1. Lecture 3 : How Matter is Organized Chemistry is the science of the structure and interactions of matter. –all living things consist of matter. Matter is anything that occupies space. –mass is the amount of matter in any object. –weight is the force of gravity acting on matter. In outer space, weight is close to zero, but mass remains the same as on Earth.

2. Chemical Elements Elements are substances that can not be split into simpler substances by ordinary means. –92 elements exist in nature –26 of naturally occurring elements are in the body –represented by chemical symbols ( first 1-2 letters of name )Na Natrium=Sodium 4 elements form 96 % of the body’s mass –hydrogen, oxygen, carbon and nitrogen Trace elements are present in tiny amounts –such as copper,selenium & zinc

3. Structure of Atoms Atoms are the smallest units of matter that retain the properties of an element Atoms consist of 3 types of subatomic particles –protons, neutrons and electrons Nucleus contains protons (p+) & neutrons (neutral charge) Electrons (e-) surround the nucleus as a cloud ( electron shells are designated regions of the cloud)

4. Electron Shells Most likely region of the electron cloud in which to find electrons orbiting the nucleus Each electron shell can hold only a limited number of electrons –first shell can hold only 2 electrons –2nd shell can hold 8 electrons –3rd shell can hold 18 electrons –higher shells (up to 7) hold many more electrons Number of electrons = number of protons Each atom is electrically neutral; charge = 0

5. Atomic Number & Mass Number Atomic number is number of protons in the nucleus. Mass number is the sum of its protons and neutrons.

6. Ions, Molecules, & Compounds Ions are formed by ionization –an atom that gave up or gained an electron –written with its chemical symbol and (+) or (-) Molecule –molecules = when 2 of the same atoms share electrons –compound = when 2 or more different atoms share electrons –written as molecular formula showing the number of atoms of each element (H2O)

7. Chemical Bonds Bonds hold together the atoms in molecules and compounds An atom with a full outer electron shell is stable and unlikely to form a bond with another atom Octet rule states that biologically important elements interact to produce chemically stable arrangements of 8 electrons in the valence shell. Whether electrons are shared, lost or gained determines the types of bonds formed

8. Free Radicals Atom with an unpaired electron in its outmost shell Unstable and highly reactive Can become stable – by giving up electron –taking one off another molecule (breaking apart important body molecules)

9. Free Radicals & Your Health Produced in your body by absorption of energy in ultraviolet light in sunlight, x-rays, by breakdown of harmful substances, & during normal metabolic reactions, fried foods, smoking, drugs, exercise. Linked to many diseases -- cancer, diabetes, Alzheimer, atherosclerosis and arthritis Damage may be slowed with antioxidants such as vitamins C and E, selenium & beta- carotene (precursor to vitamin A). Increased serum thiol levels with spinal adjustments.

10. Atoms achieve stability by gaining, losing or sharing electrons to fill their outermost energy level. The interaction often involves the formation of chemical bonds which hold the participating atoms together once the reaction has ended. 3 basic types of chemical bonds 1) Ionic 2) Covalent 3) Hydrogen

11. Bonds continued When chemical bonding occurs, the result is the creation on NEW CHEMICAL ENTITIES called MOLECULES and COMPOUNDS. Molecule refers to any chemical structure consisting of atoms held together by a COVALENT BOND. Compound is any chemical substance made of atoms or 2 or more elements regardless of the bond. Not all compounds consist of molecules. Salt (NaCl) held together by ionic bond. Water=H2O is a compound. It contains 2 elements Hydrogen and Oxygen held by covalent bond

12. Ionic Bonds Positively (cations) and negatively charged ions (anions) attract each other to form an ionic bond Atoms become ions by losing or gaining electrons We assign + to charge on proton and - to charge on electron. In the body, ionic bonds are found mainly in teeth and bones An ionic compound that dissociates in water into + and - ions is called an electrolyte( Na+Cl-)salt

13. The Ionic Bond in Sodium Chloride Sodium loses an electron to become Na+ (cation) Chlorine gains an electron to become Cl- (anion) Na+ and Cl- are attracted to each other to form the compound sodium chloride (NaCl) -- table salt Ionic compounds generally exist as solids

14. Covalent Bonds Some atoms can complete there outer shells not by gaining or losing electrons but by SHARING. Individual Hydrogen atoms DON’T exist in nature. Instead we find H molecules. Molecular H consists of a PAIR of H atoms. In chemical shorthand Molecular hydrogen = H2. H is symbol for Hydrogen and the subscript 2 indicates the number of atoms.

