Chapter 6

1. Chapter 6 Chemistry in Biology

2. 6.1: Atoms, Elements and Compounds • Matter is composed of tiny particles called atoms. • Building ____________ of matter = ____________ • Composed of 3 ____________ particles: protons, ___________, and electrons • Protons = __________ charge • Neutrons = no charge (_____________) • Electrons = ___________ charge • Protons and ____________ are in the nucleus blocks atoms subatomic neutrons positive neutral negative neutrons

3. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds • Electrons are negatively charged particles that are located outside the nucleus.

4. Atomic Structure • Electrons are moving around ____________ in various energy _____________ • Structure of the ____________ is possible because of the ____________ of protons and ______________ • Atoms have no __________ charge because the number of ___________ equals the number of _____________ nucleus levels atom attraction electrons overall protons electrons

5. Element • Element – pure substance that ___________ be broken down into other substances by either ____________ or physical means • Made up of _______ type of atom • _____ elements have been discovered; _________ occur naturally in nature; approx. _______ are found in living organisms cannot chemical one 112 92 20

6. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds The Periodic Table of Elements • Horizontal rows are called periods. • Vertical columns are called groups.

7. Periodic Table of Elements • Periodic Table of Elements - _____________ table of the elements • Horizontal rows = __________ • Vertical ___________ = groups • Elements in the same _______ have similar physical and __________ properties organized periods columns group chemical

8. Isotopes • Isotopes – atoms of the __________ element with the same number of ____________ and electrons but a different number of _______ • Mass _____________ identifies an isotope • Mass number = _____________ + ______________ • Ex. C-12 ____p ____n ____e C-13 ____p ____n ____e C-14 ____p ____n ____e same protons neutrons number protons neutrons 6 6 6 6 7 6 6 8 6

9. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds Isotopes • Atoms of the same element that have the same number of protons and electrons but have a different number of neutrons

10. Isotopes (Cont.) • Some isotopes are unstable because of the ______________ in neutrons and the nucleus begins to decay or ______________ giving off radiation - _________________ • Many applications such as ________________ dating and treating _____________ difference breakdown radioisotopes radioactive cancer

11. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds Radioactive Isotopes • When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications.

12. Compounds • Compounds – pure substance formed from the _________________ of 2 or more different ______________ • NaCl or H2O – chemical _____________ - tells you the _____ of elements involved and the _____________ of atoms of each element • Characteristics: • Always formed from _____________ combinations of elements in a ____________ ratio • Cannot be broken down by ____________ means but can be broken down into _____________ elements by chemical means combination elements formula kinds number specific fixed physical original

13. Chemical Bonds • Chemical bonds – force that holds _________ together • Electrons are _______________ directly in forming chemical _________ • 1st energy _________ holds up to ______ electrons • 2nd energy _________ holds up to ______ electrons • 3rd energy _________ holds up to ______ electrons • 4th energy _________ holds up to ______ electrons • Electrons in the ______________ energy level or _________ are involved in bonding atoms involved bonds level 2 level 8 level 8 level 16 outermost valence

14. Chemical Bonds (Cont.) • An empty or _______ energy level is more stable than a _____ filled energy level so atoms will ________ to lose or gain electrons to _________ stability • Covalent bonds – electrons are __________ • H2O • Molecule – compound in which the ___________ are held together by ____________ bonds • Atoms can share 1, ____ or 3 pairs of electrons to form ___________, double or triple bonds full partially seek achieve shared atoms covalent 2 single

15. Chemistry in Biology • A molecule is a compound in which the atoms are held together by covalent bonds. Chapter 6 6.1 Atoms, Elements, and Compounds Chemical Bonds • Covalent bonds bond that forms when electrons are shared

16. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds Ionic Bonds • Electrical attraction between two oppositely charged atoms or groups of atoms

17. Chemical Bonds (Cont.) • Ionic bonds – formed between 2 _____________ charged atoms or _______ of atoms called ions • Ions are ____________ when electrons are donated or ____________ either filling up an energy level or emptying one • Ions carry a ____________ • _________ ions are attracted to negative ________ forming ionic bonds • Ex. NaCl oppositely groups formed accepted charge Positive ions

18. Chemical Bonds (Cont.) • Characteristics of ____________ compounds • Tend to dissolve in ____________ • ____________ at room temperature • Higher _____________ points • Ions are important in the maintenance of ____________; nerve ______________ and muscle contractions ionic water crystalline melting homeostasis impulses

