1. The Chemistry of Life

2. Things you should be able to do…
Describe how the unique properties of water support life on Earth.
Explain how carbon is uniquely suited to form biological macromolecules.
Describe how biological macromolecules form from monomers.
Compare the structure and function of carbohydrates, lipids, proteins and nucleic acids in organisms.
Describe the role of an enzyme as a catalyst in regulating a specific biochemical reaction.
Explain how factors such as pH, temperature and concentration levels can affect enzyme function.

3. Vocabulary
acid
base
buffer
monomer
polymer
carbohydrate
monosaccharide
lipid
nucleic acid
nucleotide
protein
amino acid
chemical reaction
reactant
product
activation energy
catalyst
enzyme
substrate
atom nucleus electron element isotope compound ionic bond ion covalent bond molecule
Van der Waals forces
Hydrogen bond
Cohesion
Adhesion
Mixture
Solution
Solute
Solvent
Suspension
pH scale

4. The atom Basic Chemistry basic unit of matter
Composed of protons, neutrons and electrons
Electrons are involved in the interactions between atoms

5. Compound Basic Chemistry
a substance formed by the chemical combination of two or more atoms in definite proportions
Chemical formulas tell us the types of atoms and the proportion of atoms in a compound
EX: H2O, C3H8, C6H12O6

6. Chemical bonds Basic Chemistry Hold atoms in a compound together
Different types of chemical bonds include
Ionic bonds = weaker bonds result from a transfer of electrons from one atom to another
Covalent bonds = very strong bonds that result when two or more atoms share electrons
Van der Waals forces = forces of attraction between molecules

7. Chemical Reactions Basic Chemistry
Result when bonds between atoms are broken and rearranged to form new substances

8. Organic vs Inorganic compounds
Basic Chemistry
Organic vs Inorganic compounds
Organic compounds = composed of carbon AND hydrogen
EX: proteins, lipids, carbohydrates, DNA, RNA
Inorganic compounds = not composed of BOTH carbon and hydrogen
Ex: H2O, CO2

11. Molecular Structure Structure of Water
H2O = 2 atoms of hydrogen and 1 atom of oxygen
Covalent bonds between atoms = electrons are shared

12. Water is Polar Structure of Water
Uneven sharing of electrons between oxygen and hydrogens
Oxygen becomes slightly negative
Hydrogens become slightly positive

13. Click here for animation
Structure of Water
Hydrogen bonds
Van der Waal forces
Form between water molecules
Negative oxygen of one water molecule and the positive hydrogen of another water molecule
Explain ALL other properties of water
Cohesion, adhesion, high heat capacity, density
Click here for animation

14. DRAW THIS IN YOUR NOTES TO SHOW HYDROGEN BONDING BETWEEN MOLECULES
The opposite partial charges of the hydrogen and oxygen atoms attract each other, and so these regions will likely be found together between water molecules
DRAW THIS IN YOUR NOTES TO SHOW HYDROGEN BONDING BETWEEN MOLECULES

15. EXPLAIN WHY TWO WATER MOLECULES WOULD NOT ALIGN AS SHOWN IN THIS DIAGRAM
The partial positives of the hydrogen atoms repel each other, making it unlikely that water molecules will be arranged in this way.

16. 1. Cohesion Properties of Water tendency of water to stick to itself
causes surface tension
More force is required to break the surface of a liquid

17. 2. Adhesion Properties of Water
tendency of water to stick to other substances

18. 3. Water and Heat Energy Properties of Water
Water has a high capacity to absorb and retain heat (specific heat)
Water requires more heat energy to change temperature
Even if the air temperature changes drastically, water will resist the change
Water in the body helps maintain body temperature
Water on earth helps regulate temperature

19. 4. Density Properties of Water Density = mass per unit volume
Water has a greater density as a liquid than a solid
Frozen water floats on the surface of ponds and other bodies of water leaving denser liquid water beneath

20. When leafy green vegetables are frozen and then thawed, their texture changes. Can you explain why freezing causes this change?
Plant cells contain a high percentage of water, particularly in the central vacuole. When frozen, the density of water decreases and the ice takes up a larger volume insides the cell. This causes the cell wall to burst and results in leafy vegetables losing their crunch.