15. Covalent Bonds Atoms share electrons to form covalent bonds Electrons spend most of the time between the 2 atomic nuclei –single bond = share 1pair –double bone = share 2 pair –triple bond = share 3 pair Polar covalent bonds share electrons unequally between the atoms involved

16. Polar Covalent Bonds Unequal sharing of electrons between atoms. In a water molecule, oxygen attracts the hydrogen electrons more strongly so the electrons spend more time orbiting the oxygen nucleus than orbiting the hydrogen nucleus –Oxygen has greater electronegativity as indicated by the negative Greek delta sign.

17. Hydrogen Bonds Covalent & ionic bonds tie atoms together to form molecules and compounds. Other WEAK forces also act between adjacent molecules and even between atoms within a large molecule. The MOST IMPORTANT OF THESE WEAK ATTRACTIVE FORCES is the HYDROGEN BOND. A HYDROGEN BOND is the attraction between + on the HYDROGEN atom of a polar covalent bond and a – on an oxygen or nitrogen atom of another polar covalent bond. Hydrogen bonds are to weak to create molecules but can change molecular shape. Surface tension( insects )

18. States of Matter Matter exists as either SOLID, LIQUID or GAS. Solids maintain their volume and their shape at ordinary temperature and pressure. Liquids have a constant volume but no fixed shape. Gas has neither a constant volume nor fixed shape. WATER is the only substance that can exist as ALL 3.

19. Lecture 4 BASIC ENERGY CONCEPTS To understand the relationship between MATTER and ENERGY it’s essential to discuss chemical reactions. WORK- Movement of an object or change in the physical structure of matter ( walking or running) ( converting water to water vapor) ENERGY- Capacity to perform work. Need energy to do work. Kinetic energy- energy in motion. Falling off ladder, it’s kinetic energy that does damage. Potential energy- stored energy that has potential to do work. The potential energy in batteries is converted into kinetic energy that vibrates sound producing membranes of headset of I-POD.

20. Potential  Kinetic Energy Cells perform work as they synthesize complex molecules into, out of, and within the cell. Cells of skeletal muscle at REST have potential energy in the form of protein filaments and the covalent bonds between molecules inside the cells. When the muscle contracts it performs work. Potential energy is converted into kinetic energy and HEAT IS RELEASED. As a result when you exercise, your body temperature rises.

21. Thermodynamic laws Energy can’t be created or destroyed Energy can only be converted from one form to another. The conversion is never 100% efficient. Each time energy exchange occurs some energy is released into non useable form.

22. TYPES of chemical reactions 3 types of chemical reactions. Decomposition Synthesis Reaction ( exchange/reversible )

23. Decomposition Reactions-- Catabolism Large molecules are split into smaller atoms, ions or molecules All decomposition reactions occurring together in the body are known as catabolism Usually are exergonic since they release more energy than they absorb

24. Catabolism AB  A + B When you eat a meal of Proteins, Fats, and Sugars which are too complex to be absorbed, decomposition reactions in the digestive tract break down these molecules. Decomposition involving water is important in breakdown of complex molecules. HYDROLYIS is taking: H 2 0  H + OH When a covalent bond is broken, it releases kinetic energy that can perform the work. When the energy is released cells perform vital functions.

25. Synthesis Reactions--Anabolism Two or more atoms, ions or molecules combine to form new & larger molecules All the synthesis reactions in the body together are called anabolism Usually are endergonic because they absorb more energy than they release Ex: The formation of water from hydrogen and oxygen molecules. DEHYDRATION SYNTHESIS or condensation is formation of a complex molecule by the REMOVAL of WATER. The opposite of hydrolysis.

26. Exchange Reactions Substances exchange atoms –consist of both synthesis and decomposition reactions Example –HCl + NaHCO3  H2CO3 + NaCl –ions have been exchanged between substances

27. Reversible Reactions Chemical reactions can be reversible. –Reactants can become products or products can revert to the original reactants Indicated by the 2 arrows pointing in opposite directions between the reactants and the products AB A + B

28. Reversible Reactions This is important with acid & bases to balance the pH. If you take carbonic acid and add OH then your left with bicarbonate ( base). H 2 CO 3  HCO 3 If we take Bicarcbonate and add H then we end up with carbonic acid. HCO 3  H 2 CO 3 Below is a type of response to pH in body fluids. C0 2 + H 2 O  H 2 CO 3  HCO 3 + H  

