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Unit 2 Chemical Basis for Life. Chapter 6 Chemistry in Biology.

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Presentation on theme: "Unit 2 Chemical Basis for Life. Chapter 6 Chemistry in Biology."— Presentation transcript:

1 Unit 2 Chemical Basis for Life

2 Chapter 6 Chemistry in Biology

3 Section 1: Atoms, Elements, & Compounds (p. 148-155) Section 2: Chemical Reactions (p. 156-160) Section 3: Water & Solutions (p. 161-165) Section 4: The Building Blocks of Life (p. 166-171)

4 Section 1 Atoms, Elements, and Compounds

5 Objectives  Living things consist of atoms of different elements  Ions form when atoms gain or lose electrons  Atoms share pairs of electrons in covalent bonds

6 The atom  The atom is the smallest basic unit of matter  Atoms are very small

7 The atom  There are three parts of a an atom Subatomic particle ChargeLocation ProtonPositiveNucleus NeutronNeutralNucleus ElectronNegativeSurrounding nucleus

8 Elements  An element is one particular type of atom, and it cannot be broken down into a simpler substance by ordinary chemical means  Gold  Aluminum  Helium

9  Atoms & Elements Atoms & Elements

10 Key Elements  In biology, there are SIX very important elements  Carbon  Hydrogen  Oxygen  Phosphorus  Sulfur  Nitrogen CHOPSN

11 How are elements different  The number of protons determines the identity of an element  Carbon: 6 protons  Oxygen: 8 protons  The number of electrons determines the property of an element  Carbon: 6 electrons, 4 on OUTSIDE  Oxygen: 8 electrons, 6 on OUTSIDE

12 Carbon diagrams

13 Chemical Party https://www.youtube.com/watch?v=wBCmt_pJTRA

14 Lonely Atoms  Atoms rarely are found alone in nature  They will do ANYTHING to get to 8 electrons on the outside  Steal  Dump  Share

15 Compounds  A compound is a substance made of atoms of different elements bonded together  Result of sharing, stealing, or dumping electrons  Atoms bonded in a specific ratio

16 Carbon Compounds (more about this later)  Carbon can form many various bonds to form  Carbohydrates  Proteins  Nucleic acids  Lipids

17 Ionic Bond  Ionic bonds are formed through the electrical force between oppositely charged ions  Opposites attract!  Ex: Salt aka sodium chloride (NaCl)  Positive sodium (Na + )  Negative chloride (Cl - )

18 NaCl – ionic bond

19 Ions  Ions are atoms that have gained or lost one or more electrons.  Results in a change in electrical charge  Gain e - becomes negative  Lose e - becomes positive

20 Ions, cont.  Very important to organisms  Hydrogen ions (H + ) needed to produce chemical energy in cells  Calcium ions (Ca 2+ ) needed for all muscle movement in your body  Chloride ions (Cl - ) needed for many chemical signals in the brain

21 Covalent Bond  Not all atoms easily gain or lose their electrons!  Some atoms share their electrons instead!  Covalent Bond: forms when atoms share a pair of electrons  Usually a very strong bond  Atoms may have several covalent bonds to share several electrons

22 H 2 O – covalent bond

23 CO 2 – covalent bond

24 Covalent Bond, cont.  Molecule: two or more atoms held together by covalent bonds  Ex: carbon dioxide (CO 2 )  Carbon atoms needs 4 electrons to fill outer level, oxygen needs two  Carbon shares with 2 oxygen!

25  Ions, Ionic Bonds, & Covalent Bonds Ions, Ionic Bonds, & Covalent Bonds

26

27 Review  What are atoms?  How are the particles that make up atoms diagrammed?  What are the similarities between covalent and ionic bonds?

28 Section 2 Chemical Reactions

29 Objectives  Bonds break and form during chemical reactions.  Chemical reactions release or absorb energy.

30 Evidence of a chemical reaction Temperature change Formation of a solid (precipitate) Color change (sometimes) Odor (sometimes) Formation of gas

31 Chemical Reaction... Gummy bear torture

32  Bonds break & form during chemical reactions  Plant/Animal cells break down sugars to get usable energy  Cells build protein molecules by bonding amino acids together  Chemical reactions change substances into different substances by breaking and forming chemical bonds

