Chemistry, Matter, and Life

1. Chap 1 discussed that lead to chap 2 Chemical level (levels of organization) Types of metabolism: catabolism and anabolism Requirements for life: water, O2, nutrients, heat homeostasis Chemistry, Matter, and Life Chapter 2

2. Chemistry is the science that deals with the composition of matter and the changes that may occur in the composition. • Matter includes anything that has mass and takes up space • Includes solids, liquids and gases • Our bodies are composed of matter • All matter, living and non-living, is composed of elements. • Element is the simplest form of matter • It cannot be broken down into a simpler form by ordinary chemical means • Four elements are: carbon (C); oxygen (O); hydrogen (H), and nitrogen (N) make up 95% of the human body weight • Chemical symbols are abbreviations used to identify elements

3. Atoms-An element is composed of atoms that are all of the same kind. An atom is the smallest particle of an element that still retains the properties of that element. An atom is made up of still smaller subunits or particles called protons, neutrons, and electrons. A dense region called the nucleus contains the protons and neutrons.

4. Although an atom is the smallest unit of an element, it is made up of smaller subunits or subatomic particles • These smaller units are: electrons, protons and neutrons. These particles have different properties. • Electrons are tiny, very light particles that have a negative electrical charge (-). They are located in the space surrounding the nucleus (called energy levels or shells) • Protons are much larger and heavier than electrons and have the opposite charge, protons have a positive charge. They are located in the nucleus. The number of protons in the nucleus is called the atomic number. • Neutrons are large and heavy like protons, however neutrons have no electrical charge. They have the same mass as protons. • Protons and neutrons together account for the mass of the atom and their number. This is called the mass number of an atom • The number of electrons in an atom is always equal to the number of protons so that the atom is electrically neutral.

6. Atoms are held together by a force of chemical bonds. The two types of bonds are ionic and covalent. • In chemical bonds, atoms can either transfer or share their electrons to form a molecule. • Ionic bond: bond in which one or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract each other. • Because electrons have a negative charge atoms are no longer neutral when they gain or lose electrons. • The charged particles that result when atoms lose or gain electrons are called ions. • Cation: positively charged ion • Anions: negatively charged ion • Covalent bond: bond in which one or more pairs of electrons are shared by two atoms. • The ionic and covalent bonds just described hold atoms together within molecules. They are intramolecular bonds.

7. An ionic bond is an electrical attraction between two oppositely charged atoms or groups of atoms. It holds atoms together within molecules. • Normally atoms are neutral • When an atom loses or gains electrons (electrons are negatively charged), it is no longer neutral • The charged particles are called ions (electrically charged atoms or groups of atoms) • Loses 1 or more electrons becomes + charged = cations • Gains 1 or more electrons becomes – charged = anion

8. A covalent forms when 2 atoms share a pair of electrons. It holds atoms together within molecules. • Each atom donates half of the electrons to be shared • This sharing of electrons is a result of the electron attracting ability of the two bonded atoms

9. Do some examples on the board: ionic bonds hydroxide, bicarbonate, phos Do some examples on the board: covalent bonds, water, c dioxide, nito gas

10. Hydrogen Bond • Attraction between 2 molecules

11. A compound is formed when two or more different types of atoms chemically combine. • Water, salt and sugar are compounds • When elements are joined, the atoms lose their individual properties • They have different properties • Water is the most abundant compound in living organisms • Two-thirds of the weight of the adult human being • It is a physiologically important, because it is a good solvent, breaks down molecules by hydrolysis

12. Molecular formula is a shorthand way to indicate the type and number of atoms in a molecule. • Letter is the chemical symbol of the element • The subscript number shows the # of atoms. If no subscript it implies 1 atom

13. Structural formulasShows how atoms are arranged and joinedtogether in the molecule Chemical formula for aspirin

14. A chemical reactionis the process by which atoms or molecules interact to form new chemical combinations. • The atoms and molecules present before the chemical reaction occurs are called the reactants. • The new atoms and molecules that are created as a result of the reaction are called the products. • Chemical equations are an abbreviated method of showing the reactants and products in the chemical reaction.