29. Inorganic Compounds & Solvents Most of the chemicals in the body are compounds Inorganic compounds –usually lack carbon & hydrogen are structurally simple –water, carbon dioxide (a by-product of cell metabolism), oxygen (important in metabolic reaction,) acids, bases and salts (compounds held together by IONIC BONDS ) Organic compounds –contain carbon & hydrogen –always have covalent bonds

30. WATER PROPERTIES We will be concerned primarily with water and how its properties are essential for life. Most of the other inorganic molecules exist in association with water. Both carbon dioxide and oxygen for example are gas molecules that are transported in body fluids. All inorganic acids, bases and salts dissolve in body fluids as well. Water is known as the universal SOLVENT

31. Water Water makes up about 2/3 of total body weight. The bonds in water are oriented in such a way that the hydrogen atoms are close together. As a result the water molecule has a (+) and (–) poles. Water is called POLAR MOLECULE. Many inorganic compounds are held together by ionic bonds. In water these COMPOUNDS undergo IONIZATION = dissociation. Aqueous solution containing +/- ions will conduct electrical current. + & - move toward each other. Many inorganic/organic molecules will dissolve in water=solution. The medium in which other atoms, ions molecules are dispersed is called the solvent. The dispersed substances are the solute.

32. Water Functions Heat capacity is high. It can absorb a large amount of heat with only a small increase in its own temperature. large number of hydrogen bonds in water –bonds are broken as heat is absorbed instead of increasing temperature of water. The cohesive nature of water molecules allows blood and body fluids to flow smoothly through vessels and tissue spaces and allows for uniform distribution of solutes. Major component of lubricating fluids within the body –mucus in respiratory and digestive systems –synovial fluid in joints –serous fluids in chest and abdominal cavities organs slide past one another

33. Electrolytes Soluble inorganic molecules whose ions conduct an electrical current in solution are electrolytes. NaCl is an electrolyte. Changes in the concentration of electrolytes in body will effect every vital function. Ex: decreased potassium levels will lead to general muscular paralysis and increased levels will cause weak or irregular hear beats. The balance (homeostasis) is regulated by Kidneys ( ion excretion) the digestive tract (ion absorption) and skeletal system (ion storage or release)

34. Electrolytes + IONS (Cations) - IONS (Anions) Na - Sodium Cl K - Potassium HCO 3 – Bicarbonate Ca - Calcium HPO 4 – Phosphate Mg - Magnesium SO 4 – Sulfate PROTEINS These are used in acid/base balance and action potentials.

35. Hydrophilic & Hydrophobic Compounds Some organic molecules contain polar covalent bonds which also attract water molecules. The hydration spheres that form may then carry these molecules into SOLUTION. Molecules such as GLUCOSE ( an important soluble sugar) that interact readily with water is called HYDROPHILIC. (Water- Loving)

36. Hydrophobic When organic molecules lack polar covalent bonds or have few. These molecules don’t have + or – terminals and are said to be non polar. The most familiar hydrophobic molecule are fats and oils of all kinds. Think of what happens if you spill gasoline or oil in ocean. They form slicks instead of dissolving.

37. Inorganic Acids, Bases & Salts Acids, bases and salts always dissociate into ions if they are dissolved in water –acids dissociate into H+ and one or more anions –bases dissociate into OH- and one or more cations –salts dissociate into anions and cations, none of which are either H+ or OH- Acid & bases react in the body to form salts Electrolytes are important salts in the body that carry electric current (in nerve or muscle)

38. ACID and BASES The human body can only remain healthy if it’s fluids exist within a narrow band of pH. The pH scale measures the relative concentration of HYDROGEN H+ and HYDROXIDE OH-. The pH scale goes from 0-14 0-6.9 is ACID: stomach HCL, beer, wine, tomatoes saliva ( contains more Hydrogen than Hydroxide) pH of 7 = neutral ( equal # of Hydrogen & Hydroxide) pH above 7 = Base ( more Hydroxide than Hydrogen) blood, ocean water, bleach, ammonia (7.35-7.45 blood) Should eat more alkaline FORMING foods to remain healthier. Diet should have little acid forming foods. 80% alkaline foods and 20% acidic foods

39. Acid/ Base The strength of acid/base is determined by the ability of the substances to dissociate into individual ions. HCL( hydrochloric acid) ( muriatic acid)  H+ Cl- Can lower the pH of pools NaOH (sodium hydroxide) Strong base-----  Na+ + OH- Strong bases have industrial uses like drano. If acid or base is swallowed the UNIVERSAL ANTIDOTE is RAW EGG WHITES, WATER & MILK. Then take to hospital for further evaluation. Never vomit the acids up. You will damage the tissues a second time.