33  Reactants are the substance changed during a chemical reactions  Oxygen (O 2 ) & Glucose (C 6 H 12 O 6 )  Products are the substances made by a chemical reaction  Carbon Dioxide (CO 2 ) & Water (H 2 O) 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O

34 Reactants & Products

35  Energy is needed to break bonds in molecules  Bond energy is the amount of energy that will break a bond between two atoms.  Every atom has different bond energy A SPECIFIC amount of energy is needed to break bonds in an oxygen molecule A SPECIFIC amount of energy is needed to break bonds in a glucose molecule  Energy is released when bonds are formed  The amount of energy released is equal to the energy that breaks the same bond Energy needed to break apart water molecule = energy released when hydrogen & oxygen atoms bond to form a water molecule

36  All chemical reactions involve changes in energy  Energy added to the reactants breaks their chemical bonds  When new bonds form in the products, energy is released  Energy is both absorbed and released during a chemical reaction!  Some release more energy than they absorb (Generous)  Some absorb more energy than they release (Greedy)

37  Generous chemical RXNs that release more energy than they absorb  = Exothermic reaction  Excess energy is the difference in bond energy between the reactants and products  Excess energy is often released as heat or light Cellular respiration releases usable energy for your cells & heat!

38  Greedy chemical RXNs that absorb more energy than they release  = Endothermic reaction In photosynthesis, plants absorb energy from sunlight and use that to make sugars and carbohydrates

39 Exothermic VS. Endothermic graphs

40 But how does a rxn start?  Some energy must first be absorbed by the reactants in ANY chemical reaction  The amount of energy needed will vary  Activation energy is the amount of energy that needs to be absorbed for a chemical reaction to start  Push a rock up a hill

41 Activation energy  Activation Energy Activation Energy

42 Catalysts & Enzymes  A catalyst is a substance that lowers the activation energy needed to start a chemical reaction.  Special proteins called enzymes are the biological catalysts that speed up the rate of chemical reactions in biological processes.

43 Enzymes  https://www.youtube.com/watch?v=XTUm-75-PL4 https://www.youtube.com/watch?v=XTUm-75-PL4

44 Review  What are the parts of a chemical reaction?  How can energy changes be related to chemical reactions?  What is the importance of enzymes in living organisms?

45 Section 3 Water and Solutions

46 Objectives  Life depends on hydrogen bonds in water.  Many compounds dissolve in water.  Some compounds form acids or bases.

47 Organisms’ bodies, (their _____________), are made up of mostly ____________________ The water in cells gives the cell _______________ and ___________________ materials within organisms. All of the processes necessary for an organism’s life take place within the ______________________________ of the cell CELLS WATER STRUCTURE TRANSPORTS WATERY ENVIRONMENT

48 1.______________________ 2. ______________________ 3. ______________________ 1.HIGH SPECIFIC HEAT 2. COHESION 3. ADHESION

49 Hydrogen Bonding

50 Negative Charge Positive Charge Water is a “______________” molecule Form when atoms in a molecule have ____________ pulls on the _____________ they share. Opposite charges of polar molecules can interact to form ____________________ bonds. An attraction between a slightly _______________ hydrogen atom and a slightly ______________ atom. (Usually _______________________________) Hydrogen bonds are part of the structures of _______________ and of ______________ Shared Electrons POLAR UNEQUAL ELECTRONS HYDROGEN POSITIVE NEGATIVE OXYGEN OR NITROGEN PROTEINS DNA

51 Cohesion : the attraction among __________________ of the same substance. Cohesion from hydrogen bonds makes water molecules _____________________. Cohesion produces __________________, ( “skin on water” ) MOLECULES STICK TOGETHER SURFACE TENSION

52 Adhesion : the attraction among __________________ of ______________ substances. For example, water molecules stick to other things. Water in a test tube, (water is attracted to the ____________) MOLECULES DIFFERENT GLASS

53 Materials such as ________________ and ____________ cannot be transported form one part of an organism to another unless they are dissolved in blood, plant sap, or other water based fluids. ______________: Mixture of a substance that is the same throughout. ___________: Substance that is present in the greater amount and dissolves another substance. ___________: Substance that dissolves in a solvent. SUGARS OXYGEN SOLUTION SOLVENT SOLUTE

54 Mixtures Heterogeneous  A mixture with easily separated parts with their distinct properties Homogeneous  A mixture that it the SAME throughout and hard to tell individual characteristics

55 Some compounds form ______________ or _____________ because they _______________ into _______________ when they dissolve in ___________. BASE : Compounds that remove H+ ions from a solution ACID: Compounds that release a proton - a hydrogen ion(H+) – when it dissolves in water ACIDS BASES BREAK UP IONS WATER

56 More acidic More basic neutral

57 pH Scale examples

58 Review  How does the structure of water make it a good solvent?  What are the similarities and differences between solutions and suspensions?  What are the differences between acids and bases?

