Functional Groups Aldehydes, Ketones, Carboxylic acids, Esters and Phenols

Transcription

1 Functional Groups Aldehydes, Ketones, Carboxylic acids, Esters and Phenols BIOB111 CHEMISTRY & BIOCHEMISTRY Session 9

2 Key concepts: session 9 From this session you are expected to develop an understanding of the following concepts: Concept 1: Carboxylic acids behave like an acid Concept 2: Ketones resist oxidation Concept 3: Alcohol breakdown Concept 4: Alcohol breakdown reactions Concept 5: Alcohol breakdown in individuals of Asian decent Concept 6: Esters within triacylglycerol (TAG) Concept 7: Esters hydrolysis Concept 8: Phenol groups are present in antioxidants Concept 9: Consequence of too few antioxidants These concepts are covered in the Conceptual multiple choice questions of tutorial 9

3 Session Overview Part 1: Exploring carbonyl containing functional groups Hydrocarbon derivatives The carbonyl group Chemical properties of ketones Chemical properties of aldehydes Chemical properties of carboxylic acids Part 2: Redox reactions involving functional groups Redox reactions Breakdown of alcohol in the liver Part 3: Exploring the ester and phenol functional groups Chemical properties of esters TAG contains ester connections Chemical properties of phenols Free radicals

4 Part 1: Exploring carbonyl containing functional groups Hydrocarbon derivatives The carbonyl group Chemical properties of ketones Chemical properties of aldehydes Chemical properties of carboxylic acids

5 Hydrocarbon derivatives Life on earth would not exist without organic compounds that contain carbon atoms Our genetic material (DNA) contains many carbon atoms Our bodies rely on the organic compounds below to function: Proteins are made up of amino acids Lipids are often made up of fatty acids (long hydrocarbons) and glycerol Carbohydrates are made up of one or more monosaccharide (sugar) units

6 Hydrocarbon derivatives Hydrocarbon derivatives are: Hydrocarbon compounds that contain atoms such as oxygen, nitrogen, fluorine or chlorine as well as carbon and hydrogen atoms The location within the hydrocarbon derivative that has atoms other than just carbon and hydrogen is where the functional group is located Ethanol: present in alcoholic beverages Alcohol

7 Hydrocarbon derivatives What are functional groups? A functional group is a group of atoms within a compound that provides chemical reactivity The functional group is usually the part of the compound that is involved in chemical reactions All compounds with a particular functional group will behave similarly in chemical reactions To find a functional group within a compound, look for atoms other than just carbon and hydrogen atoms Ethanol: present in alcoholic beverages Alcohol

8 The carbonyl group Carbonyl group: A carbonyl group is made up of a carbon atom that forms a double bond to an oxygen atom The carbon atom within the carbonyl group must form chemical bonds to two other atoms or groups of atoms to be stable Carbon atoms form 4 covalent bonds to gain 8 valence electrons A carbonyl group is not a functional group The carbonyl group is present in many functional groups Carbonyl Group

9 The carbonyl group The carbonyl group is present in many functional groups: Aldehyde Ketone Carboxylic Acid Ester Amide Carbonyl Group Aldehyde Ketone Carboxylic acid Ester Amide

10 Chemical properties of ketones Functional Group: Ketone Functional group formula: R CO R The ketone functional group is a carbonyl attached to two R-groups Naming convention: Ketone compounds have one at the end of their name e.g. propanone Example compound: Propanone The ketone functional group is located in the middle of compounds, as it contains two R-groups

11 Chemical properties of ketones PROPANONE: Commonly known as acetone Acetone is found in paint and nail polish removers Acetone is a ketone body which is created when acetoacetate (produced via ketogenesis) breaks down Propanone The sweet odor of acetone can be detected on the person s breath who is in a state of ketosis

12 Chemical properties of ketones Steroid Hormones Steroid hormones such as testosterone, progesterone and cortisone (can be converted to cortisol) contain the ketone functional group Stoker 2014, p476

13 Chemical properties of aldehyde Functional Group: Aldehyde Functional group formula: R CHO The aldehyde function group is a carbonyl attached to a hydrogen Naming convention: Aldehyde compounds have al at the end of their name e.g. propanal Example compound: Propanal The aldehyde functional group is located at the end of a compound (or a branch point), as it contains one R-group

