The Chemistry of Life

1. C 6: T C
h he hemistry of Life
6.1 - Atoms and T heir
Interactions

2. Section 6.1
Inside This Section...
What is an Element?
What are Atoms?
2 Types of Chemical Bonds
Chemical Reactions

3. Section 6.1
What is an Element?
A substance that can not be
broken down into smaller
particles.
90 elements naturally occur on
earth
25 are essential to living things
Each element is identified by a
symbol

4. Section 6.1
Elements
C = Carbon Na = Sodium
Ca = Calcium

5. Section 6.1
Elements
K = Potassium Fe = Iron
N = Nitrogen

6. Section 6.1
Elements
AU = Gold

7. Section 6.1
Trace Elements
Elements that are present in small
amounts in the human body.
N,K,Ca, and Fe are a few examples
Help control cell metabolism
Plants obtain trace elements through their
roots while animals obtain trace elements
through what they eat.

8. Section 6.1
What is an Atom?
The smallest part of an element
that still maintains all the
characteristics of that element.
The basic building blocks of all
matter

9. Section 6.1
What is an Atom?
Nucleus: Center of the Atom
Electrons:
The outer particles
Negatively charged
Protons:
Particles found in the nucleus
Positively charged
Neutrons: Particles found in the nucleus that
have no charge.

10. Section 6.1
What is an Atom?
Electron and Proton numbers are always the same
Neutron (0)
Electron (-)
Proton (+)

11. Section 6.1
Energy Levels
Regions around the nucleus that
the electrons travel.Atoms like to
have their outer most energy level
full.

12. Section 6.1
Energy Levels & Electrons
Energy Level # of Electrons
1 2
2 8
3 18

13. Section 6.1
What are Isotopes?
Atoms of the same element that have different numbers of
neutrons.

14. Section 6.1
What are Isotopes?
Most carbon nuclei contain six neutrons
Some have 7 or 8
These three atoms are isotopes
We refer to the isotopes in terms of the combined total of
protons and neutrons
Carbon-12 has 6 protons and 6 neutrons
How many protons and neutrons does carbon-13 and carbon-
14 have??

15. Section 6.1
Problem Solving Lab 6.1
Read Problem Solving Lab 6.1
in groups of twos (pg 149)
Answer the 4 questions

16. Section 6.1
Compounds
A substance that is composed of two
or more different elements that are
chemically combined.
Properties of compounds are different
than those of their individual elements.
(NaCl)
Compounds can always be described
with an equation. (H20)

17. Section 6.1
Bond #1: Covalent Bonds
When two elements share electrons in
their outer energy level.
Atoms are the happiest when their
outer energy level is full.
Water is an example

18. Section 6.1
Bond #2: Ionic Bond
A bond between atoms that is formed by
losing and gaining an electron.
NaCl is an example
Na has one electron in its outer shell
Cl has 7 in its outer shell
The two oppositely charged atoms now
attract each other like magnets.

19. Section 6.1
Chemical Reactions
Chemical reactions occur when bonds
between compounds are broken or
formed.
Chemical reactions must have the right
environment
pH
Temperature
Energy
Concentration

20. Section 6.1
Chemical Equations
Reactant + reactant --> Product
Reactants undergo chemical reactions
Products are formed in chemical reactions
2H2 + O2 --> 2H2O
Key Point: atoms are never created or destroyed

21. Section 6.1
Metabolism
All of the chemical reactions that
occur in the human body.
Produce energy
Require energy
Build necessary molecules for
bodily functions

22. Section 6.1
Solutions and Mixtures
Solution: A mixture in which Mixture: A combination of
one or more substances are substances in which the
evenly distributed in another individual components
substance. retain their chemical
properties.Sand and Salt
Salt Water
Kool-Aid

23. Section 6.1
pH Levels
pH is a measure of how acidic or basic a substance is.
Scale of 0-14
pH paper is used to determine the pH level
A pH below 7 is acidic
A pH above 7 is basic
A pH of 7 is neutral (Water)

24. Section 6.1
pH Levels

25. Section 6.1
Acid
Any substance that forms
hydrogen ions in water.
H+
When HCl is put into water
H+ and Cl- ions.

26. Section 6.1
Base
Any substance that forms
hydroxide ions in water.
OH-
When NaOH is put in water
you get Na+ and OH- ions.

27. Section 6.1
Common Acids and Bases
Acids Bases
Orange Juice Toothpaste
Stomach Acids Baking Powder
Tomato Juice Chlorine Bleach

28. Section 6.1
In Review...
What is an Element?
What are Atoms?
2 Types of Chemical Bonds
Chemical Reactions

29. Section 6.2
Jump Start
What are some
characteristics of water?
How do organisms use
water to live and grow?

30. C 6: T C
h he hemistry of Life
6.2 - Water and Diffusion

31. Section 6.2
Inside This Section...
The Importance of Water
The Characteristics of Water
Bond #3: Hydrogen Bonds
Diffusion

32. Section 6.2
The Importance of Water
Most life processes occur only
in water
Helps to transport materials in
organism
70 to 95% of most organisms is
Water

33. Section 6.2
The Characteristics of Water
Water is polar
Water sticks but isn’t sticky
Capillary action: able to creep
up thin tubes
Water resists temperature changes
Water expands when it freezes

