1. Chapter 2

2. The atom

3. What is an Atom? Atom: Smallest unit of all matter 3 Main Parts:
Proton (+)
Neutron (0)
Electron (-)
Protons & Electrons usually equal in number
Elements (substance made of only 1 type of atom) are identified on the Periodic Table

4. Reading the Periodic Table
Atomic Number: Number of protons the atom contains
Usually # of electrons also
Atomic Mass: Combined # of protons and neutrons inside the nucleus
Electrons too small to affect mass

5. Reading the Periodic Table
How many protons, electrons, and neutrons does Carbon contain?
Protons = ______
Electrons = ______
Neutrons = ______ 6
Atomic Number: Number of protons the atom contains
Usually # of electrons also
Atomic Mass: Combined # of protons and neutrons inside the nucleus
Electrons too small to affect mass

6. Reading the Periodic Table
How many protons, electrons, and neutrons does Carbon contain?
Protons = ______
Electrons = ______
Neutrons = ______ 6 6
Atomic Number: Number of protons the atom contains
Usually # of electrons also
Atomic Mass: Combined # of protons and neutrons inside the nucleus

7. Reading the Periodic Table
6 + Neutrons = 12
How many protons, electrons, and neutrons does Carbon contain?
Protons = ______
Electrons = ______
Neutrons = ______ 6
Protons + Neutrons = 12 6 6
Atomic Number: Number of protons the atom contains
Usually # of electrons also
Atomic Mass: Combined # of protons and neutrons inside the nucleus
Electrons too small to affect mass

8. What’s the:
Atomic number = amount of protons
Atomic number = amount of protons
Atomic number = protons usually same as electrons
Atomic mass = amount of protons + neutrons
Atomic mass = amount of protons + neutrons 4
A) Atomic number of Beryllium? B) Atomic mass of Beryllium? C) How many protons? D) How many electrons? E) How many neutrons? 9 4 4 5

9. Electron Cloud Electrons orbit the nucleus in “energy levels”
1st level:
closest to nucleus
stable w/ 2 electrons

10. Electron Cloud Electrons orbit the nucleus in “energy levels”7
Electrons orbit the nucleus in “energy levels”
1st level:
closest to nucleus
stable w/ 2 electrons
2nd level:
stable w/ 8 electrons 1 6 8 5 1 4 2 2 3

11. Electron Cloud Electrons orbit the nucleus in “energy levels”
1st level:
closest to nucleus
stable w/ 2 electrons
2nd level:
stable w/ 8 electrons
Examine Carbon. It has 2 electrons in the first level and 4 electrons in the 2nd level. Is Carbon stable?

12. Electron Cloud Electrons orbit the nucleus in “energy levels”7
Electrons orbit the nucleus in “energy levels”
1st level:
closest to nucleus
stable w/ 2 electrons
2nd level:
stable w/ 8 electrons
3rd level:
Atoms are stable when the outermost level is “full” 7 6 8 1 8 6 1 5 1 5 2 2 4 4 2 3 3

13. Molecules Molecule: 2 or more atoms held together by a covalent bond
8 protons
8 electrons
Molecule: 2 or more atoms held together by a covalent bond
Form when atoms are unstable
Covalent Bond: Chemical bond where atoms share electrons
Ex: Oxygen (O2)
Why unstable? Only 6 electrons in outer energy level 6 1 1 5 2 4 2 3

14. Molecules Molecule: 2 or more atoms held together by a covalent bond
Form when atoms are unstable
Covalent Bond: Chemical bond where atoms share electrons
Ex: Oxygen (O2)
Why unstable? Only 6 electrons in outer energy level
What happens? Oxygen atom will share two electrons with neighboring oxygen atom
End result? Both end up with 8 electrons in outer level (stable)

15. Ionic Bonds e e e e e e e e e e e e e e e e e e e e e e e e e e e e + -
Ionic bond: chemical bond where electrons are gained/lost
Held together by magnetic attraction
Cause: 1 atom may steal an electron from another
Ion: + or – charged atom
Ex: Sodium + Chlorine = Sodium Chloride

16. Na Cl Na Cl 11+ 17+ 11+ 17+ 11- 17- 10- 18- +1 -1 Protons (+)
Na atomic number = 11 Before the bonding
Cl atomic number = 17 After the bond Na Cl
Protons (+)
Electrons (-)
Net charge Na Cl
Protons (+)
Electrons (-)
Net charge
11+
17+
11+
17+
11-
17-
10-
18- +1 -1

17. Recap Name the 3 subatomic particles.
Which subatomic particles are found inside the nucleus?
The atomic number usually allows us to determine the amount of which two subatomic particles?
If an atom has the atomic mass of 14 and the atomic number of 6, how many protons, neutrons, and electrons does the atom contain?
After an ionic bond is formed, what is the charge of the atom that gained an electron?
Which type of chemical bond shares electrons?

