90968 - GENERAL AND MOLECULAR BIOCHEMISTRY

Conoscenze e abilità da conseguire

Lo studente al termine del corso conosce e comprende la Biochimica generale (struttura e funzione delle principali molecole biologiche, meccanismi chimici e biochimici alla base della catalisi enzimatica, organizzazione e tappe del metabolismo cellulare) e delle componenti fondamentali della Biologia molecolare (duplicazione del DNA, trascrizione e traduzione); possiede competenze adeguate sia per ideare e sostenere argomentazioni che per risolvere problemi di tipo biochimico; ha la capacità di raccogliere e interpretare i dati (per es. discutere un grafico della velocità di una reazione catalizzata vs. il tempo) ritenuti utili a giudicare un problema biochimico; ha sviluppato quelle capacità di apprendimento che sono loro necessarie per intraprendere studi successivi con un alto grado di autonomia.

Contenuti

Section: Biochemistry - Structures and functions of Biomolecules - Prof.ssa Cappadone (3 ECTS)

The molecules of life: properties of biomolecules. Energy and living systems. Covalent and non covalent bonds. Role of weak bonds in biological molecules. 

Thermodynamics of biological systems: 1st and 2nd laws of thermodynamics, ▲ G and ▲ G° in chemistry and biochemistry, definition of spontaneous reactions. The biological oxidation-reduction reactions. ATP and high energy compounds Coupled reactions. Daily need of ATP in humans.

Amino acids, peptides and proteins: Structure and properties of amino acids. The four levels of structural organization. Peptide bond and primary structure. Secondary structure (alpha-helix, beta sheet, beta turns). Protein structure domains. Tertiary and quaternary structures. Fibrous and globular proteins. Protein denaturation and folding.

Physiological activities of proteins: Structure of myoglobin and haemoglobin. The heme group. Oxygen binding and cooperativity. Competitive inhibitors and allosteric ligands. Hemoglobin variants (embryonic, fetal and pathologic mutant forms).

Enzymes: Classification and general properties of enzymes. Activation energy. Catalytic mechanisms. Cofactors and prosthetic groups.

Kinetics of enzymatic reactions: Analysis of kinetic data and significance of kinetic parameters (Km, Vmax, Kcat). The Michaelis-Menten equation. Effect of pH and temperature on enzymatic activity. Irreversible inhibition. Inhibition of enzymatic activity: competitive and non-competitive reversible inhibition. Drugs as inhibitors. Regulation of enzymatic activity: allosteric enzymes and cooperativity, positive and negative modulators; reversible and irreversible covalent modifications.

Lipids and biomembranes: Fatty acids, triacylglycerols, glycerophospholipids, sphingolipids and steroids. Bilayers. Membrane integral and peripheral proteins. Structural organization and basic functions of biomembranes. Fluidity of membranes. The fluid mosaic model and lipid rafts. Transport across cell membranes, kinetics and thermodynamics of transport. Passive diffusion, uniporter catalyzed transport, active transport by ATP-powered pumps, cotransport by simporters and antiporters.

Section: Biochemistry- Metabolism and its regulation - Prof.ssa Prata (4 ECTS)

Bioenergetics and Metabolism: Anabolic and catabolic pathways.

Cell-to cell signalling, hormones and receptors: Protein G coupled receptors. Signal transduction mechanisms (the cAMP and phosphatidylinositol pathways). Receptor tyrosine kinases. Hormones.

Cellular energetics and glucose catabolism: Oxidation of glucose: the reactions of glycolisis. The anaerobic metabolism of pyruvate: fermentations. Metabolic regulation of glycolisis. The pentose phosphate pathway.

The citric acid cycle (Krebs Cycle): Mitochondrial oxidation of pyruvate and synthesis of acetyl-Coenzyme A. Reactions of the citric acid cycle and its regulation. Reactions related to the citric acid cycle.

Electron transport chain and oxidative phosphorylation: Electron transporters in the mitochondrial respiratory chain. Oxidative phosphorylation and ATP synthesis. Regulation of oxidative phosphorylation Uncoupling and inhibition of the oxidative phosphorilation system .Brown adipose tissue and thermogenesis.

Glycogen metabolism and gluconeogenesis: glycogen breakdown, synthesis and control. Gluconeogenesis: reactions and regulation.