40. Buffer Systems of the Body Body fluids vary in pH but the range of each is limited and is maintained by a variety of buffering systems. –gastric juice 1.2 to 3.0; saliva 6.35 to 6.85; bile 7.6 to 8.6 and blood 7.35 to 7.45 Buffers stabilize the pH of a solution by removing or replacing hydrogen ions. They involve a WEAK ACID and its related salt. –carbonic acid - bicarbonate buffer system NaHCO3 otherwise known as baking soda. Alka-Seltzer can neutralize the acid in the stomach. –HCL + NaOH -  H2O + NaCl –This reaction produces water and salt. By adding HCL you neutralize both the strong acid and strong base.

41. Carbonic Acid Bicarbonate Buffering System Carbonic Acid H2CO 3 Bicarbonate HCO3 If you add H which is an ACID it will go to the BASE to make it less basic or more acidic. If there is HCO 3 in a flask of water and you add H, the result is H2CO 3 ADD H HCO 3  H2CO 3 A base became an acid ADD OH H 2 CO 3  HCO 3 A acid became a base

42. Lecture 5 -Organic Compounds Always contain carbon and hydrogen & generally Oxygen Usually long chain of Carbon atoms linked by covalent bonds The carbon atoms typically form additional bonds with Hydrogen or Oxygen. Make up 40% of body mass. 4 Main Classes: Carbs, Lipids, Proteins, and Nucleic Acids.

43. Functional groups of Organic Compounds Carboxyl Group –COOH : Acts as an acid, releasing H bonds to become R…--COO - Examples are Fatty acids and Amino Acids Amino Group –NH2 Can accept or release H bonds depending on the pH. An example are Amino acids Hydroxyl Group –OH Strong base dissociate to release hydroxide ions ( OH-) Examples Carbohydrates, amino acids, and fatty acids. Phosphate Group –PO4 Links other molecules to form larger structures. Stores energy in high NRG bonds. Example: phospholipids, nucleic acids.

44. Isomers have same molecular formulas but different structures (glucose & fructose are both C6H12O6 STRUCTURAL FORMULA OF GLUCOSE Isomers

45. Carbohydrates Sugars and Starches that make up roughly ½ of U.S. diet. Important for energy sources that are catabolized rather than stored. 3 sizes of carbohydrate molecules –monosaccharides –disaccharides –polysaccharides

46. Carbohydrates Diverse group of substances formed from C, H, and O –ratio of one carbon atom for each water molecule (carbohydrates means “watered carbon”) –glucose is 6 carbon atoms and 6 water molecules (H20) Main function is source of energy for ATP formation Forms only 1 % of total body weight –glycogen is storage form of glucose in liver and muscle tissue –sugar building blocks of DNA & RNA (deoxyribose & ribose sugars) C 6 H 12 O 6 - Glucose

47. Monosaccharides Called simple sugars Contain 3 to 7 carbon atoms We can absorb only 3 simple sugars without further digestion in our small intestine –glucose found in syrup or honey (metabolic fuel) –fructose found in fruit –galactose found in dairy products

48. Disaccharides Formed by combining 2 monosaccharides by dehydration synthesis (releases a water molecule) –sucrose (table sugar)= glucose & fructose –Maltose(beer) = glucose & glucose –Lactose(dairy) = glucose & galactose (lactose intolerance) –ALL carbs except monosaccharides need to be broken down by hydrolysis before they can provide useful energy. –Sugars are stored as fat for energy. ( artificial sweeteners can’t be broken down)

49. Polysaccharides- 3 Complex Carbohydrates Contain 10 or 100’s of monosaccharides joined by dehydration synthesis. STARCH: The storage form of glucose in plants. High concentrations of glucose in plant or animal cells is TOXIC. Surplus stores of glucose is converted to starch for safety. Glycogen is the storage form of glucose in animals. Glycogen is stored in the liver (hepatocytes) and in muscle cells. If serum glucose levels fall, glycogen is converted into glucose Cellulose: can only digest small amounts via bacterial action. Cellulose is called dietary fiber. Water soluble found in fruits veggies. LOWER CHOLESTEROL. Insoluble fiber is in nuts and grains.