14 Chemical properties of aldehyde Methanal Methanal is commonly known as formaldehyde Dissolved in solution to preserve biological specimens e.g. cadavas Methanal aka formaldehyde Formaldhyde is a carcinogen and teratogen (causes birth defects) Present in tobacco smoke Exposure triggers burning, nausea, difficulty breathing and asthma attacks Many other aldehyde compounds exist that contain more carbon atoms Ethanal (2 carbon atoms) Propanal (3 carbon atoms)

15 Chemical properties of carboxylic acid Functional Group: Carboxylic acid Functional group formula: R COOH The carboxylic acid function group is a carbonyl attached to an OH group Naming convention: Carboxylic acid compounds have oic acid at the end of their name e.g. propanoic acid Example compound: Propanoic acid The carboxylic acid functional group is located at the end of a compound (or a branch point), as it contains one R-group

16 Chemical properties of carboxylic acid Common carboxylic acid containing compounds Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin Cummings Chemical name: Methanoic acid Common name: Formic acid Found in: Bee stings Chemical name: Ethanoic acid Common name: Acetic acid (acetate) Found in: Vinegar Part of acetyl CoA Chemical name: Butanoic acid Common name: Butyric acid Found in: Off butter

17 Chemical properties of carboxylic acid Carboxylic acid compounds are weak acids Donate their H + to a base compound ~5% of the time Below is an example of how a carboxylic acid compound behaves in an acid-base reaction + H 2 O + H 3 O + Ethanoic acid Conjugate base of ethanoic acid Hydronium ion

18 Chemical properties of carboxylic acid Animation of a carboxylic acid donating H + in an acid-base reaction H H H Ethanoic acid C O C H + Conjugate base of ethanoic acid + OH - H 32 O + Hydronium ion Once ethanoic acid donates its H + to H 2 O, the oxygen that was previously attached to the H + becomes negatively charged within the conjugate base compound. H 2 O is converted into the hydronium ion (H 3 O + ) which is the conjugate acid.

19 Part 1: Exploring carbonyl containing functional groups Hydrocarbon derivatives Hydrocarbon derivatives are compounds that contain atoms such as oxygen, nitrogen, fluorine or chlorine as well as carbon and hydrogen atoms The carbonyl group A carbonyl group is made up of a carbon atom that forms a double bond to an oxygen atom While the carbonyl group itself is not a functional group, it is part of many functional groups including the aldehyde and ketone groups Chemical properties of ketones The ketone functional group is a carbonyl attached to two R-groups The ketone functional group is located in the middle of compounds, as it contains two R-groups Ketone containing compounds have one at the end of their names e.g. propanone

20 Part 1: Exploring carbonyl containing functional groups Chemical properties of aldehydes The aldehyde functional group is a carbonyl attached to a hydrogen The aldehyde functional group is located at the end of a compound (or a branch point), as it contains one R-group Aldehyde containing compounds have al at the end of their names e.g. propanal Chemical properties of carboxylic acids The carboxylic acid functional group is a carbonyl attached to an OH group The carboxylic aicd functional group is located at the end of a compound (or a branch point), as it contains one R-group Carboxylic acid containing compounds have oic acid at the end of their names e.g. propanoic acid Carboxylic acid groups behave like weak acids, donating their H + ~5% of the time to a base

21 Part 2: Redox reactions involving functional groups Redox reactions Breakdown of alcohol in the liver

22 Redox reactions Combustion reactions are the most common type of chemical reaction Combustion reactions always involve a substance reacting with oxygen When organic hydrocarbons like methane (CH 4 ) combust: Water, carbon dioxide and energy (light and heat) are produced CH 4 + 2O 2 CO 2 + 2H 2 O + energy All combustion reactions are redox reactions