18. water H H O

19. + +
Water Basics 1 1 1 1
Polar: part of a molecule is slightly positive, while another part is slightly negative
Creates hydrogen bonds where one water sticks to another 1 2 6 1 5 2 3 4 -

20. Red = Oxygen (negative) White = Hydrogen (positive)- - - - - - - - - + + + + + + + + + + + + + + + + + + - - - - - - - - + + + + + + + + + + + + + + + + + + - - - - - - - - - + + + + + + + + + + + + + + + + + +

21. Water Properties High specific heat: Resists temperature changes
A lot of energy is needed to break bonds between water molecules
Helps to maintain a constant body temp (Homeostasis)
Cohesion: polar water molecules attracted to other polar water molecules
Adhesion: polar water sticks to other molecules
7ml
6.8ml
Why can this insect walk on water?
It is not heavy enough to break the bonds that hold the water molecules together.

22. Solutions Solution: mixture where 1 substance dissolves in another
2 parts to a solution
1) Solute: substance that dissolves
Atoms, ions, molecules
2) Solvent: substance in which the solute is dissolved in
Usually water S U G A R K O O L A I D

23. Solutions Ex: Human blood Solvent: Plasma (watery part of blood)
Solutes: Carbs, proteins, sugars, etc…

24. pH Scale
Acid
Base
Few H+
More H+
neutral
Few OH-
More OH-
Lemons
Soft drink
Milk
Blood
Baking soda
Ammonia
pH scale measures the amount of H+ ions in a solution
pH scale measures how acidic or basic a substance is and ranges from 0 to 14
1 minute: Discuss with your neighbor:
Which base has the most H+ ions?
Which substance has the fewest H+ ions?
Which is the strongest acid?
blood
Ammonia
Lemons

25. pH Scale Some molecules release H+ ion when dissolved
H+ ions accumulate (acids)
Acidic solution
Substance A H+ H+ H+ H+ H+ H+ H+ H+ H+

26. pH Scale Some molecules release OH- ions when dissolved
Basic (alkaline) solution
Some molecules release OH- ions when dissolved
OH- ions accumulate (bases)
OH-
OH-
OH-
Substance B
OH-
OH-
OH-
OH-
OH-
OH-

27. Recap
1) Name 4 basic features of water. 2) Which water property explains that one atom is positively charged, while another is negatively charged? 3) How does cohesion and adhesion differ? 4) Which is a stronger acid? Substance A with a pH of 5 or substance B with a pH of 3? 5) Which has more H+ ions? Substance A with a pH of 5 or substance B with a pH of 3? 6) How does a solute differ from a solvent?

28. Organic molecules

29. Organic Molecules Carbon = building block of organic molecules
6 protons
6 electrons
Carbon = building block of organic molecules
Carbon is unique
Unstable: 2nd level not full
Will bond up to four times 1 1 4 2 2 3

30. Organic Molecules Monomer: Small carbon molecules Ex: Amino acid
Polymer: chain of linked monomers
Ex: Protein
monomer
monomer
Polymer
monomer
monomer
monomer
monomer
monomer

31. Carbohydrates

32. Carbohydrates Readily available food source C1: H2: O1 ratio
Ex: Glucose = C6 H12 O6
Monomer: Monosaccharides
Simple sugars
Bond to form larger sugars
Polymer: Polysaccharide
Complex sugars
Fructose
(monosaccharide)
Glucose
(monosaccharide)
Sucrose
(disaccharide)

33. Carbohydrate Polymers: Polysaccharide
Polysaccharides: Long chain of monosaccharides
Ex: Starch: excess plant sugar converted & stored
Ex: Glycogen: animal starch stored in liver & muscles
Ex: Cellulose: used in plants to make cell walls
glucose
glucose
glucose
glucose
glucose

34. Recap
How many electrons does Carbon have in the 1st energy level? 2nd energy level?
Which type of organic molecule is most commonly used as energy for cells?
What are the monomers of carbohydrates called?
What are the polymers of carbohydrates called?
Which polymer is stored by animals?
Which polymer is stored by plants?

