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Honors Biology Ch. 6

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Honors Biology Ch. 6 The Chemistry of Life I. Atoms, Elements, and Bonding - Living and nonliving are made of atoms A. Element - pure substance of only 1 type of atom ... – PowerPoint PPT presentation

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Title: Honors Biology Ch. 6


1
HonorsBiology Ch. 6
  • The Chemistry of Life

2
I. Atoms, Elements, and Bonding
  • - Living and nonliving are made of atoms
  • A. Element
  • - pure substance of only 1 type of atom
  • - 90 natural elements
  • - CHNOPS

3
The Size of Cells and Their Components
4
B. Atoms
  • - smallest unit of matter
  • 1. Nucleus contains
  • Charge Mass - Protons positive 1
  • - Neutrons neutral 1
  • 2. Electrons negative 0

5
Three Subatomic Particles
Proton
  • Heavy
  • Positive

Neutron
  • Heavy
  • Neutral

Electron
  • Light
  • Negative

6
Atomic Models
ElectronShell
Nucleus
Hydrogen (H)
Helium (He)
7
C. Isotopes
  • - forms of an element with varying number of
    neutrons
  • - C12 vs. C14

8
D. Compounds and Bonding
  • - 2 or more elements chemically bonded
  • 1. Covalent Bonds
  • - attraction due to shared electrons
  • - ex. water

9
Water Is Covalent
  • Electron pair forms covalent bond

Each spends some time w/one, then the other atom
10
Oxygen Molecule (O2)
Oxygen Atom
Oxygen Atom
11
2. Ionic Bonds
  • - attraction due to electrons transferred from
    one atom to another creating and - ions
  • - ex. table salt (NaCl)

12
Ionic Bonding in NaCl
Sodium has 1 electron in outer shell chlorine
has 7.
  • Sodium can lose 1 electron Chlorine can gain 1
    electron. Sodium becomes a positive ion Chlorine
    a negative ion.

13
Ionic Bonding in NaCl
  • Opposites attract.
  • Sodiums nestle between chlorines.
  • Perfectly cubical crystals.

14
Most Elements Molecular
Hydrogen gas One electron from each hydrogen atom
is shared, forming a single covalent bond
Oxygen gas Two oxygen atoms share four electrons,
forming a double bond
15
E. Acids, Bases, and pH
  • 1. Acids
  • - form H ions in solution
  • 2. Bases
  • - form OH- ions in solution
  • 3. pH
  • - measure of how acidic or basic a solution is
  • - logarithmic scale

16
The pH Scale
Water
NeutralpH pOH
17
II. Water and Diffusion
  • A. Water Is Polar
  • - water molecules have positive and negative
    ends

18
A. Water Is Polar
19
Hydrogen Bonds
Water molecules carry slight charges Electrons
favor O over H
Hydrogen bonds form between O of one and H of
another


O
H

H

O
H

HydrogenBonds

H

20
A. Water Is Polar
  • - polarity gives special properties
  • - universal solvent
  • - strong cohesion and adhesion
  • - high specific heat
  • - good evaporative coolant
  • - less dense when frozen

21
Cohesion among Water Molecules
22
NaCl Dissolved by Water
NaCl is ionicly bonded
Water is polar and charged
O sticks to Na
H sticks to Cl-
23
B. Diffusion
  • - movement of molecules from high concentration
    to low conc.
  • - until equilibrium reached

24
B. Diffusion
Diffusion
25
III. Organic Compounds
  • - Living organisms are made up of organic
    compounds
  • - CHNOPS
  • - main elements found in living organisms

26
A. 2 Major Differences Between
  • Living vs. Nonliving Systems Systems
  • complex simple compounds compounds
  • high energy low energy

27
- All organic compounds contain carbon
  • (exceptions CO2, CO, CaCO3)

28
- Carbon can form 4 covalent bonds
29
- Carbon can form 4 covalent bonds
  • - Carbon based molecules form chains, branched
    chains, rings, etc.

30
Buckminsterfullerene
31
B. 4 Classes of Organic Compounds
  • 1. Carbohydrates
  • 2. Lipids
  • 3. Proteins
  • 4. Nucleic Acids

32
IV. Carbohydrates
  • - contain C, H, O (121)
  • - include sugars, starches, cellulose
  • - used for energy storage and to build cell walls
  • - names usually end in "-ose"

33
A. Monosaccharides
  • - single (simple) sugar

34
A. Monosaccharides
  • - single (simple) sugar
  • - C6H12O6, C5H10O5
  • - ex. glucose (source of energy in cells),
    fructose (fruit sugar), galactose

35
B. Disaccharides
  • - double sugar

36
B. Disaccharides
  • - double sugar
  • - C12H22O11
  • - ex. sucrose (table sugar), lactose (milk sugar)

37
C. Polysaccharides
38
C. Polysaccharides (many sugars)
  • 1. Starch
  • - Made of many 10 - 1000 glucose molecules
  • - in plants (potatoes, grains)
  • - Glycogen animal starch

39
2. Cellulose
40
2. Cellulose
  • - long starch chains bonded side by side
  • - very strong
  • - found in the plant cell walls

41
V. Lipids
  • - fats, oils, waxes, steroids
  • - not soluble in water
  • - more energy (calories) in lipids than in
    carbohydrates
  • - energy storage, insulation, cell membrane,
    coatings

42
Triglycerides
Glycerol
3 Fatty Acids
43
Lipid Structure
44
Saturated vs. Unsaturated
Animal fat
Vegetable oil
45
What are trans fatty acids?
Carcinogenic
Natural
46
(No Transcript)
47
Cell Membrane
Phospholipid bilayer
48
Steroids
Cholesterol
49
VI. Proteins
  • - the most abundant and varied of organic
    compounds
  • - contain C, H, N, O (S)

50
A. Types of protein
  • 1. Structural - keratin (hair,
    fingernails), collagen
  • 2. Contractile - actin and myosin (muscle)
  • 3. Pigments - melanin (in skin, hair, iris)

51
  • 4. Hormones - regulate body functions
    (insulin)
  • 5. Antibodies - fight disease
  • 6. Enzymes - amylase (in saliva), lactase

52
B. Structure of Proteins
  • - very complex
  • - 3 basic shapes
  • 1. helix (coil)
  • 2. pleated sheet
  • 3. globular

53
Tertiary Protein Structure
Secondary Structure
Helix
Pleated Sheet
Random Coil
Tertiary Structure
Tertiary Structure
Globular
54
1. Amino Acids
  • - building blocks of proteins
  • - 20 different amino acids
  • - proteins contain between 50 - 2000 amino acids

55
2. Peptide Bond
  • - joins 2 amino acids
  • - dipeptide 2 amino acids
  • - polypeptide many amino acids

56
Primary and Secondary Structure of Protein
57
Peptide Bond
58
C. Enzymes
  • - protein catalysts
  • - speed up chemical reactions
  • - each enzyme catalyzes only one specific
    substrate
  • - most function at a specific temperature and pH

59
C. Enzymes
60
VII. Nucleic Acids
  • - 2 major types
  • A. DNA
  • - contains hereditary information (genes)
  • - double helix
  • B. RNA
  • - controls protein synthesis
  • - single helix

- 2 major types A. DNA - contains hereditary
information (genes) - double helix
61
Information Flow
62
The End
63
Bonding Patterns of Common Atoms
Hydrogen
     
Carbon
Nitrogen
Oxygen
Phosphorus
Sulfur
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