21. 5. Water is the Universal Solvent
Properties of Water
5. Water is the Universal Solvent
Solvent = substance which dissolves other substances
“Like dissolves like”
Water dissolves ionic substances and polar molecules
Salt is polar and therefore dissolves in water
Lipids are nonpolar and therefore don’t dissolve in water

23. Background Acids, Bases and pH
Water sometimes splits apart to form ions
Water is neutral because [OH-] = [H+]

24. pH scale Acids, Bases and pH Ranges from 0 to 14
Measure of the concentration of hydrogen ions
Concentration of H+ ions determines whether solutions are acidic or basic
Pure water has a pH of 7 = NEUTRAL
Optimal pH of blood = 7.3
Each step on the pH scale represents a factor of 10

25. Defined Acids, Bases and pH Acids Bases form H+ in solution
have high H+ concentration
have pH less than 7
Bases
Form OH- in solution
have low H+ concentration
have pH greater than 7

26. Buffers Acids, Bases and pH Control pH in most living things
Prevent sharp changes in pH
Important in maintaining homeostasis
Changes in pH can unfold enzymes, making them useless in carrying out chemical reactions

27. Quick Lab Determining pH of household items
Predict whether the household samples provided are acidic or basic
Test pH of each item with different indicator papers
Construct a pH scale (1-14) and write each item you tested in the appropriate place on the pH scale

30. Organic compounds Chemistry of Carbon
Organic compounds contain carbon atoms bonded to hydrogen atoms
All life on earth is carbon-based
Covalent bonds between atoms = electrons shared
can be single, double or triple

31. Unique Properties of Carbon
Chemistry of Carbon
Unique Properties of Carbon
Carbon can form 4 bonds
Carbon can bond with other elements (H, O, N, P,)
Carbon can bond with itself
Can form chains unlimited in length
Carbon chains can be branched or form rings

32. C C C Unique Properties of Carbon Chemistry of Carbon
How many hydrogen atoms are needed to make up one molecule of the compound
C C C

33. C C C Unique Properties of Carbon Chemistry of Carbon
How many hydrogen atoms are needed to make up one molecule of the compound
C C C

34. Unique Properties of Carbon
Chemistry of Carbon
Unique Properties of Carbon

36. C C C Unique Properties of Carbon Chemistry of Carbon
How many hydrogen atoms are needed to make up one molecule of the compound
C C C

37. Carbon-based molecules
Chemistry of Carbon
Carbon-based molecules
(macromolecules, biomolecules, organic molecules)
Macromolecules = large, complex molecules such as lipids, carbohydrates, proteins and nucleic acids
Monomer = single unit
Polymer = many “units” linked together through polymerization

38. 1. Carbohydrates (sugars and starches)
Chemistry of Carbon
1. Carbohydrates (sugars and starches)
Structure:
Contain carbon, hydrogen and oxygen
Hydrogen : oxygen ratio is 2:1
Function:
Quick energy
Structural support (cell walls and cell membranes)
Other info:
Monomer = monosaccharide (simple sugar)
Examples: glucose, fructose
Polymer = polysaccharide
Examples: glycogen, starch, cellulose

39. What does each brown shape represent?
Is each brown shape a monomer or polymer?

40. 2. Lipids (fats, oils, waxes)
Chemistry of Carbon
2. Lipids (fats, oils, waxes)
Structure:
Contain carbon, hydrogen and oxygen (NO 2:1 hydrogen : oxygen ratio)
Contain long hydrocarbon chains
Function:
Long-term energy (storage)
Structural support (cell membranes)
Waterproof coverings (bird feathers)
Hormones (chemical messengers
Other info:
Hydrophobic (not soluble in water)
Not a true monomer: made up of glycerol and fatty acids
Saturated vs unsaturated lipids

41. 2. Lipids (fats, oils, waxes) continued
Chemistry of Carbon
2. Lipids (fats, oils, waxes) continued
Other info:
Saturated fatty acids have all single bonds between carbons in chain
unsaturated fatty acids may have one or more double bonds between carbons in chain

42. 2. Lipids (fats, oils, waxes) continued
Chemistry of Carbon
2. Lipids (fats, oils, waxes) continued
Which of the four fatty acids is saturated?
Which of the fatty acids are unsaturated?
How does melting point change as the # of carbon-carbon double bonds increases?
Which fatty acid is solid at room temperature?
Which is liquid at room temperature?