19. van der Waals Forces • van der Waals forces – attraction between _______________ caused by areas of __________ charge • Atoms shared in a ____________ bond are not always shared ___________ and the unequal distribution of the _________ cloud around a molecule create theses _______ of unequal charge • Relatively ___________ but depend on size of ___________, its shape and ability to ___________ electrons • Responsible for the ability of the __________ to cling to smooth surfaces and water’s ability to form ______________ molecules unequal covalent equally electron areas weak molecule attract gecko droplets

20. 6.2 Chemical Reactions • Chemical reactions allow living things to grow, develop, reproduce and adapt. • Chemical reaction – process by which ___________ or groups of atoms in substances are ______________ into different substances • Bonds are _____________, atoms ______________ and new bonds formed atoms reorganized broken rearranged

21. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • Glucose and oxygen react to form carbon dioxide and water.

22. Physical vs. Chemical Change • Physical change – ice melting; no _____________ reaction involved • Chemical change – one ___________ turning into another substance through a chemical reaction; metal _____________ chemical substance rusting

23. Chemical Equations • Chemical equations • Reactants -> Products; arrow reads ____________ • C6H12O6 + O2 -> CO2 + H2O • C6H12O6 + _____O2 -> _____CO2 + _____H2O - balanced • Matter cannot be ____________ or destroyed so the number of atoms of each ___________ in the reactant(s) must _________ the number of atoms of each element in the ____________________ yields 6 6 6 created element equal products

24. Energy of Reaction • Energy is the ______ to starting a chemical reaction • Activation energy – minimum ____________ of energy needed for reactants to form ____________ in a chemical reaction • Varies for each _________________ • Reactions will either _________ off energy or ________ energy key amount product reaction give absorb

25. Chemistry in Biology Chapter 6 6.2 Chemical Reactions Energy of Reactions • Theactivation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction.

26. Energy of the Reaction (cont.) • Exergonic reaction - ______________ in which the products have less energy than the ____________ • Energy is _________ off reaction reactants given

27. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • This reaction is exothermic and released heat energy. • The energy of the product is lower than the energy of the reactants.

28. Energy of the Reaction (Cont.) • Endergonic reaction – reaction in which the ____________ have more energy than the _______________ • Energy is ____________ products reactants absorbed

29. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • This reaction is endothermic and absorbed heat energy. • The energy of the products is higher than the energy of the reactants.

30. Enzymes • Enzymes – special ____________ that are biological catalysts that work to ________ up the rate of chemical reactions • Catalyst – substance that _______________ the activation energy needed to ________ a chemical reaction • Not _______________ up in the reaction; ________________ • Necessary because chemical _______________ tend to occur too slowly because the _____________ energy is high • Specific to ________ reaction proteins speed lowers start used reusable reactions activation one

31. Chemistry in Biology • It does not increase how much product is made and it does not get used up in the reaction. Chapter 6 6.2 Chemical Reactions Enzymes • A catalyst is a substance that lowers the activation energy needed to start a chemical reaction. • Enzymes are biological catalysts.

32. Enzymes (Cont.) • End in _____; name describes what it does • Ex. Amylase – speeds up the _____________ of amylose • Reactants that bind to the _______________ are called _____________ • _____________ of substrates depends on the number of _____________ • Specific location where the ____________ binds on an enzyme is called the __________ site -ase breakdown enzyme substrate Number reactants substrate active

33. Enzymes (Cont.) • Active site and ____________ have complementary shapes so that only the required _____________ can activate the appropriate enzyme • Once the __________________ binds to the active site the active ________ changes shape and forms the __________________________ complex which helps chemical bonds to be broken and _______ bonds to form and then the ______________ releases the products • Changes in temperature, ________ and other factors can increase or _________________ enzyme activity • Enzymes are essential to ____________ substrate substrate substrate(s) site enzyme-substrate new enzyme pH decrease life

34. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • The reactants that bind to the enzyme are called substrates. • The specific location where a substrate binds on an enzyme is called the active site.

35. 6.3 Water and Solutions • The properties of water make it well-suited to help maintain homeostasis in an organism.

