Honors Biology Ch. 6

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HonorsBiology Ch. 6

• The Chemistry of Life

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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

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The Size of Cells and Their Components
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B. Atoms

• - smallest unit of matter
• 1. Nucleus contains
• Charge Mass - Protons positive 1
• - Neutrons neutral 1
• 2. Electrons negative 0

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Three Subatomic Particles
Proton

• Heavy
• Positive

Neutron

• Heavy
• Neutral

Electron

• Light
• Negative

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Atomic Models
ElectronShell
Nucleus
Hydrogen (H)
Helium (He)
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C. Isotopes

• - forms of an element with varying number of
  neutrons
• - C12 vs. C14

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D. Compounds and Bonding

• - 2 or more elements chemically bonded
• 1. Covalent Bonds
• - attraction due to shared electrons
• - ex. water

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Water Is Covalent

• Electron pair forms covalent bond

Each spends some time w/one, then the other atom
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Oxygen Molecule (O2)
Oxygen Atom
Oxygen Atom
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2. Ionic Bonds

• - attraction due to electrons transferred from
  one atom to another creating and - ions
• - ex. table salt (NaCl)

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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.

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Ionic Bonding in NaCl

• Opposites attract.
• Sodiums nestle between chlorines.
• Perfectly cubical crystals.

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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
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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

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The pH Scale
Water
NeutralpH pOH
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II. Water and Diffusion

• A. Water Is Polar
• - water molecules have positive and negative
  ends

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A. Water Is Polar
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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

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A. Water Is Polar

• - polarity gives special properties
• - universal solvent
• - strong cohesion and adhesion
• - high specific heat
• - good evaporative coolant
• - less dense when frozen

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Cohesion among Water Molecules
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NaCl Dissolved by Water
NaCl is ionicly bonded
Water is polar and charged
O sticks to Na
H sticks to Cl-
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B. Diffusion

• - movement of molecules from high concentration
  to low conc.
• - until equilibrium reached

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B. Diffusion
Diffusion
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III. Organic Compounds

• - Living organisms are made up of organic
  compounds
• - CHNOPS
• - main elements found in living organisms

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A. 2 Major Differences Between

• Living vs. Nonliving Systems Systems
• complex simple compounds compounds
• high energy low energy

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- All organic compounds contain carbon

• (exceptions CO2, CO, CaCO3)

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- Carbon can form 4 covalent bonds
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- Carbon can form 4 covalent bonds

• - Carbon based molecules form chains, branched
  chains, rings, etc.

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Buckminsterfullerene
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B. 4 Classes of Organic Compounds

• 1. Carbohydrates
• 2. Lipids
• 3. Proteins
• 4. Nucleic Acids

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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"

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A. Monosaccharides

• - single (simple) sugar

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A. Monosaccharides

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

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B. Disaccharides

• - double sugar

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B. Disaccharides

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

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C. Polysaccharides
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C. Polysaccharides (many sugars)

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

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2. Cellulose
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2. Cellulose

• - long starch chains bonded side by side
• - very strong
• - found in the plant cell walls

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V. Lipids

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

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Triglycerides
Glycerol
3 Fatty Acids
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Lipid Structure
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Saturated vs. Unsaturated
Animal fat
Vegetable oil
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What are trans fatty acids?
Carcinogenic
Natural
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(No Transcript)
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Cell Membrane
Phospholipid bilayer
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Steroids
Cholesterol
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VI. Proteins

• - the most abundant and varied of organic
  compounds
• - contain C, H, N, O (S)

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A. Types of protein

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

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

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B. Structure of Proteins

• - very complex
• - 3 basic shapes
• 1. helix (coil)
• 2. pleated sheet
• 3. globular

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Tertiary Protein Structure
Secondary Structure
Helix
Pleated Sheet
Random Coil
Tertiary Structure
Tertiary Structure
Globular
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1. Amino Acids

• - building blocks of proteins
• - 20 different amino acids
• - proteins contain between 50 - 2000 amino acids

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2. Peptide Bond

• - joins 2 amino acids
• - dipeptide 2 amino acids
• - polypeptide many amino acids

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Primary and Secondary Structure of Protein
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Peptide Bond
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C. Enzymes

• - protein catalysts
• - speed up chemical reactions
• - each enzyme catalyzes only one specific
  substrate
• - most function at a specific temperature and pH

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C. Enzymes
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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
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Information Flow
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The End
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Bonding Patterns of Common Atoms
Hydrogen
     
Carbon
Nitrogen
Oxygen
Phosphorus
Sulfur