34. Section 6.2
Water is Polar
Water (H2O) contains two hydrogen atoms and one Oxygen atom
that are covalently bonded to each other
The Shared electrons are more attracted to the Oxygen atom
than to the hydrogen atoms (Unequal sharing)
Results in a polar molecule: It has a positive and a negative end
Polar likes polar (i.e. Ionic compounds like salt and other polar
molecules like sugar)

35. Section 6.2
Bond #3: Hydrogen Bonds
Because water molecules have a positive
end and a negative end, there will be an
attraction between water molecules
This results in Hydrogen Bonds between
the oxygen atom of one molecule and
the hydrogen atom of another
Weaker Bond

36. Section 6.2
What Resists Temperature Change
It takes a lot of energy to increase
its temperature
Loses a lot of heat when it cools
These features help maintain a
steady environment (i.e. in cells)

37. Section 6.2
Water expands when it freezes
Ice Floats - less dense
What would happen to lake
Michigan if ice was more dense
than water?

38. Section 6.2
Brownian Motion
Anything that is moving has kinetic
energy
If you look at the molecules of
gasses, liquids and some solid
molecules under a very powerful
microscope, you will see that they
are randomly moving --> Brownian
motion

39. Section 6.2
Diffusion
Diffusion: The net movement of particles from an area of
higher concentration to an area of lower concentration.
A very slow process --> Relies on random molecular motion
(Brownian motion)
Affected by 3 factors
Concentration (most important factor)
Temperature
Pressure

40. Section 6.2
Diffusion

41. Section 6.2
Diffusion
Diffusion continues until the two substances are distributed
evenly --> Dynamic Equilibrium
Concentration gradient: the difference in concentration of a
substance across space.
At dynamic equilibrium, there is no concentration gradient

42. Section 6.2
In Review...
The Importance of Water
The Characteristics of Water
Bond #3: Hydrogen Bonds
Diffusion

43. C 6: T C
h he hemistry of Life
6.3 - Life Substances

44. Section 6.3
Inside This Section...
The Structure of Carbon
Carbohydrates
Lipids
Proteins
Nucleic Acids

45. Section 6.3
Carbon
Carbon has 4 electrons in its outer
energy level
Can form 4 covalent bonds with other C
elements
Can also bond with other carbon
atoms

46. Section 6.3
Carbon
3 types of bonds:
Single bond: each atom shares 1
electron
C
Double bond: each atom shares 2
electrons
Triple bond: each atom shares 3
electrons

47. Section 6.3
Carbon
C C
C C

48. Section 6.3
Carbon
C C
C C

49. Section 6.3
Carbon
Carbon atoms can form straight
chains, branched chains, or rings and
can bind to other elements
C
Can form a whole bunch of carbon
structures

50. Section 6.3
Simple Formulas
Water - H2O
Glucose - C6H12O6
Isomers: Same simple formula but
different 3D structure
Glucose and Galactose are both
C6H12O6

51. Section 6.3
Molecular Chains
Large molecules are called macromolecules (e.g. proteins)
Macromolecules are formed by binding together smaller
molecules into chains (Polymer)

52. Section 6.3
Condensation and Hydrolysis
Condensation: Chemical reaction by which polymers are
formed (water is removed)
Hydrolysis: Chemical reaction by which polymers are broken
apart (water is used)

53. Section 6.3
Carbohydrates
Organic compound composed of
Carbon, hydrogen and oxygen.
2 H’s and 1 O for every carbon
Simplest type is monosaccharides like
glucose and fructose.

54. Section 6.3
Carbohydrates
Two monosaccharides bind to form a
disaccharide (i.e. Sucrose = glucose +
fructose)
Many monosaccharides bind to form
polysaccharides (i.e. starch and
cellulose - glucose polymers)

55. Section 6.3
monosaccharide (glucose)
disaccharide (sucrose)
polysaccharide (starch)

56. Section 6.3
Lipids
Lipids are fats and oils.
Organic compound with a large
proportion of C-H bonds and less
oxygen than carbohydrates.
Nonpolar
Used in cells for energy storage,
insulation and protection.

57. Section 6.3
Lipids
Most commonly 3 fatty acids bound to a glycerol molecule.
(pg 164)

58. Section 6.3
Proteins
Provide structure for tissues and organs
Carry out cell metabolism
Large, complex polymer made of Carbon,
hydrogen, oxygen, nitrogen and usually
sulfur.
Building blocks are various combinations
of amino acids
Amino acids join together with peptide
bond

59. Section 6.3
Proteins
An Enzyme is a protein that changes the rate of a chemical
reaction
Involved in almost all metabolic processes.
Speed up chemical reactions

60. Section 6.3
Nucleic Acids
Stores cellular information in the
form of a code.
Polymer of smaller subunits called
nucleotides.
Nucleotides consist of C, H, O, N, P
atoms.
Nucleotides make up our DNA

61. Section 6.3
Nucleic Acids
Nucleic acids have 3 parts:
Nitrogenous
A Base Phospha Base
te
A Simple sugar O O
A Phosphate group Sugar

62. Section 6.3
Nucleic Acids
Nitrogenous
Phospha Base
te
O O
Sugar

63. Section 6.3
In Review...
The Structure of Carbon
Carbohydrates
Lipids
Proteins
Nucleic Acids