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Chemical Level of Organization Chapter 2 Chapter Outline • • • • • Atoms Ions Chemical Bonds pH scale Inorganic molecules o Water, Acids and Salts • Organic molecules o Carbohydrates o Lipids o Proteins o Nucleic Acids – DNA and RNA • ATP – energy carrier of cells Atoms and Ions • • • • • • • All matter is formed of Atoms. Each atom has protons and neutrons in nucleus. Protons are positively charged particles. Neutrons are neutral particles. Nucleus is surrounded by a cloud of electrons. Electrons are negatively charged particles. Ions have different # of protons and electrons. Human Body and Elements • • • • • Human body has 24 elements Elements have only 1 type of atoms. Major Elements – 99.3% H, O, C and N Mineral Elements – 0.7% Trace Elements – less than 0.01% Matter: Atom . Figure 2-1 Matter: Atoms and Molecules . Figure 2-2(b) Importance of # of atomic particles • Atomic Number: is # of protons determine the element; 1 = H, 6 = C, 7 = N and so on. • Mass Number is equal to # of protons + # of neutrons • # of neutrons determine the isotope; C12 is the most common carbon and has 6 p + 6 n but C14 has 6 p + 8 n and is radioactive. • # of electrons in outer shell determines chemical behavior of a atom. Chemical Bonds • Atoms interact to form molecules. 3 basic type of interactions between atoms are: • Covalent bonds • Ionic bonds • Hydrogen bonds Ionic Bonds • Atoms change into ions by complete transfer (loss or gain) of electron/s. • Opposite ions (A positive ion and a negative ion) attract each other and form an ionic bond. • Na+ and Cl- form NaCl = table salt • Strong bonds. Matter: Atoms and Molecules • Ionic Bonding Figure 2-4(a) Matter: Atoms and Molecules • Sodium chloride crystal Figure 2-4(b) Matter: Atoms and Molecules Table 2-2 Figure 2.3a Isotopes = 6p+, 8n0, 6e- Covalent Bonds • Covalent bonds: Atoms share electron pair to form a covalent bond. • Unequal sharing of electrons result in Polar molecules. Equal sharing of electrons result in non-polar molecules. • Very strong bonds. • Non-polar molecule Methane = CH4 • Polar molecules: water = H2O, and ammonia = NH3 • # of covalent bonds made by H = 1, O = 2, N = 3, C = 4 and P = 5 Matter: Atoms and Molecules • Covalent Bonds Figure 2-5 Polar and Non-polar in Solutions • Polar substances dissolve in polar solvents • Non-polar substances dissolve in non-polar solvents • Like dissolves like. • Polar = Hydrophilic (water loving) • Non-polar = Hydrophobic (water fearing) • Amphipathic molecule has both polar and non-polar parts. Bile salts and phospholipids. Hydrogen Bonds • Bonds formed between H of one molecule to O or N of another molecule due to unequal sharing of electron pairs. • Weak bonds • Formed between water molecules Matter: Atoms and Molecules • Hydrogen Bonds Figure 2-6 Recap 1 1. All matter is formed of smallest units --------- to have properties of the substance. 2. # of ---------- determine the chemical substance (element). 3. # of ---------- determine the isotope. 4. Atomic Number is equal to # of ----------- in an atom. 5. Mass Number is sum of # of -------- and # of ----------- in an atom 6. ------------ bonds are formed due to complete transfer of electrons 7. ----------- bonds are formed due to sharing of electrons 8. # of electrons in outer shell determine -------- ---------9. ---------- bonds are very weak bonds formed between different water molecules 2 basic types of Molecules • Inorganic molecules do not form chains and never have Carbon and Hydrogen together, may not have either of them. H2O, CO2, NaCl • Organic molecules always have Carbon and Hydrogen. Most organic molecules also have Oxygen. CH4 = methane, C6H12O6 = Glucose. Organic molecules form long chains but have limited number of functional groups. • –COOH = Carboxylic acid, -NH2= amino, –OH = hydroxyl, and –PO4= phosphate. Inorganic Compounds • Water Dissociates Ionic Bonds Figure 2-8 Acids, Bases and pH scale • • • • • • • • pH is a –ve log measure of H+ Acids release H+ Bases accept H+ or release OHSalts release ions other than H+ or OHpH of water is 7 Strongest acid has 0 pH - HCl Strongest base has 14 pH - NaOH Buffers are chemicals that resist fast changes in pH Inorganic Compounds •pH and Hydrogen Ion Concentration Figure 2-9 Recap 2 1. ----------- is sum of all chemical reactions taking place in body 2. ----------- increase the rate of reactions 3. -------- substances have large molecules with carbon and hydrogen 4. ----------- is stored energy 5. ---------- is energy of moving substances 6. ---------- release H+ 7. pH scale has a range of 0 - ? 