15. Chemical equation: reactions between molecules Left side of equation is the reactants Right side of the equation is the products

16. Types of Chemical Reactions • Synthesis reactions: When 2 or more simple reactants combine to • Form a new, more complex product • Called synthesis, combination or composition reaction • A + B  AB • Is this anabolic for catabolic? DEHYDRATION SYNTHESIS: when 2 simple molecules combine to Form a more complex molecule by the removal of water Many reactions in the body are this type: glucose to glycogen exp

17. 2. Decomposition Reactions: When the bonds in a complex Reactant break to form new, simpler products. Are these catabolic or anabolic? AB  A + B HYDROLYSIS REACTION: When water is used to break the bonds Example is digestion

18. REACTION RATESChemical reactions occur at different rates.Forming of rust or tarnishing a silver are exp slowburning of paper or setting of epoxy are exp of fastsome are explosive like of dynamite going off. Influences of reaction rates are: Nature of reacting substance Substances Temperature Concentration Catalysts Surface area

19. Certain substances are more reactive than others depending on how readily bonds are broken and formed exp covalent and ionic bonds. • As temperature increases the speed of most chemical reactions also increases. The opposite is also true. If temp decreases, reaction rates decrease. • Within limits the greater the concentration of the reactions, the faster will be the speed of the reaction. • A catalyst is a substance that changes the rate of a reaction without itself being chemically altered in the process. Enzymes are catalysts. • Surface area: exp charcoal briquette vs coal dust, chewing up asa or antacids

20. Mixtures, solutions and suspensions • Mixture- a combo of 2 or more substances that can be separated by ordinary physical means. The substances retain their original properties after they have been combined in a mixture. • Solutions-mixtures in which the component molecules remain evenly distributed. Solutions are clear and they exist of 2 parts: • Solute: the substance that is present in the smaller amounts and that is being disolved • Solvent: is the component that is present in the larger amount and that does the dissolving

21. Water is the most common solventor the universal solvent If alcohol is used as the Solvent the solution is Called a tincture Exp. when iodine is Dissolved In alcohol.

22. Suspensions-settles unless continually shaken. If sand is mixed with water sand particles will settle at bottom. A suspension is cloudy and it’s particles settle. Blood cells form a suspension in plasma.

23. Electrolytes, Acids, Bases, and Buffers • Electrolytes are substances that breakup in a solution to form charged particles or ions. • These compounds are called electrolytes, because the ions can conduct an electrical current. • Electrolytes form cations and anions

24. The Na positively charged ion is attracted to the negatively charged oxygen End of the water molecule.

25. Acids-OJ, lemon juice, vinegar coffee, and aspirin all contain acids • Acids taste sour and defined as a proton donor • It gives away hydrogen ions (proton) in water • The strength of an acid depends on the degree to which it dissociates in water. • Hydrochloric acid (acid in the stomach) is a strong acid, because it dissociates readily to produce an abundance of hydrogen ions. • Carbonic acid is a weak acid, because most of the molecules remain intact in water and only a few dissociate into hydrogen ions and bicarbonate ions. • pH less than 7

26. BASES • Bases feel slippery and taste bitter • Examples are household ammonia, mom, and egg whites. • Defined as a proton acceptor BASES HAVE A PH GREATER THAN 7

27. THE pH SCALE IS USED TO INDICATE THE EXACT STRENGTH OF AN ACID OR A BASE. The greater # Hydrogen ions more acidic and the lower Is the pH Fewer hydrogen ions more basic solutions with higher pH number. Pure water has a pH of 7 Blood has a pH of 7.4, Is blood slightly acidic or alkalotic?