43. Saturated or Unsaturated?

44. Carb or Lipid?

45. Carb or Lipid?
Venn Diagram
Crash Course

46. 3. Nucleic Acids Chemistry of Carbon Structure: Function: Other info:
contain C, H, O, N AND P
Function:
store and transmit hereditary material
Other info:
monomer = nucleotide
Polymer = DNA and RNA

47. 4. Proteins Chemistry of Carbon ENERGY Structure: Function:
Contain C, H, O and N
Function:
Control chemical reaction rate
Regulate cell processes (transport)
Help fight disease
Transport substances around the body
Other info:
Monomer = amino acid
Polymer = polypeptide chain
Shape is crucial for a proteins function
Amino acid sequence determines shape of protein

50. WHO AM I? I store hereditary material.
I am made up of monosaccharides.
I give cells QUICK energy.
I contain the elements C, H, O and N.
My monomer is the nucleotide.
My monomer is the amino acid.
I am used for long-term energy storage.
I am a hydrocarbon chain.
I am a hydrocarbon chain with NO double bonds.

51. Carb, lipid, protein or NA?

52. Carb, lipid, protein or NA?

53. Carb, lipid, protein or NA?

54. Carb, lipid, protein or NA?

55. Monomer or polymer? Glucose monosaccharide Starch Nucleotide cellulose
Protein
Amino acid
Glycogen
polysaccharide
Carbon compounds flipchart
Keystone MC carbon compounds

56. Chemical Reactions Chemical Reactions
Chemical bonds between atoms are broken and rearranged to form new substances
Reactants = what you start with
Products = what you end with

57. Chemical Reactions Chemical Reactions
Dehydration synthesis = joins monomers together to form polymers
Water is a product of the reaction

60. Chemical Reactions Chemical Reactions
Hydrolysis= breaks a polymer down into monomers
Water is a reactant of the reaction
Reverse of dehydration synthesis

61. Quick Check Chemical Reactions
Which of these is not produced during dehydration synthesis?
Water
Glucose
Phospholipid
starch

62. Energy and Chemical Reactions
Activation energy = energy needed to get a reaction started
Chemical reactions that release energy are exothermic
Chemical reactions that absorb energy are endothermic

63. Exothermic Reactions release energy
Chemical Reactions
Exothermic Reactions release energy

64. Endothermic Reactions absorb energy
Chemical Reactions
Endothermic Reactions absorb energy

65. ENDOTHERMIC or EXOTHERMIC?
Pre-Class
ENDOTHERMIC or EXOTHERMIC?

66. The role of catalysts Chemical Reactions
A catalyst in general speeds up a chemical reaction
Lighter fluid is a catalyst
Enzymes are biological catalysts – they speed up chemical reactions by lowering the activation energy
Enzymes are proteins
Enzymes are not used up during a reaction

68. Enzyme Specificity Chemical Reactions Enzymes are specific
One enzyme generally catalyzes one reaction
Reactants of the reaction are called the substrates
Enzyme binds to substrate at an “active site”
Shape of the active site “fits” the shape of the substrates
Binding of the substrate with the active site causes the substrate to be converted to products

70. Enzymes and Optimal Conditions
Chemical Reactions
Enzymes and Optimal Conditions
Temperature
Optimum temp = the temp at which the enzyme works “the best”
High temperatures “denature” or unfold an enzyme, making it useless
Low temperatures slow pH activity

71. Enzymes and Optimal Conditions
Chemical Reactions
Enzymes and Optimal Conditions pH
Optimum pH = the pH at which the enzyme works “the best”
Different enzymes have different optimums
Enzymes in the stomach work best at a pH of 2 but enzymes in the small intestine work best at a pH of 8

72. Factors which may affect enzyme activity
Chemical Reactions
Factors which may affect enzyme activity
Substrate concentration
Remember, substrate = reactant of reaction
Initially, increasing substrate concentration will increase enzyme activity but eventually the reaction rate will level off

73. Factors which may affect enzyme activity
Chemical Reactions
Factors which may affect enzyme activity
Enzyme concentration
Increasing enzyme concentration will increase the rate of the reaction

74. How does the picture of the lock and key relate to enzymes?

75. Why is a cycle diagram a good way to show how enzymes work?

76. How does pH affect enzyme activity?

77. How does temperature affect enzyme activity?

78. How does substrate concentration affect enzyme activity?

79. How does enzyme concentration affect enzyme activity?