Copyright © 2010 Pearson Education, Inc. BASIC CHEMISTRY CH. 2
Copyright © 2010 Pearson Education, Inc. Matter and Composition of Matter Definition: Anything that has mass and occupies space Matter is made up of elements –An element c annot be broken down by ordinary chemical means Atoms - are unique building blocks for each element
Copyright © 2010 Pearson Education, Inc. Atomic Structure Neutrons No charge, In atomic nucleus Mass = 1 atomic mass unit (amu) Protons Positive charge,In atomic nucleus Mass = 1 amu
Copyright © 2010 Pearson Education, Inc. Atomic Structure Electrons Negative charge,orbit nucleus Mass = 0 amu Equal in number to protons in atom
Copyright © 2010 Pearson Education, Inc. Figure 2.1 Helium atom Nucleus ProtonNeutronElectron cloud Electron
Copyright © 2010 Pearson Education, Inc. Energy Definition: Capacity to do work or put matter into motion Types of energy: Kinetic: energy associated with motion Potential: stored (inactive) energy Electrical : results from the movement of charged particles (Na+, K+)
Copyright © 2010 Pearson Education, Inc. Identifying Elements Atoms of different elements contain different numbers of protons Compare hydrogen, helium and lithium
Copyright © 2010 Pearson Education, Inc. Figure 2.2 Proton Neutron Electron Helium (He)Lithium (Li)Hydrogen (H)
Copyright © 2010 Pearson Education, Inc. Identifying Elements Atomic number = Mass number = Mass numbers of atoms of an element are not all identical Isotopes = atoms of the same element that differ in the # of neutrons they contain
Copyright © 2010 Pearson Education, Inc. Figure 2.3 Proton Neutron Electron Deuterium ( 2 H)Tritium ( 3 H)Hydrogen ( 1 H)
Copyright © 2010 Pearson Education, Inc. Atoms of Elements can combine Chemically to form Molecules and Compounds Molecule: two or more atoms bonded together (H 2 or C 6 H 12 O 6 )
Copyright © 2010 Pearson Education, Inc. Chemical Bonds Electrons occupy up to seven electron shells (energy levels) around nucleus Octet rule: Except for the first shell which is full with two electrons, atoms interact in order to have eight electrons in their outermost energy level (valence shell)
Copyright © 2010 Pearson Education, Inc. Chemically Inert Elements Stable and unreactive Outermost energy level fully occupied or contains eight electrons
Copyright © 2010 Pearson Education, Inc. Figure 2.4a Helium (He)Neon (Ne) 2e 8e (a) Chemically inert elements Valence shell complete
Copyright © 2010 Pearson Education, Inc. Chemically Reactive Elements Valence shell not fully occupied by electrons Tend to gain, lose, or share electrons (form bonds) with other atoms to achieve stability
Copyright © 2010 Pearson Education, Inc. Figure 2.4b 2e 4e 2e 8e 1e (b) Chemically reactive elements Valence shell incomplete Hydrogen (H)Carbon © 1e Oxygen (O) Sodium (Na) 2e 6e
Copyright © 2010 Pearson Education, Inc. Ionic Bonds Ions are formed by: Anions (– charge) have gained one or more electrons Cations (+ charge) have lost one or more electrons Attraction of opposite charges results in: An ionic bond
Copyright © 2010 Pearson Education, Inc. Figure 2.5 Sodium atom (Na)Chlorine atom (Cl)Sodium ion (Na + )Chloride ion (Cl – ) Sodium chloride (NaCl) +–
Copyright © 2010 Pearson Education, Inc. Covalent Bonds Formed by sharing of two or more valence shell electrons Allows each atom to fill its valence shell at least part of the time
Copyright © 2010 Pearson Education, Inc. Figure 2.7a + Hydrogen atoms Carbon atom Molecule of methane gas (CH 4 ) (a) Formation of four single covalent bonds: or Resulting moleculesReacting atoms
Copyright © 2010 Pearson Education, Inc. Figure 2.7b or Oxygen atom Oxygen atom Molecule of oxygen gas (O 2 ) (b) Formation of a double covalent bond: Resulting moleculesReacting atoms +
Copyright © 2010 Pearson Education, Inc. Figure 2.7c + or Nitrogen atom Nitrogen atom Molecule of nitrogen gas (N 2 ) (c) Formation of a triple covalent bond:. Resulting moleculesReacting atoms
Copyright © 2010 Pearson Education, Inc. Covalent Bonds Sharing of electrons may be equal or unequal Equal sharing produces: Electrically balanced nonpolar molecules