29. Neutralization reactions * The hydrogen ion from the acid reacts with the hydroxide ion from The base to form water * The acid removes or neutralizes the effect of the base and vice versa. The other product is salt *Salts are ionic compounds produced from neutralization reactions * Neutralization reactions help maintain the proper pH of blood

30. BUFFERS: a solution that resists changein pH when either an acid of base is added. Buffers are one of the homeostatic control mechanisms that maintain a normal pH In the Human body, acid-base balance is regulated by chemical buffer systems, the lungs and the kidneys.

31. The five major groups of organic compounds that are important to the human body are: carbohydrates, proteins, lipids, nucleic acids and adenosine triphosphate.

32. CARBOHYDRATES Carbs-important energy source in the body, it forms a reserve supply of stored energy. The simplest carbs are the monosaccharides or simple sugars: it is composed of 1 carbon atom, 2 hydrogen atoms and 1 oxygen atom CH2O The most important simple sugar is glucose It has 6 carbons atoms, 12 hydrogen atoms and 6 oxygen atoms C6H12O6 Because it has 6 carbons it is called a hexose Other simple sugars are fructose and galactose. Glucose requires no digestion therefore it can be given IV D 50 SEE PG 34 IN TEXT

33. Disaccharide: when 2 hexose monosaccharides are linked also called a double sugar3 common disaccharides1. Sucrose: table sugar2. Maltose: malt sugar3. Lactose: milk sugarPolysaccharides: long chains of monosaccharaides linked together 3 important polysaccharides1. starch: storage food in plants2. Cellulose: supporting tissue of plants (humans breakdown)3. glycogen: animal starch, storage form of carbs in the body

34. Proteins: all contain the elements:C, H, O and N • The building blocks of protein are amino acids. There is 20 total amino acids in the body, 11 can be man made, 9 must be eaten Proteins is the basic structural material of the body. FUNCTIONS OF PROTEINS 1. proteins can act as antibodies in the fight against disease 2. Muscles contain specific proteins that assist with contraction 3. Provide identification marks and receptor sites on cell membranes 4. They provide a source of energy • Hemoglobin-large protein molecule inside RBCs transports O2 to body tissues

35. Lipids: composed of CHO Characteristics: --Very similar to carbohydrates but have a lower oxygen content --Insoluble in water but are generally soluble in alcohol See table 2-6 pt 36 • Triglycerides: fats are most common, a concentrated source of energy, they provide protection, padding and insulation the components are glycerol and fatty acids ( see pt 36 in book for saturated and unsaturated fats) • Phospholipids: contain a phosphate group and nitrogen group, important in cell membranes in the body and are abundant in nerve and muscle cells. • Steroids: have 4 interconnected rings of carbon atoms, the most common steroid is cholesterol. Also included are the sec hormones and vitamin D

36. Nucleic Acids: C,H,O,N,P • The building blocks of nucleic acids are nucleotides • A nucleotide consists of a five carbon sugar, an organic nitrogenous base, and a phosphate group • Nucleotides are joined together by dehydration synthesis to form the nucleic acid

37. 2 types of Nucleic Acids • DNA: deoxyribonucleic acid: Genetic Material of the Cell • The sugar in the DNA is deoxyribose and 4 nitrogen bases are adenine, thymine • cytosine and guanine. The sequence of the nitrogen base is the genetic code. • 2. Two chains loosely joined together by H bonds and then twisted into a double helix

38. 2nd type RNA: ribonucleic acid Single Strand functions in the synthesis Of proteins with in the cell. Sugar is ribose Nitrogenous bases are: adenine, uracil, cytosine, and guanine. The DNA material gives the instructions For making proteins.

39. ADENOSINE TRIPHOSPHATEATP HIGH ENERGY COMPOUND COMPOSED OF ADENINE, RIBOSE AND 3 PHOSPHATE GROUPS. PHOSPHATE GROUP LINKED TOGETHER BY HIGH ENERGY BONDS THAT RELEASE CHEMICAL ENERGY WHEN BROKEN. THE CHEMICAL ENERGY IS USABLE BY THE CELLS OF THE BODY