Chapter 2 The Chemistry of Life. 2.1 The Nature of Matter I. Atom –smallest unit of matter A. Made of: 1. Proton  + charged, in nucleus 2. Electron 

Chapter 2 The Chemistry of Life

2.1 The Nature of Matter I. Atom –smallest unit of matter A. Made of: 1. Proton  + charged, in nucleus 2. Electron  - charged, outside nucleus (electron cloud) 3. Neutron  neutral, in nucleus B. Nucleus – positively charged center of atom

II. Element A. Pure substance made up of 1 type of atom B. Periodic table: chart with all the elements C. Periodic Box:  atomic # (# of protons)  chemical symbol  mass # III. Isotope : A. atoms of the same element with a different number of neutrons 1. To find the number of neutrons: mass # - atomic # = # of neutrons example: Carbon 12, Carbon 13, Carbon 14 (page 36) (nearest whole number; protons + neutrons)

6 electrons 6 protons 8 neutrons Isotopes of Carbon

IV. Compound A.2 or more elements chemically combined in definite proportions; New properties emerge; different from elements that make it Examples: H 2 O, NaCl, NaBr B. 2 Major Types of Chemical Bonds in Compounds : 1. Ionic a. transfer of electrons between atoms b. produces ions (+ and -)-example NaCl (Sodium Chloride) l l

Chemical Bonds Protons +17 Electrons - 17 Charge 0 Protons +11 Electrons - 11 Charge 0 Sodium atom (Na) Chlorine atom (Cl)

Transfer of electrons

2. Covalent a. sharing electrons between atoms b. electrons can be shared equally (nonpolar) or not equally (polar) - example H 2 O + + -

2.2 Properties of Water V. Properties: A. Polarity: uneven distribution of electrons between O and H atoms B. Hydrogen Bonds: weaker than ionic and covalent bonds, gives water many of its properties C. Cohesion: attraction of molecules of same substances (ex. water and water) D. Adhesion: attraction of molecules of different substances (ex. water and glass) 1. capillary action: tendency of water to rise in a thin tube due to adhesion E. All life processes need water to take place F. Helps transport materials (ex. blood)

VI. Mixture: 2 or more elements or compounds that are physically mixed but not chemically combined; retain their individual properties A. 2 types: 1. Suspension: small particles aren’t dissolved; still considered separate components-ex: blood (rbc, wbc, platelets, plasma) 2. Solution: components are evenly distributed throughout a. 2 parts: 1) solute: substance being dissolved 2) solvent: substance doing the dissolving example: sugar water sugar = solute and water = solvent

VII. pH Scale: A. measures H + ions in a solution B. Runs from 0-14 C. Each step (#) is a factor of 10

D. Acid: 1. Found on the ph scale from 0-6.9 2. Increase in strength as you get closer to zero 3. High concentration of H + (hydrogen ions) 4. Taste sour, can burn you 5. Examples: lemons, tomatoes, stomach acid, battery acid

E. Base: 1. Found on the pH scale from 7.1-14 2. Increase in strength as you get closer to 14 3. Low concentration of H + ions, high concentration of OH - ions (hydroxide ions) 4. Taste bitter, can irritate skin 5. Examples: antacid tablets, drano, soap, bleach F. Neutral 1. Found at 7 on the pH scale 2. Example: pure water

2.3 Carbon Compounds VIII. Carbon: A. Has four valence electrons allowing carbon to form MANY different bonds (single, double, or triple bonds) B. making 1000’s different compounds C. Compounds can be in a line, ring, or branched (page 44) IX. Macromolecules (page 45) A. monomers  polymers  macromolecules 0 0 00000000 Carbs, lipids, proteins, Nucleic acids

1. formed by process called polymerization: large compound formed by joining smaller ones together Page 45

X. Organic Compounds A. All contain Carbon B. Four groups in living things 1.Carbohydrates 2. Lipids 3. Nucleic acids 4. Proteins C. May be referred to as biomolecules or macromolecules

D. Carbohydrates 1. Made of: simple sugars (C, H, O atoms) 2. Types: a. Simple Carbohydrates : provide short term energy 1. Monosaccharides: one sugar molecule ex. glucose, fructose 2. Disaccharides: two sugar molecules ex. sucrose, lactose

b. Complex Carbohydrates: provides longer term energy 1. Polysaccharides: many sugar molecules; made up of glucose ex. starch, cellulose (fiber), glycogen 3. Function: mostly provides energy; some carbs structural like cellulose in plants Page 45

E. Lipids 1. Made of: fatty acids (ex: fats, oils, waxes -C & H atoms) 2. Types: a. Saturated: single bonds btw. Carbon atoms, solid at room temp. b. Unsaturated: double bond btw. Carbon atoms c. Polyunsaturated: many double bonds btw. Carbon atoms, liquid at room temp. 3. Function: insulation, stored energy, pheromones, cell membrane

F. Nucleic Acids 1. Made of: a. Nucleotides 1) 5-Carbon sugar 2) Phosphate Group 3) Nitrogen base Page 47

2. 2 Types: DNA and RNA 3. Function: store/transmit genetic information, contains code for all proteins

G. Proteins 1. Made of: amino acids 2. Types: 1000’s 3. Function: a. control cell processes b. Form bone, muscle, hair, nails c. Speeds up rates of reactions (enzymes) d.Transports substances (O 2 ) e. Immunity 4. Ex: Collagen, hemoglobin, insulin, antibodies

2.4 Chemical Reactions and Enzymes VI. Chemical Reactions: A. changes in chemical bonds that join atoms and compounds B. Parts of chemical equation: 1. Reactants (ex: substrates): Enter reaction 2. Products: Produced in reaction 3. Coefficient: # in front of substance used to balance equation b/c matter cannot be created or destroyed

C. Activation energy energy that is needed to get a reaction started 1. a factor in whether the overall chemical reaction releases energy or absorbs energy.