Copyright © 2010 Pearson Education, Inc. Covalent Bonds Unequal sharing by atoms with different electron-attracting abilities produces: polar covalent bonds H 2 O
Copyright © 2010 Pearson Education, Inc. Hydrogen Bonds Attractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule Important in intramolecular bonds, holding a large molecule in a three-dimensional shape
Copyright © 2010 Pearson Education, Inc. (a) The slightly positive ends ( + ) of the water molecules become aligned with the slightly negative ends ( – ) of other water molecules. ++ –– –– –– –– –– ++ ++ ++ ++ ++ Hydrogen bond Figure 2.8
Copyright © 2010 Pearson Education, Inc. Classes of Compounds Inorganic compounds Do not contain carbon (ex. Water, salts, and many acids and bases) Organic compounds Contain carbon, usually large, covalently bonded (ex’s. carbohydrates, fats, proteins, nucleic acids)
Copyright © 2010 Pearson Education, Inc. INORGANIC COMPOUNDS
Copyright © 2010 Pearson Education, Inc. Water 60%–80% of the volume of living cells Most important inorganic compound in living organisms because of its properties
Copyright © 2010 Pearson Education, Inc. Salts Ionic compounds that dissociate into ions in water Ions (electrolytes) conduct electrical currents in solution
Copyright © 2010 Pearson Education, Inc. Acids and Bases Acids Acids : Proton (H+) donors (release H + in solution) HCl H + + Cl – Bases Bases: Proton acceptors (take up H + from solution) NaOH Na + + OH – pH = measure of the acidity/bascisity of a solution
Copyright © 2010 Pearson Education, Inc. Acid-Base Concentration Neutral solutions: pH = 7 Contains equal numbers of H + and OH – Acidic solutions pH = 0–6.99 Contains [H + ], pH Basic solutions pH= 7.01–14 Contains [H + ], pH
Copyright © 2010 Pearson Education, Inc. ORGANIC COMPOUNDS
Copyright © 2010 Pearson Education, Inc. Carbohydrates Sugars and starches whose building blocks = Three classes Monosaccharides -Simple sugars containing three to seven C atoms (glucose) Disaccharides -Double sugars that are too large to pass through cell membranes Polysaccharides - Three/more simple sugars, e.g., starch and glycogen; not very soluble
Copyright © 2010 Pearson Education, Inc. Carbohydrates Functions Primary role: Major source of cellular fuel (glucose)
Copyright © 2010 Pearson Education, Inc. Figure 2.15a Example Hexose sugars (the hexoses shown here are isomers) Example Pentose sugars GlucoseFructose GalactoseDeoxyriboseRibose (a) Monosaccharides Monomers of carbohydrates
Copyright © 2010 Pearson Education, Inc. Figure 2.15b PLAY Animation: Disaccharides Example Sucrose, maltose, and lactose (these disaccharides are isomers) GlucoseFructoseGlucose SucroseMaltoseLactose Galactose (b) Disaccharides Consist of two linked monosaccharides
Copyright © 2010 Pearson Education, Inc. Figure 2.15c PLAY Animation: Polysaccharides Example This polysaccharide is a simplified representation of glycogen, a polysaccharide formed from glucose units. (c) Polysaccharides Long branching chains (polymers) of linked monosaccharides Glycogen
Copyright © 2010 Pearson Education, Inc. Lipids Do not dissolve/mix (Insoluble) in water Main types: Triglycerides Phospholipids Steroids
Copyright © 2010 Pearson Education, Inc. Triglycerides Solid fats and liquid oils Composed of three fatty acids bound to a glycerol molecule Three main functions Energy storage Insulation Protection
Copyright © 2010 Pearson Education, Inc. Figure 2.16a Glycerol + 3 fatty acid chainsTriglyceride, or neutral fat 3 water molecules (a) Triglyceride formation
Copyright © 2010 Pearson Education, Inc. Phospholipids Composed of glycerol + two fatty acids and a phosphorus (P)-containing group The phospholipid “head” is polar and the phospholipid “tail” is nonpolar Phospholipids form cell membranes
Copyright © 2010 Pearson Education, Inc. Figure 2.16b Phosphorus- containing group (polar “head”) Example Phosphatidylcholine Glycerol backbone 2 fatty acid chains (nonpolar “tail”) Polar “head” Nonpolar “tail” (schematic phospholipid) (b) “Typical” structure of a phospholipid molecule Two fatty acid chains and a phosphorus-containing group are attached to the glycerol backbone.