23 Redox reactions Electrons H atoms O atoms OXIDATION Loss of electrons Loss of H atoms Gain of O atoms REDUCTION Gain of electrons Gain of H atoms Loss of O atoms OXIDATION: Loss of 1 or more hydrogen atoms REDUCTION: Gain of 1 or more hydrogen atoms Losing or gaining hydrogen atoms is equivalent to losing or gaining electrons Each hydrogen atom contains 1 electron (and 1 proton) Oxidation and reduction are complementary processes Oxidation and reduction occur simultaneously because the compound that loses hydrogen (oxidation) donates it to another compound which accepts the hydrogen (reduction) H 1p+ 1e -

24 Redox reactions In a redox reaction, electrons and/or hydrogen atoms are transferred from one compound to another OIL RIG useful to remember what happens in a redox reaction: Oxidation Is Loss of electrons and/or hydrogen atoms (OIL) Reduction Is Gain of electrons and/or hydrogen atoms (RIG)

25 Redox reactions O 2 gains hydrogen = reduced CH + 4 2O 2 CO + 2 2H 2 O CH 4 loses hydrogen = oxidised In a redox reaction, one reactant is oxidised and one is reduced To determine which reactant is oxidised and which is reduced: Assess how each reactant changes during the chemical reaction by looking at the products The reactant that has lost hydrogen to become the product has been oxidised The reactant that has gained hydrogen to become the product has been reduced

26 Redox reactions Coenzyme gains 2 hydrogens = reduced Biological molecule loses 2 hydrogens = oxidised In a redox reaction, one reactant is oxidised and one is reduced Adapted from Timberlake 2013, p

27 Redox reactions Redox reaction are vital to many metabolic pathways required to generate cellular energy (ATP) including: Glycolysis Citric acid cycle The electron transport chain Also required to breakdown alcohol in the liver Electron poor coenzymes Electron rich coenzymes The coenzymes that are commonly used in redox reactions (within metabolic pathways) can exist in either: An electron/hydrogen rich form An electron/hydrogen poor form NAD + NADH NADP NADPH FAD FADH 2 Adapted from Timberlake 2013, p

28 Redox reactions NAD + gains hydrogen = reduced Malate-H + NAD + Oxaloacetate + NADH Malate-H loses hydrogen = oxidised Malate-H loses hydrogen to become oxaloacetate, hence Malate-H is oxidised Oxidation is loss of hydrogen/electrons NAD + gains hydrogen to become NADH, hence NAD + is reduced Reduction is gain of hydrogen/electrons

29 Redox reactions Aldehydes are readily oxidised in a redox reaction The aldehyde group contains a hydrogen atom which can be lost via an oxidation reaction Ketones cannot be oxidised in a redox reaction The Ketone group does not contain any hydrogen atoms that can be lost via an oxidation reaction Aldehyde compound Oxidised Carboxylic acid compound Ketone compound Resists oxidation

30 Attempt Socrative questions: 1 and 2 Google Socrative and go to the student login Room name: City name followed by 1 or 2 (e.g. PERTH1) 1 for 1 st session of the week and 2 for 2 nd session of the week

31 Breakdown of alcohol in the liver ETHANOL CONSUMED IN AN ALCOHOLIC BEVERAGE Once in the blood CREATE CELLULAR ENERGY (ATP) IN THE COMMON METABOLIC PATHWAY Used to ETHANOL IS TRAFFICKED TO THE LIVER TO BE BROKEN DOWN VIA TWO REDOX REACTIONS Result ETHANOIC ACID (ACETATE) IS THE LAST PRODUCT OF ALCOHOL BREAKDOWN Converted to ACETYL COA

32 Breakdown of alcohol in the liver Once in the liver ethanol is broken down via two redox reactions Frist redox reaction: The oxidation ethanol (alcohol) generates acetaldehyde (aldehyde) Second redox reaction: The oxidation acetaldehyde (aldehyde) generates acetate (carboxylic acid) Redox reaction 1 Redox reaction 2 Ethanol Acetaldehyde Acetate Alcohol functional group Aldehyde functional group Carboxylic acid functional group

33 Breakdown of alcohol in the liver First redox reaction in the breakdown of alcohol: Ethanol is readily oxidised to acetaldehyde in a redox reaction facilitated by the alcohol dehydrogenase enzyme The alcohol functional group is oxidised to an aldehyde group The OH group in ethanol loses its hydrogen atom, resulting in the oxygen atom forming a double bond to the carbon atom Ethanol loses hydrogen = oxidised Alcohol dehydrogenase + NAD + NADH Acetaldehyde (ethanal) Aldehyde group + Ethanol NAD + gains hydrogen = reduced

34 Breakdown of alcohol in the liver Animation of the first alcohol breakdown reaction H Acetaldehyde H O H C C H H H Ethanol Electron rich coenzyme + NADH + Electron poor coenzyme Ethanol loses two hydrogen atoms (oxidised) which are accepted by NAD + (reduced). NAD + becomes NADH by accepting the hydrogen atoms. After being oxidised ethanol becomes acetaldehyde.

