1. The Chemical Context of Life
Image by Riedell
KEY CONCEPTS:
2.1 Matter consists of chemical elements in pure form and in combinations called compounds.
2.2 An elements properties depend on the structure of its atoms
2.3 The formation and function of molecules depend on chemical bonding between atoms
2.4 Chemical reactions make and break chemical bonds.

2. Click the image to play the video segment.
Atomic Structure 2A
Click the image to play the video segment.
Video 1

3. What is an atom?
Basic unit of matter

4. The center of an atom called a
Nucleus

5. The particles found in the nucleus:
Proton (+)
Neutron (0)

6. The particle found in the energy level cloud around the nucleus:
Electron (-)

7. What is an element?
Pure substance that contains only one type of atom

8. Which elements make up 96% of the mass of a human?
Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)

9. MOLECULES CAN BE SHOWN IN DIFFERENT WAYS
Water molecule:
H2O
Other Images by: Riedell

10. Symbol
A one or two letter abbreviation is called a chemical symbol.

11. Atomic Number
# of protons

12. Atomic Mass
# of protons + # of neutrons

13. A compound
Atoms of 2 or more different elements chemically joined

14. Covalent bonds
share electrons (e-)
Example
Water (H2O)

15. Ionic bonds transfer electrons (e-) Example
Table salt (sodium chloride – NaCl)

16.  Properties of Water

17. WATER is important for all living things
Average person ~~ 60-70% water
Babies ~~ 78%
Human brain ~~ 90%
Image from:

18. Characteristics of WATER:
Water is polar
Water resists temperature changes
Water expands when it freezes
Water is cohesive – it sticks to itself
Water is adhesive – it sticks to other stuff
Water has surface tension – ex. A bug walks on water
Water can diffuse

19. Water is a polar molecule
Atoms in covalent bond that do not share electrons equally [has (+) & (-) ends]
Typically dissolves in H2O
Example of a polar molecule
H2O

20. - + Polar Molecules electric charge Because of the location of
Image from:
Because of the location of
electrons in molecules,
some molecules have an
_________ pattern of
____________________
More ___ on one side;
More ___ on the other
EX: water
UNEVEN
electric charge + -
Bending water video
More about this in Chapter 7

21. The same molecule can have both POLAR and NON-POLAR parts
EX: PHOSPHOLIPIDS
The same molecule can have both POLAR and NON-POLAR parts
Polar head
NON-polar tails
More about this in Chapter 7
Image by Riedell

22. Hydrogen bond
Weak bond created by a hydrogen atom attracted to oppositely charged atoms
Ex: Water – 2 Hydrogens (+) + 1 Oxygen (-) = H2O

23. HYDROGEN BONDS positively
Bonds that form between the _________ charged _____________
in one molecule and a
__________ charged _________
in a nearby molecule are called
_____________________
positively
HYDROGEN atom
negatively
atom
HYDROGEN BONDS
EX: water molecules
are held together
by Hydrogen bonds
Hydrogen bond animation
Images from:

24. Water Resists Temperature Change
Water has a high specific heat capacity, which is the amount of energy that it takes to raise the temperature of 1 gram of a substance by 1°C. In other words, it takes a lot of energy to heat water. 
Which takes longer to heat up? A pot with water or a pot without water?

25. Water expands when frozen

26. Water is cohesive
Cohesion is an attraction between molecules of the same substance. Because of hydrogen bonding, water is extremely cohesive

27. Water is adhesive
Adhesion is an attraction between molecules of different substances.

28. Water has surface tension
The cohesive forces between liquid molecules are responsible for the phenomenon known as surface tension. The molecules at the surface do not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the surface. This forms a surface "film" which makes it more difficult to move an object through the surface than to move it when it is completely submerse

30. Water can diffuse

31. “Like dissolves like” HYDROPHILIC
____________________ means “water loving”
_________ groups/molecules try to _________ and touch water or ______________ molecules
POLAR
be near
other polar
Water makes a great solvent in
living things because so many
molecules found in living things
are polar or have a charge.

32. “Like dissolves like” HYDROPHOBIC NON-polar
“Like dissolves like”
HYDROPHOBIC
_________________ means “water fearing”
___________ groups/molecules try to _________ other __________ molecules and __________ ________ molecules
NON-polar
be near
NON-polar
away from
polar
Oil based paints dissolve
in solvents such as
turpentine
. . . not water.

33. “Like dissolves like” SOAP
“Like
dissolves
like”
SOAP
______ works because it has a _____________ that dissolves _______ and a __________ that dissolves in _____ to wash away oily dirt.
NON-polar end
grease
Polar end
water

34. Mixture Substances are combined, but each keeps its own properties
Example
Salt/ sugar, Saltwater

35. Solution
Mixture of one or more substances (one being dissolved and the other does the dissolving)

36. Solute
Substance being dissolved in a solution

37. Solvent Substance doing the dissolving in a solution
Lemonade = solution (solvent= water, solute = sugar, lemon juice)

38. Hydrogen Ions (H+) H+ acidic More H+ = more acidic
The number of ____ ions determines how _______ a solution will be. H+
acidic
More H+ = more acidic

39. pH Measure of how acidic or basic a solution is
1-6 = Acidic ; 7 = Neutral; = Basic

41. Acid
Below 7 ; more H+ than OH-
Ex: lemon juice, milk, HCl

42. Neutral 7
Ex: pure water (equal amount of H+ and OH-)

43. Base
Above 7 ; less H+ than OH-
Ex: ammonia, drain-o, eggs, soap

44. Organic chemistry
is the study of all compounds that contain bonds between carbon atoms.

45. _________ is the most important atom found in living things CARBON
four
It can join to _______
other atoms at same time
chains
It can form ______ or _____
so it can make lots of
different kinds of molecules.
rings
Images from:

46. __________ molecules are found __________ and _____________ atoms
__________ molecules are found __________ and _____________ atoms
ORGANIC
in living things
contain CARBON

47. The 4 types of organic compounds are
Carbohydrates
Lipids
Proteins
Nucleic Acids

48. Macromolecules
giant molecules made up of many monomers (smaller units) joined together to form polymers

49. POLYMERIZATION kind of synthesis small subunits similar
_________________ is a
________________ reaction in which many _____________ that are ________ join to make
a bigger molecule
These small units are called ______________
The big molecule they make is called a
_____________
kind of synthesis
small subunits
similar
MONOMERS
POLYMER
Image by RIedell

50. Carbohydrates
Composed of the elements: C, H, and O with a ratio of 2 Hydrogens to every 1 oxygen
Building blocks are: simple sugars called monosaccharides
Used for: energy and storage

51. Types of carbohydrates
1. Simple Sugar-monosaccaride, a single sugar molecule
Examples:
Glucose (C6H12O6) – plants produce this during photosynthesis
Fructose – found in fruit
Galactose – found in milk

52. C6H12O6 NOTE: Glucose and Fructose are isomers
Isomers = same formula but a different arrangement of elements

53. 2. Disaccharides – two simple sugars joined by a saccharide bond
Examples:
Sucrose – table sugar
Lactose – milk sugar
Maltose – found in malted beverages (malt, beer)
Forming a disaccharide:
Monosaccharide + Monosaccharide  Disaccharide

54. 3. Polysaccharide – many simple sugars joined by a saccharide bond
Examples:
Starch – stores glucose in roots of plants (ex: potatoes); important food source for humans
Glycogen – stores glucose in liver cells in humans
Cellulose – found in plant cell walls to make more rigid
Chitin – found in the exoskeleton of arthropods
Forming a polysaccharide
Three or more monosaccharides combine to form a polysaccharide.

55. Lipids
Composed of the elements: H, and O but contains fewer O’s than carbohydrates
Building blocks are: glycerol and fatty acids
Used for: used to store energy, important parts of biological membranes and waterproof coverings protection, cushion, structure, insulation,
Types of lipids
Fatty acids
Saturated – solids at room temperature (animal fats)
Unsaturated – liquids at room temperature (vegetable oil)
Phospholipids – make up cell membranes

56. Saturated and Unsaturated

57. Proteins Composed of the elements: C, H, O, and N
Building blocks are: polymers called amino acids held together by a peptide bond
Used for:control the rate of reactions and regulate cell processes, cellular structures, transport substances into and out of cells, helps fight disease
Examples of proteins: antibodies, muscles, enzymes, hair

58. Proteins structure and function
- amino acids are joined together by covalent bonds
levels of organization
- amino acids are assembled using instructions found in DNA

60. Nucleic Acids Composed of the elements: C, H, O, N and P (Phosphorus)
Building blocks are: monomers called nucleotides which are made of a
Simple sugar – deoxyribose for DNA and ribose for RNA
Phosphate group
Nitrogen base – adenine, cytosine, guanine, and thymine for DNA and adenine, cytosine, guanine, and uracil for RNA
Used for: controlling cellular activities and making proteins (genes)
Examples of nucleic acids: DNA and RNA

61. Nucleic Acids joined by covalent bonds
-store and transmit hereditary, or genetic information. EX: DNA and RNA

62. Enzymes Made of proteins
Act as a catalyst – speeds up the rate of chemical reactions
Can catabolize (breakdown) or anabolize (build up) molecules
Hydrolysis (Decomposition) – a whole breaks down into its parts
Dehydration Synthesis – two parts come together to make a whole

63. Chemical reactions can also ________ molecules apart.
______________ = kind of chemical reaction in which a molecule is broken apart by adding a________ molecule.
“_____” = water “_____” = break apart
break
HYDROLYSIS
WATER
hydro
lysis
See an animation

64. opposite HYDROLYSIS is the _________ of DEHYDRATION SYNTHESIS.
Adding a water molecule breaks the bond.

65. One way to join molecules to make a bigger molecule is by ________
a _______ molecule to make a bond.
= ____________________ reaction
removing
WATER
dehydration synthesis
See an animation

66. DEHYDRATION SYNTHESIS “dehydration” “synthesis”
=_____________ _____________
water loss
put parts together

67. A chemical equation tells what happens in a chemical reaction
when molecules interact.
H + 2O → H20
_______________ ________________
Molecules that react Molecules that are
produced →
REACTANTS
PRODUCTS
Image by RIedell

69. REMEMBER: ALL the chemical reactions that happen in cells = _____________
METABOLISM
join
Chemical reactions can _____
molecules together.
Chemical reactions can ______
molecules apart.
break

70. Energy in Reactions
chemical reaction that release energy often occur on their own, or spontaneously
- chemical reactions that absorb energy will not occur without a source of energy
- activation energy – the energy needed to get a reaction started

71. Enzymes
catalyst - a substance that speeds up the rate of a chemical reaction
enzyme – a protein that acts like a biological catalyst. They speed up chemical reactions that take place in cells - lowers activation energy in a reaction

72. Enzyme Substrate Complex
provide a site for chemical reactions to take place
reducing the energy needed for the reaction
reactants in these reactions are called substrate
substrates bind to the active site (fit like a lock and key)