36. Polarity • Water is a ___________ molecule • Polar molecule – molecule that has an ______________ distribution of charges because electrons are shared _________________ • Polarity is the property of having _____ opposite poles or _______; Ex. Magnet • Opposite ends of ___________ molecules are attracted to each other • In _________ this is called ___________ bonding – weak interactions involving a _____ atom and an atom of F, ____, or N polar unequal unequally 2 ends polar water hydrogen H O

37. Chemistry in Biology Chapter 6 6.3 Water and Solutions Enzyme-Controlled Reactions

38. Properties of Water (Fig. 6.20, pg. 162) • 1. Liquid water becomes ______ dense as it cools • Begins at 4°C and is completed by _______ • Water __________ when it freezes • Ice floats in liquid ______________ • 2. Water is ____________ - it sticks to other _____________ by forming hydrogen bonds • Makes ______________ action possible • Ex. Explains a plant’s ability to move _________ up the stems against ____________ less 0°C expands water adhesive substances capillary water gravity

39. Properties of Water (Cont.) • 3. Water is cohesive – it ___________ to itself by hydrogen bonds • Creates ____________ tension • 4. Water forms _____________ • Mixtures – combination of ____ or more substances in which each substance retains its individual ___________________ and properties • Homogeneous mixture – mixture with a ____________ composition • Also called a ___________; has ____ parts • Ex. Salt water • Solvent – substance in which another ____________ is dissolved; Ex. __________ • Solute – substance that is ______________ in the solvent: Ex. ___________ sticks surface mixtures 2 characteristics uniform solution 2 substance water dissolved salt

40. Properties of Water (Cont.) • Heterogeneous mixture – mixture in which the ____________ remain distinct • Suspension – mixture of ___________ and nondissolved ________________; particles will ___________ to the bottom; Ex. Sand and water • Colloid – mixture in which the ___________ do not settle out; Ex. ________ components water solutes settle components blood

41. 5. Acids and Bases • Because of water’s ___________ solutes readily dissolve in _________ creating a variety of solutions • When a substance containing H is ______________ in water the substance might release _____ ions (H+) because of the strong ________________ to the negatively charged ___________ atoms in water molecules • Acids – substances that release H+ ions when _____________ in water • More _______ released the more _________ the solution polarity water dissolved H attraction oxygen dissolved H+ acidic

42. Chemistry in Biology Chapter 6 6.3 Water and Solutions Acids and Bases • Substances that release hydrogen ions (H+) when dissolved in water are called acids. • Substances that release hydroxide ions (OH–) when dissolved in water are called bases.

43. Acids and Bases (Cont.) • Bases – substances that _____________ hydroxide ions (OH-) when dissolved in water • More OH- released the more _________ the solution • pH is a measure of the ______________ of H+ in a solution • Buffers are _____________ that can react with acids or ___________ to maintain pH within _______________ ranges; very important to living organisms who cannot ______________ large changes in pH • Ex. Blood pH is maintained between _____ and ______ release basic concentration substances bases acceptable tolerate 7.0 7.4

44. Chemistry in Biology Chapter 6 6.3 Water and Solutions pH and Buffers • The measure of concentration of H+ in a solution is called pH. • Acidic solutions have pH values lower than 7. • Basic solutions have pH values higher than 7.

45. Chemistry in Biology Chapter 6 6.3 Water and Solutions • Buffers are mixtures that can react with acids or bases to keep the pH within a particular range.

46. 6.4 The Building Blocks of Life • Organisms are made up of carbon-based molecules • Carbon-containing compounds are ____________ compounds organic

47. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life Organic Chemistry • The element carbon is a component of almost all biological molecules.

48. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life • Carbon has four electrons in its outermost energy level. • One carbon atom can form four covalent bonds with other atoms. • Carbon compounds can be in the shape of straight chains, branched chains, and rings.

49. Why is C so important to life? • C has ______ valence electrons and can form _______ covalent bonds forming molecules with __________ chains, branched chains and ________ • C atoms can be joined together to form ____________ molecules called macromolecules • Macromolecules are _______________ - large molecules made from ______________ units of identical or nearly _________ compounds called ________________ that are linked together by a series of _______________ bonds 4 4 rings straight large polymers repeating identical monomers covalent

50. 4 Major Organic Compounds/Macromolecules • (Table 6.1, pg. 167)1. Carbohydrates – compounds that contain C, ____ and O in a ratio of 1:2:1; usually occur in ___________ • Have the formula (CH2O)n where n ranges from _____ to ______ forming simple sugars or _____________________ • Ex. Glucose • Function – energy __________ • 2 monosaccharides joined together form a _______________ • Ex. Sucrose and ___________ • Function - ___________ source • Longer ______________ molecules are called polysaccharides • Ex. Glycogen, _____________ and starch • Function – energy storage and _____________ support H rings 3 7 monosaccharides source disaccharide lactose energy carbohydrate cellulose structural