1. THE CHEMISTRY OF LIFE

2. Life depends on chemistry
Millions of chemical reactions occur in living organisms every day.
Organisms rely on chemical reactions in order to function.
Food must be broken down, gases must be exchanged, molecules must be built.

3. Carbon Electrons (-) Hydrogen Nitrogen Protons (+) Oxygen Phosphorus
Atom: smallest basic unit of matter
Electrons (-)
Protons (+)
Neutrons (no charge)
Element: substance made of only one type of atom that cannot be broken down by chemical means
CHNOPS: most commonly found elements in living thing
Carbon
Hydrogen
Nitrogen
Oxygen
Phosphorus
Sulfur

4. Periodic Table of Elements
There are more than 100 known elements
Each is represented by a 1, 2, or 3 letter symbol

5. HOW ARE LIVING THINGS PUT TOGETHER?
Compound
A chemical substance made of elements bonded together in fixed proportions
Example: Water is always 2 hydrogens and 1 oxygen bonded together.
Example: when sodium (Na) binds to chlorine atoms (Cl) the result is sodium chloride (NaCl): table salt!
Compounds are written as chemical formulas
The letter indicates the element and the number indicates how many
Example: Glucose or C6H12O6
6 carbons
12 hydrogens
6 oxygens

6. Ion: atom that has gained or lost one or more electrons
Bonds
Ionic Bond:
chemical bond formed through the electrical force between oppositely charged ions
Ion: atom that has gained or lost one or more electrons
Covalent Bond:
chemical bond formed when two atoms share one or more pairs of electrons
Molecule: two or more atoms held together by covalent bonds; not necessarily a compound
Hydrogen Bond:
attraction between a slightly positive hydrogen atom and a slightly negative atom

7. Polar versus Nonpolar Compounds
Polar compound: a compound whose molecules have a negative charge on one side and a positive charge on the other
Nonpolar compound: a compound whose electrons are equally distributed among its atoms

8. Water in Living Things Nearly 70% of your body is water!
2/3 of the molecules in your body are water molecules!
Why is water sooooooooo important?

9. Properties of water High Specific Heat:
water resists changes in temperature; it must absorb more heat energy to increase in temperature…water STORES ENERGY
Cohesion: attraction between molecules of the same substance
Surface tension: water (and other liquids) form thin films and drops
Adhesion: attraction between molecules of different substances
Capillary action: water molecules move upward through a narrow tube (ie a plant stem)

10. How many drops of water can fit on a penny?

11. Water Polarity Properties of Water
Enables many substances to dissolve in water
Ionic compounds and polar molecules dissolve best in water
Nonpolar molecules do not dissolve well in water (ie oil)

12. Many compounds dissolve in water
Solution
mixture that is consistent throughout; also called a homogenous mixture
Solvent
substance in which and that is present in greatest concentration in a solution
Solute
substance that dissolves in a solvent and is present at a lower concentration than the solvent

13. Some compounds form acids or bases
Water bonds are strong but they can break
H2O becomes…
H+ (hydrogen ions)
OH- (hydroxide ions)

14. pH Acids Bases Measurement of acidity
Related to free hydrogen ion (H+) concentration in solution
Acids
Compounds that form hydrogen ions (H+) when dissolved in water
The concentration of hydrogen ions (H+) in the solution is increased above that of pure water
Bases
Compounds that reduce the concentration of hydrogen ions (H+) when dissolved in water
Increase the hydroxide ion concentration (OH-)

15. pH Scale Based on the concentration of H+ in solutions
pH between 0 and 14
Each whole number represents a factor of 10 on the scale: for example, a solution with pH of 5 has 10X as many hydrogen ions as one with a pH value of 6
Water = 7
Acidic solutions < 7
Basic solutions > 7

16. Classwork/homework
Solutions, Acids and Bases worksheet (front and back)

17. Carbon-based molecules
Most matter in your body that is not water is made of organic compounds
Organic compounds: contain carbon atoms that are covalently bonded to other elements

18. Carbon atoms have unique bonding properties
Carbon forms the backbone or basic structure of all large organic molecules
Carbon can bond with up to 4 other atoms at once.
Carbon can form single, double or triple bonds.
Carbon bonds easily with other carbon atoms to form the backbone of large organic molecules
Carbon can bond with many different elements such as H, N, O, P, S
Monomer: molecular subunit of a polymer… a ”building block”
Polymer: large, carbon-based molecule formed by monomers

19. Four Organic Molecules
Macromolecules
most molecules in cells are so large they are called macromolecules or “giant molecules”
Polymerization
process by which small molecules called monomers are put together to make large molecules called polymers

20. Four main types of carbon- based molecules are found in living things
Carbohydrates
Lipids
Nucleic acids
Proteins

21. carbohydrates

22. Carbohydrates Composition: carbon, hydrogen and oxygen atoms 1:2:1
Monomers:
“Monosaccharides”
Simple sugars: glucose (C6H12O6) and fructose
Examples:
Disaccharides: double sugars formed when two monosaccharides are joined
Polysaccharides: chains of 3 or more monosaccharides (ie starch)
Starch: made by plants
Glycogen: made by animals
Cellulose: provides structural support for plants; humans cannot digest it
Function:
Key source of energy, found in most foods
Glucose is the main source of energy in cells

