Big Campbell ~ Ch 2-5 Baby Campbell ~ Ch 2-3 UNIT II - BIOCHEMISTRY Big Campbell ~ Ch 2-5 Baby Campbell ~ Ch 2-3

I. CHEMICAL BASIS OF LIFE Elements Cannot be broken down without losing characteristic properties Six elements in greatest concentration in living things are Defined by

I. CHEMICAL BASIS OF LIFE, cont Atoms Smallest unit of matter that retains properties of that element Atomic Mass Isotopes

I. CHEMICAL BASIS OF LIFE, cont Chemical Bonds Chemical behavior of atom determined by valence electrons Atoms interact with other atoms to complete their valence shells, either by transferring or sharing electrons

I. CHEMICAL BASIS OF LIFE, cont Types of Chemical Bonds Ionic – Results when one atom has a much stronger attraction for electrons than another; one atom has a greater electronegativity. Electron(s) are transferred resulting in formation of ions. Bond forms due to charge attraction. Strength is dependent on environment

I. CHEMICAL BASIS OF LIFE, cont Covalent Bonds – More stable; results from sharing a pair of valence electrons. Forms a molecule. One pair of electrons shared = single covalent bond; two pair of electrons shared = double covalent bond. Non-polar covalent bond – formed when electronegativity of atoms is the same Polar covalent bond – formed when one atom is more electronegative; unequal sharing of electrons results in slight charges at either end of molecule

II. WATER Properties of Water Due to its Polarity Hydrogen “bonds” “Stickiness” Cohesion Surface Tension Adhesion Capillary Action

II. WATER, cont Regulation of Temperature High specific heat High heat of vaporization Density of “solid” water ____ density of liquid water Solvent of Life “Water-loving” Polar molecules “pull apart” ionic compounds & other polar molecules “Water-hating” Non-ionic and non-polar substances are repelled by water

II. WATER, cont Dissociation of Water Rare, but measurable phenomenon (2)H2O → H3O+ + OH- → H+ + OH- In aqueous solution at 25˚C, total conc of [H+] [OH-] = 1x10-14 Neutral solution → [H+] = [OH-]; therefore [H+] = pH = Provides a means for a compressed measurement of [H+] -log10[H+] Acid – Substance that dissolves in water to ____________ [H+] [H+] ____ 1 x 10-7; pH ____ 7 Base - Substance that dissolves in water to ____________ [H+] pH of Water =

II. WATER, cont Buffers Maintain a constant pH by donating, accepting H+ Bicarbonate Buffer System Very important buffer system in blood pH of blood = _________

III. ORGANIC CHEMISTRY – THE STUDY OF CARBON Atomic Structure of C Atomic Number of C = _____ valence electrons Hydrocarbon Isomer

III. ORGANIC CHEMISTRY, cont Functional Group Structure Characteristics Hydroxyl Very polar; forms “ –ols” Carbonyl Carboxyl Acts as an acid; donates H+ to solution Amino Acts as a base; removes H+ from solution

III. ORGANIC CHEMISTRY, cont Functional Group Structure Characteristics Sulfhydryl Important in stabilizing protein structure; forms disulfide bridges Phosphate Gives molecule negative charge; react with water to release energy Methyl Affects the expression of DNA

IV. THE BIOMOLECULES Most are polymers made up of single units called monomers Four Main Groups

IV. BIOMOLECULES, cont Dehydration Synthesis Also called ________________________ Reaction that occurs to build polymers Forms ________________ bond between 2 monomers ____________lost as waste product Requires energy input, enzymes

IV. BIOMOLECULES, cont Hydrolysis “________________________” Covalent bonds between monomers broken Releases energy; reaction accelerated with enzymes

V. CARBOHYDRATES Provide fuel, act as building material Generally, formula is a multiple of CH2O Contain carbonyl group & multiple hydroxyl groups Monomer = monosaccharides Monosaccharides – usually found as ringed structures Pentoses Ribose Deoxyribose

V. CARBOHYDRATES, cont Hexoses Glucose Fructose Galactose

V. CARBOHYDRATES, cont Disaccharides 2 monosaccharides covalently bonded together through dehydration synthesis Example Sucrose Lactose Maltose

V. CARBOHYDRATES, cont Polysaccharides Many monosaccharides covalently bonded together through dehydration synthesis Two main groups Energy Storage Polysaccharides Starch – Plants store glucose as starch in cell structures called plastids. Humans have enzymes to hydrolyze starch to glucose monomers. Glycogen – Storage form of glucose in animals. More highly-branched than starch. In humans, found mainly in liver, muscle cells