35 Breakdown of alcohol in the liver Second redox reaction in the breakdown of alcohol: Acetaldehyde is readily oxidised to acetate in a redox reaction facilitated by the acetaldehyde dehydrogenase enzyme The aldehyde functional group is oxidised to a carboxylic acid group The hydrogen atom within the aldehyde group is lost before being replaced by an OH group from H 2 O Acetaldehyde loses hydrogen = oxidised Acetaldehyde dehydrogenase + NAD NADH acetate (ethanoic acid) Acetaldehyde (ethanal) NAD + gains hydrogen = reduced

36 Breakdown of alcohol in the liver Animation of the second alcohol breakdown reaction H Acetate H O C C H Electron rich coenzyme O NADH H H H Acetaldehyde Electron poor coenzyme Acetaldehyde loses one hydrogen atom (oxidised) which is accepted by NAD + (reduced). NAD + becomes NADH by accepting hydrogen atoms. After losing hydrogen atoms acetaldehyde accepts an OH group from H 2 O to become acetate.

37 Breakdown of alcohol in the liver ALCOHOL IS TOXIC TO THE BODY THE AMOUNT OF ALCOHOL IN THE BLOOD (CONCENTRATION) DICTATES HOW INEBRIATED THE INDIVDIUAL FEELS MOST INDIVIDUALS BREAKDOWN ONE STANDARD DRINK PER HOUR THE LIVER CONTAINS SPECIFIC ENZYMES NEEDED TO BREAKDOWN ALCOHOL THE BODY TRAFFICKS ALCOHOL TO THE LIVER TO BE BROKEN DOWN TO ALLIAVIATE THE EFFECTS OF ALCOHOL ACETATE IS CONVERTED INTO ACETYL COA TO BE USE IN METABOLIC REACTIONS REDOX REACTIONS IN THE LIVER BREAKDOWN ALCOHOL INTO ACETATE

38 Breakdown of alcohol in the liver Specific enzymes are required to breakdown alcohol in the liver The toxic ethanol compound is converted into an even more toxic compound called acetaldehyde via oxidation Requires the alcohol dehydrogenase enzyme The acetaldehyde compound is broken down into the non-toxic acetate compound via oxidation Requires the acetaldehyde dehydrogenase enzyme Acetate is converted into acetyl CoA before it is used in metabolic reactions such as the common metabolic pathway (to make ATP) Alcohol dehydrogenase Ethanol Acetaldehyde Acetate Alcohol functional group Aldehyde functional group Acetaldehyde dehydrogenase Carboxylic acid functional group

39 Breakdown of alcohol in the liver Acetaldehyde is responsible for many of the undesirable affects of drinking alcohol The build-up of acetaldehyde in the blood can cause: Headache Nausea and vomiting Dehydration Alcohol dehydrogenase Ethanol Acetaldehyde Acetate Alcohol functional group Aldehyde functional group Acetaldehyde dehydrogenase Carboxylic acid functional group

40 Breakdown of alcohol in the liver Why do people of Asian ethnicity often get a red flush when drinking alcohol? Asians often have a gene variant that produces a less efficient acetaldehyde enzyme Slows down the conversion of acetaldehyde into acetate Acetaldehyde is more likely to build-up and cause problems in those of Asian ethnicity Acetaldehyde dilates the blood vessels in the skin causing reddening Often also causes a rapid heart beat Women have less acetaldehyde enzyme than men Consequently, women breakdown alcohol more slowly than men Alcohol dehydrogenase Ethanol Acetaldehyde Acetate Alcohol functional group Aldehyde functional group Acetaldehyde dehydrogenase Carboxylic acid functional group

41 Key concept: reactivity of functional groups Why is it necessary for the body to take alcohol to the liver once it enters the blood? What are the functional group changes that allow alcohol breakdown to occur? What type of chemical reaction facilitates these changes? Why are people of Asian ethnicity often more affected by alcohol than others? Explain.