50. Lipids = fats Formed from C, H and O –includes Fats, oils, waxes, 18-25% of body weight Hydrophobic –insoluble in polar solvents like water BUT can combines with proteins for transport in blood (lipoproteins LDL’s, HDL’s ) They form the essential structural component of all cells. They provide twice the energy as carbs gram for gram when broken down in the body. 5 Classes: Fatty acids, eicosanoids, glycerides, steroids, phospholipids.

51. Fatty Acids Fatty acids is a long Carbon chain with a carboxylic group at the end C—C—C—C—COOH Carboxyl tells us the Carbon and a hydroxyl (-OH) group are the important structural features of fatty acids. Lauric Acid found in coconut oil. They can be saturated or unsaturated.

52. Triglycerides Neutral fats composed of a single glycerol molecule and 3 fatty acid molecules –three-carbon glycerol molecule is the backbone Very concentrated form of energy –9 calories/gram compared to 4 for proteins & carbohydrates –our bodies store triglycerides in fat cells if we eat extra food. Major source of stored energy in the body. –Fatty Acids help make up Triglycerides in 2 forms. SATURATED & UNSATURATED.

53. Triglycerides 3 fatty acids & one glycerol molecule Fatty acids attached by dehydration systhesis

54. Triglycerides continued Saturated fatty acids are found in animal products and are solid at room temperature and linked to cardiovascular dis- ease. Unsaturated Fatty Acids are liquids at room temperature and found in plants. When good unsaturated fatty acids are heated as in deep frying, oxidation of fatty acids occurs. ( olive oil, peanut oil ) Margarine is made of corn oil a polyunsaturated fatty acid. Corn oil is hydrogenated by bubbling hydrogen gas through it. Hydrogenating polyunsaturated fats produces trans fats which are harmful to the body.

55. Oils & Waxes Oils are very similar to polyunsaturated fatty acids. Oils are lipids that are liquids at room temperature. Oils we produce act as natural sun block, barrier to bacteria and lubricant for skin. Waxes- Are lipids that are solid at room temperature. Produced to protect dust particles form entering the external canal.

56. Lecture 6 Phospholipids Consists of a lipid molecule joined to a phosphate. They act as the structural component of the cell and are used by the body to emulsify fats. They have a phosphate group --PO 4 ( hydrophilic end ) They have a lipid ( Fatty Acids) ( hydrophobic end)

57. Phospholipids Composition of phospholipid molecule –a polar head a phosphate group (PO4- 3) & glycerol molecule can form hydrogen bonds with water –2 nonpolar fatty acid tails interact only with lipids Composition of cell membrane –double layer of phospholipids with tails in center –Participates in transport of lipids in plasma

58. Chemical Nature of Phospholipids headtails

59. Steroids Cholesterol- structural basis of all body steroids. We ingest it form eggs, milk, cheese, and our liver makes 80% of what we need. Bile salts-these breakdown products of cholesterol are released by the liver into the digestive tract, where they aid in fat digestion and absorption. Vitamin D- A fat soluble vitamin produced in the skin on exposure to UV radiation. Needed for bone growth and calcium absorption, and immune function. Sex hormones- Estrogen and progesterone(female) and Testosterone(male). Needed for normal sexual function Adrenocorticol hormones- Cortisol a glucocorticoid is a metabolic hormone needed to maintain blood glucose levels. Aldosterone regulates salt and water balance by working on the kidneys.

60. Fat Soluble vitamins A- ingested in orange pigmented vegetables and fruits. Converted in the retina to retinal. Part of vision. Also used to heal epithelial membranes. E- Ingested in plant products like wheat germ and green leafy vegetables. Wound healing, fertility, neutralizes free radicals, anticancer. K- Made available by humans largely by action of intestinal bacteria. Needed for blood clotting. Co-Enzyme Q10(COQ10) not a vitamin- Needed by the mitochondria for the Electron Transport Chain (ETC) for ATP production. Muscles need it!

61. Steroids All animal cells membranes contain cholesterol. HDL/LDL- Statin Drugs/Liver/Nerves/Depression It’s obtained by absorption from animal products or made within the body. Limit intake to under 300mg a day.