Fatty acids catabolism / oxidation: Lipid digestion, degradation, absorption and transport. Use of fatty acids for energy production: beta-oxidation. Formation and use of ketone bodies. Characteristics, metabolism and functional role of polyunsaturated fatty acids. 

Fatty acid biosynthesis: palmitate synthesis: reactions and regulation. Biosynthesis of polyunsaturated fatty acids: elongation and desaturation. Essential fatty acids. Synthesis of triacilglycerols and glycerophospolipids. Synthesis of cholesterol: early steps. Regulation of fatty acid and cholesterol metabolism.

Amino acid oxidation and urea production:protein degradation. Role of pyridoxal-phosphate in amino acid metabolism. Transamination and oxidative deamination reactions. Nitrogen excretion and urea cycle.

General overview on Regulation of metabolic pathways

Section: Molecular Biochemistry - Prof.ssa Farruggia (3 ECTS)

Purine and pyrimidine bases: structures, tautomeric forms and polarity

Nucleosides and nucleotides: structures and functions

Chemical structures of DNA and RNA: the phosphodiester bond, directionality and polarity of polynucleotide chains

Stability of DNA and RNA: spontaneous hydrolysis, nucleases, restriction endonucleases

Secondary structure of DNA: the Watson-Crick structure: the double helix, complementary base pairing, stability. DNA denaturation. DNA supercoiling. Topoisomerases. Organization of eukaryotic chromatin

Structure of RNA: modified bases. Hairpins and loops. Types of RNA and their functions

The central dogma

DNA replication in prokaryotes : DNA polimerase III in E. coli. The polymerization reaction. OriC. Leading and lagging strand. Roles of DNA polimerase I and ligase. Proof-reading of DNA polimerase I and III. DNA damage and mutations.

RNA transcription in prokaryotes: RNA polymerase in E. coli. The polymerization reaction. Promoters and consensus sequence. Steps of transcription in E. coli. Sigma subunits. Short information about eukaryotic transcription, transcription factors and enhancers. RNA processing. Reverse transcriptase

Regulation of gene expression in prokaryotes:different sigma factors. Operons. Lac operon regulation. Short information about gene expression in eukaryotes

Aminoacyl-tRNA synthethases: reaction, specificity and fidelity

The genetic code: definition, characteristics, codons, reading frame. Type of mutations. Codon-anticodon interactions. The"wobble" pairing. Isoaccepting tRNA. Methionine tRNA.

Protein synthesis in prokaryotes: ribosome structure. The Shine-Dalgarno sequence. Initiation. Chain elongation. Formation of a peptide bond. Chain termination.

Steps in DNA cloning

Testi/Bibliografia

- David L. Nelson and Michael M. Cox. Lehninger Principles of Biochemistry 7th edition

- Textbook of Biochemistry with Clinical Correlations
by Thomas M. Devlin

- Principles of Biochemistry.by Donald Voet, Judith G. Voet, Charlotte W. Pratt

-Biochemistry
by Reginald H. Garrett, Charles M. Grisham

- Biochemistry
by Jeremy M. Berg, John L. Tymoczko, Lubert Stryer

Metodi didattici

Frontal instruction

Modalità di verifica e valutazione dell'apprendimento

The exam at the end of the course aims to assess the achievement of the following objectives:

- To know the structure and function of the main biological macromolecules and the fundamental notions of enzymology.

- To know the cellular bioenergetics, the main metabolic pathways and the mechanisms underlying their regulation and signal transduction.

- Know the basics of molecular biology, the basic molecular mechanisms of living systems, and the molecular logic of their regulation.

The exam consists of a written evaluation. Registration in Alma Esami is required.

The two-hour test consists of 24 multiple-choice questions and 3 open questions. For every correct answer is assigned a score indicated in the test sheet, for the open-questions a maximum score is indicated. No negative score for wrong or unanswered questions is assigned. The test is passed if the score is at least 18.

Strumenti a supporto della didattica

PC and video-projector for Powerpoint and multimedia presentations.

Orario di ricevimento

Consulta il sito web di Cecilia Prata

Consulta il sito web di Concettina Cappadone

Consulta il sito web di Giovanna Farruggia