CHEMISTRY OF LIFE BOT.pdf

Chemistry of Life  Element Atom – Smallest unit of an element – Protons Positively charged – Neutrons Neutral, no charge – Electrons Negatively charged Element  Matter Matter – Anything that takes up space and has mass Elemen...

Chemistry of Life  Element Atom – Smallest unit of an element – Protons Positively charged – Neutrons Neutral, no charge – Electrons Negatively charged Element  Matter Matter – Anything that takes up space and has mass Element – Substance that cannot be broken down to other substances by chemical reactions Gold, copper, lead, carbon, oxygen  Matter Compound – Consists of two or more elements combined in a fixed ratio – Water (H2O), table salt (NaCl), Ammonia NH3) Essential Elements – Macromolecules C, O, H, N – Micromolecules Fe, I, Mg  Chemical Bonding Interactions between valence electrons of different atoms – Forming molecules A. Covalent bonds – Electron sharing  Chemical Bonding Electronegativity Covalent Bonds A.1 Non-polar covalent bonds Equal sharing of electrons  Chemical Bonding A.2 Polar covalent bonding – Unequal sharing of electrons  Chemical Bonding B. Ionic Bond – Electron transfer Resulting to ions – Cations » Positive ions – Anions » Negative ions  Chemical Bonding A. Hydrogen Bonds – Relatively weak bonds Form between the positively charged hydrogen; and Strongly electronegative oxygen or nitrogen  Chemical Bonding Van del Waals interactions – Very weak transient connections Result of asymmetrical distribution of electrons within a molecule Contribute to the three dimensional shape of large molecules  Water and the Fitness of the Environment A. Water structure is the key to its special properties B. Polar  Water and the Fitness of the Environment Hydrogen bonds – Unique property of water  Water Emergent Properties 1. Cohesion/Adhesion a) Cohesion Bonding of “like” molecules b) Adhesion Clinging of one substance to another c) Transpiration Upward movement of water molecules on the xylem tubes Evaporation from the stomates in plants Water and the Fitness of the Environment 2. Surface tension – Is a measure of how hard it is to break the surface of a liquid Is related to cohesion 3. Moderation of Temperature Water moderates air temperature By absorbing heat from air that is warmer and releasing the stored heat to air that is cooler 4. High Specific Heat – Specific heat Amount of heat required to raise or lower the temperature of 1g of a substance by 1 degree Celsius Water has a high specific heat which allows it to minimize temperature fluctuations to within limits that permit life – Heat is absorbed when hydrogen bonds break – Heat is released when hydrogen bonds form 5. Evaporative Cooling Is due to water’s high heat of vaporization Allows water to cool a surface Sweating cools the body as heat energy from the body changes sweat into a gas Insulation of bodies of water – Liquid water is denser than solid ice Keeps large bodies of water from freezing Thermoregulation  Water and the Fitness of the Environment 6. Universally accepted Solvent – Solute Substance being dissolved – Solvent Substance that dissolves solutes – Solution Hydrophillic – water soluble Hydrophobic – does not dissolve in water Acids and Bases  Macromolecules Monomers – Building blocks of polymers Polymers – Long chains of molecules made of repeating subunits called monomers Carbohydrates Lipids Proteins Nucleic Acids  Macromolecules How are polymers formed? Condensation or dehydration reactions – Two monomers are joined by removing one molecule of water – C6H12O6 + C6H12O6→ C12H22O11 + H2O  Macromolecules Hydrolysis – Water molecule is added to split large molecules Reverse of condensation reaction  Carbohydrates CHO Monosaccharides – Monomers of carbohydrates – Covalent bonds – E.g. glucose, fructose, galactose  Carbohydrates Disaccharides – Polymers made of two monomers put together – Sucrose, maltose, lactose  Carbohydrates Polysaccharides – Long chain polymers of monosaccharides – Starch, cellulose, and glycogen  Carbohydrates What are the functions of Carbohydrates? 1. Energy Storage – Starch Found In plants e.g potato – Amylose and amylopectin – Glycogen Animals e.g liver, muscle  Carbohydrates 2. Structural Support – Cellulose Plant cell wall – Chitin Exoskeleton of arthropods  Lipids CHO Hydrophobic – non-polar They do not form polymers – Triglycerides – Glycerol molecule 3 long fatty acid molecules – Ester bonds  Lipids What are the two kinds of Fatty acids? – Saturated fatty acids No double bonds Solid at room temperature Commonly produced by animals  Lipids Unsaturated Fatty Acids – C=C; kinks or bending – Liquid at room temperature – Commonly produced by plants  Lipids What are the types of Lipids? Phospholipids – Make up the cell membrane – Glycerol backbone head – 2 fatty acid chains tail  Lipids What are the functions of lipids? 1. Energy storage – Fats store twice as many calories/gram as carbohydrates 2. Protection – Of vital organs and insulation – Stored in adipose tissues  Lipids Steroid – Cholesterol Common component of cell membranes – Estrogen and testosterone Steroid hormones  Proteins CHONS Made up of amino acids – Amino acids contain: Central carbon atom bonded to a carboxyl group, an amino group, an R group, and a hydrogen atom  Proteins Peptide bonds formed by dehydration synthesis Function depends on the order and number of amino acids R group determines the characteristic of each amino acid Examples – Hemoglobin, albumin, enzymes  Proteins Peptide bonds What are the Different Amino Acids? What are the Different Amino Acids? Proteins  Proteins Protein shape is crucial to protein function Why? When a protein does not fold properly, its function is changed. Chaperonins – Protein molecules that allow proper folding of polypeptides  Proteins Chaperonins  Proteins What are the causes of change in protein shape/function? A. Amino acid substitution B. Denaturation – Heat, change in pH  Proteins What are the functions of protein? 1. Control of Biological System – Enzymes 2. Structural Support – Cell membrane, muscle tissues,  Proteins Enzymes  Proteins Enzymes  Proteins What are the properties of enzymes? 1. Reaction specific – Substrate specific – Lock and key model – e.g. sucrase, protease, lipase, DNA polymerase 2. Reusable – Not consumed in the reaction – Single enzyme molecule can catalyze thousands or more reactions per second  Factors Affecting Enzymes Enzyme concentration Substrate concentration Temperature pH Salinity Activators Inhibitors  Nucleic Acids CHONSP Nucleotide monomers DNA and RNA are the two nucleic acids 1. Nitrogenous base – Pyrimidines cytosine, uracil, thymine – Purines adenine, guanine  Nucleic Acids 2. Pentose sugar 3. Phosphate group  Nucleic Acids Phosphodiester bond – Bond formed between the sugar and the phosphate group  Nucleic Acids RNA – Single stranded – A=U – C=G DNA – Molecule of heredity Double stranded helix – Nitrogenous bases – A=T – C=G  Nucleic Acids DNA – double helix 1st proposed as structure of DNA in 1953 by James Watson & Francis Crick  Nucleic Acids Rosalind Franklin (1920-1958) First to observe DNA using x-ray Nucleic Acids  Nucleic Acids A-T to G-C ratio affects the stability of DNA molecule G-C with three H bonds is stronger that A-T with only two H bonds  Nucleic Acids What is the function? – Series of bases encodes information – Stored information is passed from parent to offspring  Nucleic Acids DNA Replication – Process of producing two new daughter strands from a molecule of DNA Summary