62. Four Ring Structure of Steroids

63. Eicosanoids Lipid type derived from a fatty acid called arachidonic acid –prostaglandins = wide variety of functions and can be blocked by NSAIDS or COX inhibitors. Regulates blood pressure Uterine contractions contribute to inflammatory response prevent stomach ulcers dilate airways regulate body temperature influence formation of blood clots –leukotrienes = allergy & inflammatory responses

64. Proteins The most abundant organic component of the body. Functions consist of: Support- Structural proteins: framework of the body providing strength. Collagen, keratin, elastin Movement- Contractile proteins needed for muscle contraction. Actin any Myosin. Transport proteins- Hemoglobin transports oxygen in blood. Lipoproteins transport lipids and cholesterol. Buffering- Assist in pH changes. Albumin acts as acid and base to prevent wide swing in Ph. Catalysis-ENZYMES accelerate chemical reactions in cells. Regulation of metabolism- growth hormone, insulin.

65. Protein function continued Defense- Tough waterproof proteins of the skin, hair, nails protect the body from hazards. Proteins called antibodies are components of the immune system, helps protect us from foreign matter. Special clotting proteins restrict bleeding after an injury to the cardiovascular system.

66. Proteins 12-20% of body weight Contain carbon, hydrogen, oxygen, and nitrogen Constructed from combinations of 20 amino acids. –dipeptides formed from 2 amino acids joined by a covalent bond called a peptide bond –polypeptides chains formed from 10 to 2000 amino acids. Levels of structural organization –primary, secondary and tertiary –shape of the protein influences its ability to form bonds

67. Amino Acid Structure Central carbon atom Amino group (NH 2 ) Carboxyl group (COOH) Side chains (R groups) vary between amino acids

68. Formation of a Dipeptide Bond Dipeptides formed from 2 amino acids joined by a covalent bond called a peptide bond –dehydration synthesis Polypeptides chains formed from 10 to 2000 amino acids.

69. Enzymes Enzymes are protein molecules that act as catalysts Enzymes usually end in suffix -ase and are named for the types of chemical reactions they catalyze Steak in dish of water at 100 degrees could take months to fully breakdown. BUT in digestive tract, it only takes hours b/c of digestive ENZYMES. Cofactor- An ion or molecule that must bind to the enzyme for reaction to occur. (Ca, Mg, Zn)

70. Enzyme Functionality Acts on only one substrate Lipases work only on lipids –speed up only one reaction Very efficient –speed up reaction up to 10 billion times faster. –Enzymes are globular proteins that contain specific areas called ACTIVE SITE. The active site will bond with the substrate. –Induced fit ( lock and key model)

71. Nucleic Acids - DNA & RNA Huge molecules containing C, H, O, N and phosphorus Each gene of our genetic material is a piece of DNA that controls the synthesis of a specific protein A molecule of DNA is a chain of nucleotides Nucleotide = 1)nitrogenous base (A-G-T-C) + 2)pentose sugar + 3)phosphate group This is DNA- Double Helix Main function is storage & transfer of info essential for synthesis of proteins.

72. DNA DeoxyriboNucleic Acid- DNA determines our characteristics of eye color, hair color, blood type. It affects aspects of body structure and function b/c DNA ENCODES the info needed to build proteins. Used to identify criminal, victim or a child’s parents –need only strand of hair, drop of semen or spot of blood

73. Main Nitrogenous Bases A=Adenine G=Guanine C=Cytosine T=Thymine Purines are Adenine & Guanine Double ringed Pyramidines Cytosine & Thymine Single ringed

74. RNA Structure Differs from DNA –single stranded –ribose sugar not deoxyribose sugar –uracil nitrogenous base replaces thymine Types of RNA within the cell, each with a specific function. Performs protein synthesis –messenger RNA- transcription –ribosomal RNA –transfer RNA-translation

75. High energy compounds To perform their vital functions, cells must use energy, obtained from breaking down organic substrates via catabolism. A high energy bond is a covalent bond whose breakdown releases the energy the cell can use. In our cells, a high NRG compound connects a phosphate group PO4 to an organic molecule. This is called PHOSPHORYLATION. AMP  ADP  ATP

76. Adenosine Triphosphate (ATP) High energy compound ATP is needed for: muscle contraction, transport of substances across cell membranes, movement of structures within cells and movement of organelles Consists of 3 phosphate groups attached to adenine & 5-carbon sugar (ribose)

77. Formation & Usage of ATP Hydrolysis of ATP (removal of terminal phosphate group by enzyme -- ATPase) –releases energy –leaves ADP (adenosine diphosphate) Synthesis of ATP –enzyme ATP synthase catalyzes the addition of the terminal phosphate group to ADP –energy from 1 glucose molecule is used during both anaerobic and aerobic respiration to create 36 to 38 molecules of ATP