VII. Enzymes A. Biological catalyst (speeds up chemical reactions by lowering activation energy) B. Made up of protein – amino acids hooked together C. Function: 1. Speed up chemical reactions that would take place anyway ex: breathe out CO2 but would take 6 hours w/o enzyme 2. Makes materials for cell D. Affected by: 1.Temperature- if too hot or too cold, protein will not work 2.pH- if too high or too low, protein will not work 3. Concentration- smaller amount = slower reaction rate

Enzymes Con’t E. Lowers activation energy 1. allows reaction to occur more easily

Enzymes Con’t 2. HOW? a. Provides active site where reactants (aka. substrate) can join together called  enzyme-substrate complex- lock and key mechanism b. E-S Complex remains together until the reaction is done (products are released) c. The enzyme is not permanently changed or used up and can be used again for the same reaction (very specific).

An Enzyme-Catalyzed ReactionPage 52

2-1 1. The particles that move around the nucleus of an atom are called A. neutrons. B. protons. C. electrons. D. isotopes.

2-1 2. The atomic number of a carbon atom is 6. How many neutrons does the isotope carbon-14 have? A. 6 B. 8 C. 12 D. 14

2-1 3. Which of the following statements about the three isotopes of carbon is true? A. They are all radioactive. B. They have different numbers of electrons. C. They have the same chemical properties but differ in atomic mass. D. They have the same number of protons and neutrons.

2-1 4. A chemical compound consists of A. electrons mixed with neutrons. B. two or more elements combined in a definite proportion. C. two or more elements combined in any proportion. D. at least three elements combined by ionic or covalent bonds.

2-1 5. Van der Waals forces are the result of A. unequal sharing of electrons. B. ionic bonds. C. the bonding of different isotopes. D. the chemical combination of sodium and chlorine.

2-2 6. A molecule in which the charges are unevenly distributed is called a A. polar molecule. B. cohesive molecule. C. hydrogen molecule. D. covalent molecule.

2-2 7. A dissolved substance is called a A. solvent. B. solution. C. solute. D. suspension.

2-2 8. A compound that produces hydroxide ions in solution is called a(an) A. base. B. buffer. C. acid. D. salt.

2-2 9. Hydrogen bonds between water molecules result from A. adhesion between water molecules. B. magnetic attractions between water molecules. C. uneven electron distribution in each water molecule. D. ionic bonds in the water molecule.

2-2 10. On a pH scale, a value of 2 means that the solution has A. equal concentrations of H + and OH - ions. B. the same concentration of H + ions as pure water. C. higher concentration of H + than in pure water. D. lower concentration of H + than in pure water.

2–3 11. Large carbohydrate molecules such as starch are known as A. lipids. B. monosaccharides. C. proteins. D. polysaccharides.

2–3 12. Many lipids are formed from glycerol and A. fatty acids. B. monosaccharides. C. amino acids. D. nucleic acids.

2–3 13. Proteins are among the most diverse macromolecules because A. they contain both amino groups and carboxyl groups. B. they can twist and fold into many different and complex structures. C. they contain nitrogen as well as carbon, hydrogen, and oxygen. D. their R groups can be either acidic or basic.

2–3 14. Which of the following statements about cellulose is true? A. Animals make it and use it to store energy. B. Plants make it and use it to store energy. C. Animals make it and use it as part of the skeleton. D. Plants make it and use it to give structural support to cells.

2–3 15. A major difference between polysaccharides and proteins is that A. plants make polysaccharides, while animals make proteins. B. proteins are made of monomers, while polysaccharides are not. C. polysaccharides are made of monosaccharides, while proteins are made of amino acids. D. proteins carry genetic information, while polysaccharides do not.

2–4 16. The elements or compounds produced by a chemical reaction are known as A. reactants. B. enzymes. C. products. D. waste.

2–4 17. Chemical reactions always involve A. changes in energy. B. enzymes. C. catalysts. D. changes in the atomic number of the reactants.

2–4 18. The factor that prevents many energy- releasing reactions from occurring at relatively low temperatures is called A. catalytic energy. B. chemical bond energy. C. enzyme energy. D. activation energy.

2–4 19. Which of the following statements is true? A. All proteins are enzymes. B. All catalysts are enzymes. C. All enzymes are catalysts. D. All catalysts are proteins.

2–4 20. What happens to an enzyme after the reaction it catalyzes has taken place? A. The enzyme is destroyed, and the cell must make another. B. The enzyme holds on to the product until another enzyme removes it. C. The enzyme is unchanged and ready to accept substrate molecules. D. The enzyme changes shape so it can accept a different kind of substrate.