59 Section 4 The Building Blocks of Life

60 Objectives  Carbon atoms have unique bonding properties.  Four main types of carbon-based molecules are found in living things.

61 ____________________ PROTEIN LIPIDS CARBOHYDRATES ATP NUCLEIC ACID

62  Carbohydrates are molecules composed of carbon, hydrogen, and oxygen  Include sugars & starches  Can be broken down to provide useable energy for cells  Major part of plant cell structure  The most basic carbs are simple sugars, monosaccharides  Polysaccharides are polymers of monosaccharides

63 USED BY CELLS FOR __________ ___________ AND __________ ____________. SIMPLE CARBS = _______________________________ COMPLEX CARBS = _____________________________ _____________________________ ENERGY SOURCE ENERGY STORAGE ONE OR TWO SUGAR MOLECULES LONG CHAINS OF SUGAR MOLECULES Ex) Starches such as potato, pasta, bread ________________________________

64  Proteins are the most varied of the carbon-based molecules in organisms  Have a role in movement, eyesight, digestion, etc.  A protein is a polymer made of monomers called amino acids  Amino acids are molecules that contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur  Organisms use 20 different amino acids to build proteins  The body makes 12 of the 20, the other 8 come from food

65

66 MAKE UP _________________. INVOLVED IN ALL _______ ____________. BUILDING BLOCKS = _________ __________. _________________= TYPE OF PROTEIN THAT STARTS AND SPEEDS UP CHEMICAL REACTIONS IN CELLS. CELLS LIFE PROCESSES AMINO ACIDS ENZYME

67  Lipids are nonpolar molecules that include fats, oils, and cholesterol  Contain chains of carbon bonded to oxygen & hydrogen  Some broken down for useable energy  Others are part of a cell’s structure  Fatty acids are chains of carbon atoms bonded to hydrogen atoms.  Saturated fatty acids have single carbon-carbon bonds  Unsaturated fatty acids have double carbon- carbon bonds

68

69 DON’T MIX WITH ______________. PHOSPHOLIPIDS – MAKE UP ________ ______________. FATS AND OILS THAT _________ ___________. ORGANISMS USE FATS AND OILS WHEN THEY HAVE USED UP ___________________. _________- SOLID AT ROOM TEMPERATURE. _________- LIQUID AT ROOM TEMPERATURE. WATER CELL MEMBRANE STORE ENERGY CARBOHYDRATES FATS OILS

70 MAJOR ___________ ___________ MOLECULE IN CELL. ENERGY IN __________________ AND __________ AND _____________________ MUST BE TRANSFERRED TO ATP IN CELL TO BE USED. ENERGY CARRYING CARBOHYDRATES LIPIDS PROTEINS

71  Detailed instructions to build proteins are stored in extremely long carbon-based molecules called nucleic acids  Nucleic acids are polymers that are made up of monomers called nucleotides  Nucleic acids differ from the other carbon- based molecules  The others have a large # of functions  Nucleic acids have just 1 function… make proteins DNA stores info for putting amino acids together to make proteins RNA helps to build proteins

72 HAVE ALL INFO NEEDED TO MAKE __________. “_______________” OF LIFE. BUILDING BLOCKS OF _____________. TWO TYPES: ________ AND _______. PROTEIN BLUE PRINT NUCLEOTIDES DNA RNA

73  Each subunit of a complete carbon- based molecule is called a monomer  A polymer is a large molecule, or macromolecule, made of many monomers bonded together  Monomers of a polymer may be the same (ex. Starches)  Or different (proteins)

74 COMPOUNDBUILDING BLOCK (POLYMER)(MONOMER) PROTEIN AMINO ACID LIPID (FAT)FATTY ACID CARBOHYDRATESUGARS NUCLEIC ACIDSNUCLEOTIDE

75 Review  What is the role of carbon in living organisms?  What are the four major families of biological macromolecules?  What are the functions of each group of biological macromolecules?


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