23. Lipids Composition: C,H, O Building Blocks: Examples: Function:
Contain 3 fatty acids bonded to a glycerol molecule backbone
Glycerol: a 3-carbon organic molecule
Fatty acid: a long chain of carbon atoms with hydrogen atoms bonded to them
Examples:
Fats and Oils
Phospholipids
Steroids
Waxes
Function:
Store energy
Compose parts of biological membranes
Waterproof coverings

24. Saturated Fatty Acids (Saturated Fats)
All of the carbon atoms in the chain are bonded to 2 hydrogen atoms
Most animal fats (butter, lard grease)
Most are solid at room temperature

25. Unsaturated Fatty Acids (Unsaturated Fats)
Some of the carbon atoms are linked by a “double” covalent bond, each with only 1 hydrogen atoms, producing kinks in the molecule
Most plant oils, i.e. olive oils, and some fish oils
Most are liquid at room temperature

26. Hydrogenated Vegetable Oils (Trans Fats)
Naturally unsaturated fatty acids that have been saturated artificially by the addition of hydrogen atoms
Margarine and vegetable shortening are therefore generally solid at room temperature

27. Saturated vs. Unsaturated

28. Hydrogenation

29. Phospholipids
Important part of the structure and function of cell membranes
Glycerol
2 fatty acids
A phosphate group
Make up the lipid bilayer of cell membranes
Hydrophilic and hydrophobic

30. STEROIDS AND WAXES
Steroids: include cholesterol, found in animal cell membranes
Steroids occur in animals in hormones
A four-ring structure, one with five carbons and three with six carbons in the rings
Waxes: are used to coat and protect things in nature.
Bees…plants…your ears!

31. Nucleic Acids Composition: C,H,N,O,P Monomers/Building Blocks:
Nucleotides
Sugar
Base
Phosphate group
Examples:
DNA: deoxyribonucleic acid
2 strands of nucleotides
Sugar: deoxyribose
Bases: ATCG
RNA: ribonucleic acid
1 strand of nucleotide
Sugar: ribose
Bases: AUCG
Functions:
DNA: Stores hereditary information
RNA: Many key roles in the manufacture of proteins; can also act as a enzyme, promoting chemical reactions

32. Proteins Composition: C, H, N, O Monomers/Building Blocks: Examples:
Amino acids: the building blocks or proteins
20 different amino acids are found in proteins
Some are polar, some are nonpolars; some are electrically charged, some are not
Proteins fold into compact shapes
Examples:
Enzymes
Structural proteins
Antibodies
Specialized proteins
Function:
Increase reaction rate
Form cell membrane
Fight diseases
Build muscle

33. ATP Adenosine triphosphate
A single nucleotide with extra energy-storing phosphate groups
When food is broken down inside cells, some of the energy is stored temporarily as ATP; cells need it to function!

34. In summary…

36. Classwork/homework Chemistry of Life packet Frayer Model
Organic Molecules worksheet (front and back)
Investigating Organic molecules (cut-out)

37. Bonds break and form during chemical reactions
Chemical reaction: process by which substances change into different substances through the breaking or forming of chemical bonds
Reactants: the starting materials for chemical reactions
Products: the newly formed substances
Reactants  Products
 means “changes to” or “forms”
NaCl  Na+ + Cl-
Equilibrium: condition in which reactants and products of a chemical reaction are formed at the same time

38. Chemical reactions release or absorb energy
Activation energy: energy input necessary to initiate a chemical reaction; a chemical “push” that starts a chemical reaction
Exothermic/Exergonic Reactions: chemical reaction that yields a net release of energy in the form of heat, light, or sound; often occur spontaneously
Endothermic/Endergonic Reactions: chemical reaction that requires a net input of energy; absorb energy and do not occur without a source of energy

39. enzymes Without enzymes some cell processes would take too long!
Enzyme: protein that catalyzes chemical reactions for organisms
Enzymes work by lowering the activation energy of the reaction.
Enzymes temporarily bind to reactants to help them react so the shape of the enzyme is very important.
Enzymes are not altered during the reaction so they can catalyze the same reaction over and over.
pH and temperature affected how well enzymes work because they change the shape of the protein.

40. A catalyst lowers activation energy
Catalyst: substance that decreases activation energy and increases reaction rate in a chemical reaction

41. Enzymes allow chemical reactions to occur under tightly controlled conditions
Substrate: reactant in a chemical reaction upon which an enzyme acts

42. Enzyme Specificity
Substrate: a substance on which an enzyme acts during a chemical reaction
Enzymes only act on specific substrates
Active site: the site on an enzyme that attaches to the substrate
Video

43. Factors in Enzyme Activity
Any factor that changes the shape of an enzyme can affect it’s activity
Heat pH
Denaturation: the alteration of a protein shape through some form of external stress in such a way that it will no longer be able to carry out its cellular function

44. Chemical reaction occurs and substrates are changed to products.
Enzyme Action
Enzyme
Substrates
Products
Active site
Substrates bind to
enzyme at active site.
Products are
released. Enzyme
is available again.
Chemical reaction occurs and
substrates are changed to products.

45. Enzyme Action Product is Reactants bind released. Enzyme
is available again.
Reactants bind
to the enzyme at
the active site.
Chemical reaction
changes reactants
to products.

46. Classwork/homework
Practice with Reactions and Energy worksheet