8. pH of water is ---9. ------------ resist fast changes to pH of a system. 10. A substance producing ions other than H+ or OH+ is a -----------11. Enzymes act on substances called -----------------12. Reactants need --------------- energy to change to products 13. --------- -------- is the part of enzyme coming in contact with substrate Carbohydrates • Monosaccharide formed of 1 unit – Glucose • Disaccharides formed of 2 units; glucose and fructose form Sucrose – table sugar; other important disaccharides are Maltose – formed of 2 glucose molecules and Lactose formed of glucose and galactose molecules • Polysaccharides are formed of many units. Starch and glycogen are polymers of α-glucose molecules; Cellulose is formed of β-glucose molecules Organic Compounds • Glucose Figure 2-10 Organic Compounds • Formation of Glycogen Figure 2-11(c) Lipids • Fats and fat like substances form lipids • True fats and oils are triglycerides formed from 1 glycerol and 3 fatty acids. • Fats have saturated fatty acids with straight chains and become solids at room temperature. • Oils have unsaturated fatty acids with 1-4 double bonds. Their chain bends at double bond. Oils are liquids at room temperature. • Phospholipids are amphipathic molecules with polar = hydrophobic Head and non-polar = hydrophobic Tails in them. • Steroids have 4 fused ring structure. Cholesterol is building block of steroid hormones. Organic Compounds • Fatty Acids Figure 2-12 Organic Compounds •Triglycerides— Formed by three fatty acid molecules bonding to a glycerol molecule Figure 2-13 Organic Compounds • Cholesterol – Building block for steroid hormones – Component of cell membranes Figure 2-14 Organic Compounds •A Phospholipid Molecule Figure 2-15 Proteins • Proteins are polymers of Amino Acids • Amino acids have an –NH2 and a carboxylic group –COOH • 20 kinds of amino acids form proteins • 2 Amino acids form a covalent bond = peptide bond between them • Polypeptide is a long chain of amino acids joined by peptide bonds Organic Compounds •Proteins are built from amino acids Figure 2-16(a) Organic Compounds •Peptide bonds join amino acids into long strings Figure 2-16(b) Organic Compounds • Protein Structure Figure 2-17 Nucleic Acids DNA and RNA • • • • • • • • • • Nucleic Acid: are acidic substances found in nucleus of cells. 2 basic types: DNA = Deoxyribose N.A. and RNA = ribose N.A. Nucleic acids are polymers of units called Nucleotides. Each nucleotide is formed of: a) a pentose sugar Ribose or Deoxyribose b) a Phosphate c) one of 4 N-bases, both have 3 common bases Adenine, Guanine and Cytosine. In DNA Adenine always bonds to Thymine and Cytosine to Guanine. A-T and C-G are called Complementary bases. DNA RNA Sugar is Deoxyribose Sugar is Ribose N-bases include Thymine N-bases include Uracil Genetic material Executes protein synthesis Double Helix Single chain may be coiled Most lies in nucleus Most lies in cytoplasm 6/19/2007 Organic Compounds •The Structure of Nucleic Acids Figure 2-19ab Organic Compounds •The Structure of Nucleic Acids Figure 2-19cd High-Energy Compounds •Structure of ATP Figure 2-20 ATP Energy from cellular catabolism Energy released for cellular activities ADP Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2-21 1 of 5 Summary of Body Chemistry • Organic Chemical Building Blocks Figure 2-22 Recap 3 1. Most common source of energy from food is the sugar -------------2. Polysaccharide for storage of glucose in body is ---------------3. True fats are formed of 1 glycerol and 3 ------- ----------4. Proteins are polymers of ----------- ---------5. Starch and glycogen are polymers of ---------- ---------6. ----------- bonds join amino acids to form a protein. 7. Nucleic acids are polymers of -------------------8. Genes are formed of ---------9. Cells break down glucose and store energy in the form of ----------10. DNA has ---- chain/s and RNA has ---------- chain/s. 11. In DNA adenine bonds with ---------- and guanine with ---------- base