42 Attempt Socrative questions: 3 to 6 Google Socrative and go to the student login Room name: City name followed by 1 or 2 (e.g. PERTH1) 1 for 1 st session of the week and 2 for 2 nd session of the week

43 Part 2: Redox reactions involving functional groups Redox reactions A redox reaction involves one reactant being oxidised and one reactant being reduced Oxidation and reduction occur simultaneously in a redox reaction Oxidation is the loss of electrons and/or hydrogen atoms Reduction is the gain of electrons and/or hydrogen atoms OIL RIG: Oxidation Is Loss, Reduction Is Gain The reactant that has loses hydrogen to become the product has been oxidised The reactant that has gains hydrogen to become the product has been reduced

44 Part 2: Redox reactions involving functional groups Breakdown of alcohol in the liver Ethanol is trafficked to the liver to be broken down via two redox reactions Ethanol (alcohol functional group) is oxidised to acetaldehyde (aldehyde functional group) in the first alcohol breakdown redox reaction Acetaldehyde (aldehyde functional group) is oxidised to acetate (carboxylic acid functional group) in the second alcohol breakdown redox reaction The coenzyme NAD + removes hydrogen atoms from the compounds via oxidation in the alcohol breakdown redox reactions Acetate is converted to acetyl CoA to be used in metabolism to generate cellular energy (ATP) Specific enzymes are needed to facilitate the alcohol breakdown redox reactions Individuals of Asian ethnicity often have a less efficient acetaldehyde dehydrogenase enzyme, meaning they breakdown alcohol more slowly and experience the side-effects to a greater extent

45 Part 3: Exploring the ester and phenol functional groups Chemical properties of esters TAG contains ester connections Chemical properties of phenols Free radicals

46 Chemical properties of esters Functional Group: Ester Functional group formula: R COO R The ester functional group is a carbonyl attached to an oxygen and two R-groups Naming convention: Ester compounds have anoate at the end of their name e.g. methyl propanoate Example compound: Methyl propanoate The ester functional group is located in the middle of compounds, as it contains two R-groups

47 Functional Groups Functional groups can have one or two R-groups attached Single R-group functional groups are always found at the end of a compound or at a branch point within a compound Example: R-OH = alcohol functional group Two R-group functional groups are always found in the middle of a compound and are often used to connect two compounds together Example: R-O-R = ether functional group 1 R-group functional group: alcohol OH R 2 R-group functional group: ether R O R R represents any atom or group of atoms capable of attaching to the functional group OH is the group of atoms within the alcohol functional group R represents any atom or group of atoms capable of attaching to the functional group O is the atom that makes up the ether functional group R represents any atom or group of atoms capable of attaching to the functional group

48 1 R-group functional group: alcohol R OH 2 R-group functional group: ether R O R R represents any atom or group of atoms capable of attaching to the functional group OH is the group of atoms within the alcohol functional group R represents any atom or group of atoms capable of attaching to the functional group O is the atom that makes up the ether alcohol functional group R represents any atom or group of atoms capable of attaching to the functional group R Functional group in the middle of a compound between two R-groups R

49 TAG contains ester connections The fats and oils in our diet are made up of the lipid triacylglycerol (TAG) TAG contains one glycerol and three fatty acids Glycerol Alcohol functional group Triacylglycerol Glycerol contains the alcohol functional group Fatty acids contain the carboxylic acid functional group The fatty acids are connected to glycerol in TAG via an ester functional group Fatty acid Carboxylic acid functional group Ester functional group

50 TAG contains ester connections Ester hydrolysis (Removing the ester) Triacylglycerol + H 2 O Glycerol + 3 fatty acids Esterification (Creation of an ester)