Copyright © 2010 Pearson Education, Inc. Steroids Lipids composed of fused interlocking ring structure Examples are cholesterol, vitamin D, steroid hormones, and bile salts
Copyright © 2010 Pearson Education, Inc. Figure 2.16c Example Cholesterol (cholesterol is the basis for all steroids formed in the body) (c) Simplified structure of a steroid Four interlocking hydrocarbon rings form a steroid.
Copyright © 2010 Pearson Education, Inc. Proteins Building blocks = amino acids Functions of proteins include: acting as enzymes, membrane transport, structure, etc. After amino acids are linked together they often undergo a natural folding process The 3 dimensional shape of a protein is the key to the proteins function (especially enzymes)
Copyright © 2010 Pearson Education, Inc. Protein Denaturation Proteins can undergo changes in shape due to changes in the bodies temperature, pH, or salt concentration A denatured protein is nonfunctional because its’ active sites are not intact
Copyright © 2010 Pearson Education, Inc. Enzymes Are proteins that function as biological catalysts Enzymes increase the speed of a reaction Allows for millions of reactions/minute
Copyright © 2010 Pearson Education, Inc. Substrates Enzyme Active site + Enzyme Function
Copyright © 2010 Pearson Education, Inc. Nucleic Acids DNA and RNA are nucleic acids Building blocks = nucleotides Nucleotides are composed of N-containing base, a (5C) sugar, and a phosphate group
Copyright © 2010 Pearson Education, Inc. Deoxyribonucleic Acid (DNA) Contains four nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T) Double-stranded, helical Replicates before cell division, ensuring genetic continuity Provides instructions for protein synthesis
Copyright © 2010 Pearson Education, Inc. Figure 2.22 Deoxyribose sugar Phosphate Sugar-phosphate backbone Adenine nucleotide Hydrogen bond Thymine nucleotide Phosphate Sugar: Deoxyribose Phosphate SugarThymine (T) Base: Adenine (A) Thymine (T) Cytosine (C) Guanine (G) (b) (a) (c) Computer-generated image of a DNA molecule
Copyright © 2010 Pearson Education, Inc. Ribonucleic Acid (RNA) Four bases: adenine (A), guanine (G), cytosine (C), and uracil (U) Single-stranded PLAY Animation: DNA and RNA
Copyright © 2010 Pearson Education, Inc. Adenosine Triphosphate (ATP) Energy carrying molecule The chemical energy contained in the high energy phosphate bonds can be used to perform cellular work like phosphorylation Phosphorylation is the addition of a phosphate group (PO 4 3- ). This “turns on” the molecule that receives it.
Copyright © 2010 Pearson Education, Inc. Figure 2.19 Adenosine triphosphate (ATP) Adenosine diphosphate (ADP) Adenosine monophosphate (AMP) Adenosine Adenine Ribose Phosphate groups High-energy phosphate bonds can be hydrolyzed to release energy.
Copyright © 2010 Pearson Education, Inc. Figure 2.20 Solute Membrane protein Relaxed smooth muscle cell Contracted smooth muscle cell Transport work Mechanical work Chemical work (a) (b) (c)