V. CARBOHYDRATES, cont Structural polysaccharides Cellulose – polymer of glucose. Every other glucose is upside down – forms parallel strands of glucose molecules held together with H-bonds Chitin – found in arthropod exoskeleton, cell walls of fungi

VI. LIPIDS Very diverse group Non-polar, hydrophobic molecules Not true polymers Four groups

VI. LIPIDS, cont Fats& Oils Composed of glycerol + 3 fatty acids Glycerol = 3-C alcohol Fatty acids – long hydrocarbon chains ending with carboxyl group AKA triglycerides Used for energy storage

VI. LIPIDS, cont Saturated fats – “Saturated with hydrogens”; contain all single bonds. Typically from animal source, solid at room temp. Associated with greater health risk. Unsaturated fats – Contain double bonds, fewer H-atoms. Results in “kinked” hydrocarbon chain. Typically from plant source, liquid at room temp.

VI. LIPIDS, cont Phospholipids 2 fatty acids attached first 2-carboxyl groups of glycerol. Negatively-charged phosphate group is attached to 3rd carboxyl Partially polar and partially non-polar Found in all cell membranes.

VI. LIPIDS, cont Waxes – One fatty acid attached to an alcohol. Very hydrophobic. Used as coating, lubricant Steroids – Consist of 4-rings with different functional groups attached. Cholesterol – steroid found in animal cell membranes; precursor for sex hormones

VII. PROTEINS Important part of virtually all cell structures, processes, reactions Amino Acids – Proteins are large polymers made up of amino acid monomers. All amino acids have the same basic structure: Amino group Carboxyl group Carbon, known as alpha carbon R group → variable component; gives each amino acid its unique properties. Determines whether amino acid is classified as polar, non-polar, acidic, or basic.

VII. PROTEINS, cont

VII. PROTEINS, cont

VII. PROTEINS, cont

VII. PROTEINS, cont Amino Acid → Protein Dehydration synthesis results in formation of a peptide bond Polypeptide – many amino acids covalently bonded together

VII. PROTEINS, cont Protein Conformation Protein’s shape is related to its function. Generally, a protein must recognize/bind to another molecule to carry out its function. Denaturation - A change in a protein’s shape. Results in a loss of protein’s ability to carry out function. Four levels of protein structure Primary Secondary Tertiary Quaternary

VII. PROTEINS, cont Primary – Sequence of amino acids

VII. PROTEINS, cont Secondary – Coiling of polypeptide chain due to formation of H-bonds between H of amino end of one aa and OH of carboxyl end of another aa Alpha helix – created from H-bonds forming within one pp chain Beta pleated sheet – H-bonds form between aa in parallel pp chains

VII. PROTEINS, cont Tertiary - Involves interactions between R groups of amino acids. Helps to give each protein its unique shape.

VII. PROTEINS, cont Quaternary – Proteins that are formed from interactions between 2 or more polypeptide chains folded together. Examples include hemoglobin, collagen, chlorophyll

VII. PROTEINS, cont Enzymes Biological catalysts that act by lowering activation energy; that is, the amount of energy needed to get the reaction going Only catalyze reactions that would normally occur Recycled – not used up or changed by the reaction Temperature and pH sensitive Substrate specific

VII. PROTEINS, cont Induced fit – As enzyme envelops substrate, a slight change takes place in bond angles, orientation of atoms. Allows chemical rxns to occur more readily Inhibition of Enzyme Function Competitive inhibitor – mimics normal substrate Non-competitive inhibitor – attaches to another part of enzyme; changes shape of active site

VII. PROTEINS, cont Regulation of enzyme function Allosteric Regulation – binding of a molecule to enzyme that affects function of protein at another site Feedback Inhibition – as end product is synthesized and accumulates, enzyme is inactivated → switches off metabolic pathway

VIII. NUCLEIC ACIDS Nucleic acid group includes DNA, RNA, ATP Monomers = __________________ Composed of Pentose Phosphate group Nitrogen base Polymers formed through ____________________________ Phosphate group of one nucleotide covalently binds to sugar of next

VIII. NUCLEIC ACIDS, cont Nitrogen Bases Pyrimidines – Single-ringed structure Purines – Double-ringed structure

VIII. NUCLEIC ACIDS, cont DNA