51 TAG contains ester connections Esterification is required to connect fatty acids to glycerol when generating new TAGs New TAGs are created inside cells for fat storage Ester hydrolysis is required to breakdown TAG into individual compounds Three fatty acids One glycerol TAGs must be broken down before they can be metabolised to create cellular energy (ATP)

52 Chemical properties of esters Esterification reaction Creation of an ester functional group: An alcohol and carboxylic functional group react to create an ester functional group, while releasing a H 2 O molecule Alcohol + carboxylic acid ester The oxygen within the alcohol compound forms a new bond to the carbonyl within the carboxylic acid compound to create a larger ester compound Methanol Ethanoic acid Methyl ethanoate + + Alcohol functional group Carboxylic acid functional group Ester functional group

53 Chemical properties of esters Animation of an ester formation via an esterification reaction Methyl ethanoate H H H C O Methanol Ester + O H HO C C Ethanoic acid H H H Methanol loses a hydrogen atom and ethanoic acid loses an OH group. The atoms lost from the compounds come together to form water. A new covalent bond is formed between oxygen and carbon to create an ester group which forms the methyl ethanoate compound.

54 Chemical properties of esters Ester hydrolysis reaction Breakdown of an ester functional group: An ester is broken into one alcohol and one carboxylic acid compound, with the extra atoms needed to regenerate the functional groups come from a H 2 O molecule Ester alcohol + carboxylic acid The oxygen within the ester compound forms a new bond to a hydrogen atom to create an alcohol compound The carbonyl within the ester compound forms a new bond to an OH group to create a carboxylic acid compound Methyl ethanoate Methanol Ethanoic acid + + Ester functional group Alcohol functional group Carboxylic acid functional group

55 Chemical properties of esters Animation of an ester breakdown via an Ester hydrolysis reaction O + H H H H H Methyl ethanoate C Methanol O H H O O C Alcohol C H H H Carboxylic acid Ethanoic acid The covalent bond connecting oxygen to the carbonyl within the ester group is broken. The oxygen forms a new bond with a hydrogen atom from H 2 O to create methanol. The carbonyl forms a new bond with the OH group from H 2 O to create ethanoic acid.

56 Key concept: esters What functional groups do glycerol and fatty acids contain? How do these functional groups assist in creating the ester functional group? Does esterification assist in building or breaking down triacylglycerol? Explain. Why is a H 2 O molecule required during an ester hydrolysis reaction?

57 Attempt Socrative questions: 7 and 8 Google Socrative and go to the student login Room name: City name followed by 1 or 2 (e.g. PERTH1) 1 for 1 st session of the week and 2 for 2 nd session of the week

58 Chemical properties of phenols Functional Group: Phenol Functional group formula: The phenol functional group is benzene ring attached to a OH group, with five positions where other atoms or groups of atoms can attach Naming convention: Phenol compounds have phenol at the end of their name e.g. Methylphenol Example compound: Methylphenol

59 Chemical properties of phenols The phenol functional group has 6 carbon atoms, 5 of which bond to a single hydrogen atom The hydrogen atoms within the benzene ring can be replaced by another atom or group of atoms via a chemical reaction Allows other atoms to connect to the phenol functional group Phenol group Phenol group containing compound Phenol group containing compound

60 Chemical properties of phenols Phenol is a toxic compound Phenol is toxic to the liver Ingestion can be fatal Phenol Concentrated essential oils (such as clove oil) contain phenols Cause skin and mucous membrane irritation Can result in dermatitis and severe burns

61 Chemical properties of phenols Compounds that contain the phenol functional group often have beneficial properties Some are used as antiseptics such as those used in mouthwashes Can be used as flavour enhances Some phenol containing compounds are antioxidants, which protect the body against free radicals Polyphenols and vitamin E Polyphenols are present in commonly consumed foods and beverages Blue berries, cloves, dark chocolate, red wine Polyphenols can reduce blood pressure by promoting vasodilation Lower the risk of cardiovascular disease Stoker 2014, p

62 Free radicals REACTIVE OXYGEN SPECIES (AKA FREE RADICALS) Common reactive oxygen species Definition REACT READILY TO PAIR THEIR UNPAIRED ELECTRONS Superoxide: O 2 - Hydroxyl radical: OH Hydrogen peroxide: H 2 O 2 FORMED AS A BY-PRODUCT OF THE COMMON METABOLIC PATHWAY (CMP) CMP IS REQUIRED TO GENERATE CELLULAR ENERGY (ATP)

