figure 5.18 Groove Groove (a) A ribbon model (b) A space-filling model Figure 5.19 Antibody protein Protein from flu virus Four Levels of Protein Structure • primary structure • Secondary structure • Tertiary • Quaternary Animation: Protein Structure Introduction © 2011 Pearson Education, Inc. Figure 5.20a Primary structure Amino acids Amino end Primary structure of transthyretin Carboxyl end Figure 5.20b Tertiary structure Secondary structure Quaternary structure helix Hydrogen bond pleated sheet strand Hydrogen bond Transthyretin polypeptide Transthyretin protein Figure 5.20c Secondary structure helix pleated sheet Hydrogen bond strand, shown as a flat arrow pointing toward the carboxyl end Hydrogen bond Figure 5.20d • Tertiary structure is determined by interactions between R groups • hydrogen bonds • ionic bonds • hydrophobic interactions • van der Waals interactions • disulfide bridges may reinforce the protein’s structure Animation: Tertiary Protein Structure © 2011 Pearson Education, Inc. Figure 5.20f Hydrogen bond Hydrophobic interactions and van der Waals interactions Disulfide bridge Ionic bond Polypeptide backbone Figure 5.20g Quaternary structure Transthyretin protein (four identical polypeptides) Figure 5.20h Collagen Figure 5.20i Heme Iron subunit subunit subunit subunit Hemoglobin Figure 5.20j Sickle-Cell Disease: A Change in Primary Structure • A slight change in primary structure can affect a protein’s structure and ability to function • Sickle-cell disease, an inherited blood disorder, results from a single amino acid(valine) substitution (for glutamic acid) in the protein hemoglobin © 2011 Pearson Education, Inc. Figure 5.21 Sickle-cell hemoglobin Normal hemoglobin Primary Structure 1 2 3 4 5 6 7 Secondary and Tertiary Structures Quaternary Structure Function Molecules do not associate with one another; each carries oxygen. Normal hemoglobin subunit Red Blood Cell Shape 10 m 1 2 3 4 5 6 7 Exposed hydrophobic region Sickle-cell hemoglobin subunit Molecules crystallize into a fiber; capacity to carry oxygen is reduced. 10 m Figure 5.21a 10 m Figure 5.21b 10 m What Determines Protein Structure? • This loss of a protein’s native structure is called denaturation • A denatured protein is biologically inactive © 2011 Pearson Education, Inc. Figure 5.22 tu Normal protein Denatured protein Figure 5.23b Polypeptide Correctly folded protein Steps of Chaperonin 2 The cap attaches, causing 3 The cap comes Action: the cylinder to change off, and the 1 An unfolded polyshape in such a way that properly folded peptide enters the it creates a hydrophilic protein is cylinder from environment for the released. one end. folding of the polypeptide. Techniques to determine protein structure • X-ray crystallography • nuclear magnetic resonance (NMR) spectroscopy • Bioinformatics uses computer programs to predict protein structure from amino acid sequences © 2011 Pearson Education, Inc. Figure 5.24 EXPERIMENT Diffracted X-rays X-ray source X-ray beam Crystal Digital detector X-ray diffraction pattern RESULTS RNA DNA RNA polymerase II Figure 5.25-1 DNA 1 Synthesis of mRNA mRNA NUCLEUS CYTOPLASM Figure 5.25-2 DNA 1 Synthesis of mRNA mRNA NUCLEUS CYTOPLASM mRNA 2 Movement of mRNA into cytoplasm Figure 5.25-3 DNA 1 Synthesis of mRNA mRNA NUCLEUS CYTOPLASM mRNA 2 Movement of mRNA into cytoplasm Ribosome 3 Synthesis of protein Polypeptide Amino acids Figure 5.26 5 end Sugar-phosphate backbone Nitrogenous bases Pyrimidines 5C 3C Nucleoside Nitrogenous base Cytosine (C) Thymine (T, in DNA) Uracil (U, in RNA) Purines 5C 1C 5C 3C Phosphate group 3C Sugar (pentose) Guanine (G) Adenine (A) (b) Nucleotide Sugars 3 end (a) Polynucleotide, or nucleic acid Deoxyribose (in DNA) (c) Nucleoside components Ribose (in RNA) Figure 5.27 5 3 Sugar-phosphate backbones Hydrogen bonds Base pair joined by hydrogen bonding 3 5 (a) DNA Base pair joined by hydrogen bonding (b) Transfer RNA DNA and Proteins as Tape Measures of Evolution • The linear sequences of nucleotides in DNA molecules are passed from parents to offspring • Two closely related species are more similar in DNA than are more distantly related species • Molecular biology can be used to assess evolutionary kinship © 2011 Pearson Education, Inc. The Theme of Emergent Properties in the Chemistry of Life: A Review • Higher levels of organization result in the emergence of new properties • Organization is the key to the chemistry of life © 2011 Pearson Education, Inc. Figure 5.UN02 Figure 5.UN02a Figure 5.UN02b Figure 5. UN03 Figure 5. UN04 Figure 5. UN05 Figure 5. UN06 Figure 5. UN07 Figure 5. UN08 Figure 5. UN09 Figure 5. UN10 Figure 5. UN11 Figure 5. UN12 Figure 5. UN13