35. Lipids

36. 1 2 Lipid Structure Monomer: Fatty Acid Polymer: Lipid
Examples: Fats, Oils, Waxes
Phospholipid Structure (3 parts):
“Head” of glycerol & phosphate(polar)
“Tail” of 2 fatty acids (non-polar)
Make up the cell membrane
Phospholipid 1 2

37. Lipid Structure Triglyceride: Structure (2 parts) “head” = glycerol
Glycerol molecule
Triglyceride:
Structure (2 parts)
“head” = glycerol
“Tail” = 3 fatty acids
Function
Provide Energy for cells
Insulation
Cholesterol: Gives cell membrane flexibility

38. Saturated Fats Fats and oils have different types of fatty acids.
Long chain of carbon bonds (all single bonds)
Each C is “saturated” with H atoms
Single bonds are easier to compact = solid at room temps
Very common in animal fats
think

39. Unsaturated Fats Long chain of carbon bonds (some double bonds)
Prevent H from attaching
make “kinks”, which are not easily compacted = Liquid at room temps
Common in Plant fats
think

40. Normally, blood flows freely through a vein
Blood vein
RBC
RBC
RBC
RBC
RBC
RBC

41. Too much saturated fats…
Blood vein
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
RBC
Reduced circulation…
Blood clots…
High blood pressure
Cholesterol & saturated fats

42. Cholesterol levels

44. Recap What are the three parts of a phospholipid?
Which part(s) is/are the “head”?
Which part are the “tails”?
What are the two parts of a triglyceride?
How do saturated and unsaturated fatty acids differ?
Why are saturated fats less healthy?

45. Nucleic Acids

46. Nucleic Acid Basics Contain instructions to build protein 2 types DNA
RNA
Made up of smaller units called nucleotides
monomer = nucleotide
Polymer = nucleic acid

47. Nucleotides are made of three parts: a sugar phosphate group
nitrogen base.
- Adenine (A) Thymine (T)
- Guanine (G) Cytosine (C)
A phosphate group
nitrogen-containing molecule, called a base
deoxyribose (sugar)

48. Monomers link to make polymers
Monomers link to make polymers! Nucleotides combine to make nucleic acid! These are the instructions for the cell to make protein.

49. Nucleotides?
How many

50. DNA Double Helix: 2 chains of nucleotides
DNA stores the information required to make a protein
Gene: section of DNA that codes for a protein

51. RNA 1 chain of nucleotides
Copy the DNA code… deliver code to ribosome to create a protein

52. Recap Name the monomer of nucleic acids.
What are the four nitrogen bases of DNA?
Name the three parts to a nucleotide.
How are DNA and RNA different? Same?

53. Protein

54. Protein Basics Used in variety of cellular functions
Made of smaller amino acids
Monomer: Amino acid
Polymer: Polypeptide (Protein)
Only 20 amino acids… but thousands of proteins
Exact arrangement of amino acids determines the protein
leucine
valine
glycine
alanine
leucine
leucine
histi-
dine
aspara-
gine
serine
proline
= Protein A
valine
leucine
glycine
alanine
leucine
leucine
histi-
dine
aspara-
gine
serine
proline
= Protein B
Amino acids (monomer)

55. Amino acids are linked by peptide bonds.

56. Enzymes Types of proteins
Enzyme: Lowers the energy needed to start chemical reactions
ex: Break down food
Sensitive to pH, temp  can cause them to denature
ex: If high fever: enzymes lose ability to work
Very specific in actions (lock & key)
ex: Amylase: Breaks starch into simple sugars
Reusable
Enzyme amylase
glucose
glucose
glucose
glucose
Starch

57. Recap What are the smaller monomers that make proteins called?
How many different amino acids exist?
Which group of proteins help to start chemical reactions?
What can cause an enzyme to denature?
Explain the lock and key analogy as it relates to enzymes.

58. ENZYMES

59. Chemical Reactions Energy stored in chemical bonds
When bonds broken = Energy released (heat & light)
Activation Energy: amount of energy needed to start a reaction

60. Enzymes
Catalyst: substance that decreases the activation energy needed to start a chemical reaction
Speeds up reaction
Enzymes are catalysts in living organisms.

61. Enzyme Structure
Enzyme shape allows specific reactants to bind together
Reactants = substrate
Ex: Amylase & starch: Starch is the substrate because it binds to amylase
Substrates binds to activation sites on the enzyme (key fitting into a lock)
Once binded to enzyme, substrates bonds break
Substrates form new bonds (product)

64. Recap 1) How do enzymes speed up chemical reactions?
2) What is released when chemical bonds are broken?
3) Why is photosynthesis an example of an endothermic reaction?
4) Why is cellular respiration an example of an exothermic reaction?
5) Besides enzymes, what else is often a catalyst that speeds up reactions?
6) What are the molecules called that react with enzymes?
7) What do enzymes weaken between molecules?