63 Free radicals FREE RADICALS PRODUCED IN THE CMP Significant amount of antioxidants present ANTIOXIDANTS REACT WITH FREE RADICALS IN A REDOX REACTION Result FREE RADICALS CONVERTED INTO SAFE, STABLE COMPOUNDS Consequence NO OXIDATIVE DAMAGE TO BIOLOGICAL MOLECUELS

64 Free radicals FREE RADICALS PRODUCED IN THE CMP Few antioxidants present FREE RADICALS REACT WITH BIOLOGICAL MOLECULES VIA REDOX REACTIONS Result OXIDATIVE DAMAGE TO DNA, PROTEIN AND THE LIPID MEMBRANE CAN LEAD TO CELL DEATH BIOMOLECULES BECOME DAMAGED, WHICH CAN LEAD TO A DISEASE STATE OVER TIME Consequence WHITE BLOOD CELLS ARE RECRUITED TO THE SITE OF OXIDATIVE DAMAGE CAUSED BY FREE RADICALS Can lead to INFLAMMATION, CARDIOVASCULAR DISEASE AND DIABETES

65 Attempt Socrative questions: 9 and 10 Google Socrative and go to the student login Room name: City name followed by 1 or 2 (e.g. PERTH1) 1 for 1 st session of the week and 2 for 2 nd session of the week

66 Part 3: Exploring the ester and phenol functional groups Chemical properties of esters The ester functional group is a carbonyl group attached to an oxygen and two R-groups Ester containing compounds have anoate at the end of their name e.g. methyl propanoate The ester functional group is located in the middle of compounds, as it contains two R-groups Ester formation involves an alcohol reacting with a carboxylic acid functional group to create an ester Ester hydrolysis involves the breakdown of an ester into two separate compounds, one alcohol compound and one carboxylic acid compound TAG contains ester connections The main lipid in dietary fats and oils is triacylglycerol (TAG) TAG is made up of three fatty acids and one glycerol The alcohol groups in glycerol reacts with the carboxylic acid group in fatty acids to create an ester connection TAG contains three ester connections that connect the three fatty acids to one glycerol

67 Part 3: Exploring the ester and phenol functional groups Chemical properties of phenols The phenol functional group is benzene ring attached to an OH group, with five positions where other atoms or groups of atoms can attach Phenol containing compounds have phenol at the end of their name e.g. methylphenol Phenol is toxic to the liver Many antiseptics are phenol containing compounds Antioxidants like polyphenols and vitamin E both contain the phenol group Free radicals Reactive oxygen species (aka free radicals) react readily to pair their unpaired electrons to become more stable Free radicals are formed as a by-product of normal metabolic reactions Antioxidants react with free radicals in a redox reaction, which stabilises the free radical Without enough antioxidants, free radicals can cause oxidative damage via redox reactions to important biological molecules, which can lead to a disease state overtime

68 Readings & Resources Stoker, HS 2014, General, Organic and Biological Chemistry, 7 th edn, Brooks/Cole, Cengage Learning, Belmont, CA. Stoker, HS 2004, General, Organic and Biological Chemistry, 3 rd edn, Houghton Mifflin, Boston, MA. Timberlake, KC 2014, General, organic, and biological chemistry: structures of life, 4 th edn, Pearson, Boston, MA. Alberts, B, Johnson, A, Lewis, J, Raff, M, Roberts, K & Walter P 2008, Molecular biology of the cell, 5 th edn, Garland Science, New York. Berg, JM, Tymoczko, JL & Stryer, L 2012, Biochemistry, 7 th edn, W.H. Freeman, New York. Dominiczak, MH 2007, Flesh and bones of metabolism, Elsevier Mosby, Edinburgh. Tortora, GJ & Derrickson, B 2014, Principles of Anatomy and Physiology, 14 th edn, John Wiley & Sons, Hoboken, NJ. Tortora, GJ & Grabowski, SR 2003, Principles of Anatomy and Physiology, 10 th edn, John Wiley & Sons, New York, NY.