Water

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Water
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The Nature of Water - H2O

• Exists in three forms (gas, liquid and solid)
• Makes up approx 90 of organisms
• Versatile Solvent
• Important in the cells chemistry
• Gains and releases heat slowly
• High surface tension
• A polar molecule
• 2 small hydrogen atoms
• 1 large oxygen atom

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2-3 Carbon Compounds

• Compounds that contain CARBON are called organic.
• Carbon has 4 electrons in outer shell.
• Carbon can form covalent bonds with as many as 4
  other atoms (elements).
• Usually with C, H, O or N.
• Example CH4(methane)

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• 25 naturally occurring elements are essential for
  life. Carbon, hydrogen, oxygen and nitrogen (C,
  H, O, N) make up 96 of living matter.
• The remaining 4 is composed of seven elements
  (Ca, P, K, S, Na, Cl, Mg). Some elements, like
  iron (Fe) and iodine (I) may be required in very
  minute quantities and are called trace elements.

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Biological Macromolecules
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Macromolecules

• Large organic molecules.
• Also called POLYMERS.
• Made up of smaller building blocks called
  MONOMERS.
• The monomers in a polymer may be identical or
  they may be different. Some of the molecules
  that serve as monomers also have other functions
  on their own.
• Examples
• 1. Carbohydrates
• 2. Lipids
• 3. Proteins
• 4. Nucleic acids (DNA and RNA)

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Carbon the backbone of organic macromolecules!
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Carbon the backbone of organic macromolecules!
Single bond
Double bond
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Polymerization

• The process of stringing together monomers to
  make polymers is called polymerization (or
  dehydration synthesis).
• Monomers are connected by a reaction in which two
  molecules are covalently bonded to each other
  through the loss of a water molecule.
• Each monomer contributes part of the water
  molecule that is lost one molecule provides the
  OH, while the other provides the hydrogen (H).

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Hydrolysis

• Polymers are disassembled to monomers by
  hydrolysis (from the Greek word hydro meaning
  water and lysis meaning to split.)
• In hydrolysis, polymers are split by water in a
  process that is essentially the reverse of
  dehydration synthesis.
• Bonds between monomers are broken by the addition
  of water molecules, a hydrogen from water
  attaching to one monomer and an OH attaching to
  the adjacent monomer.

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Animation

• Animation of Dehydration Synthesis and Hydrolysis

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Carbohydrates

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The Nature of Carbohydrates

• Recognized by the formula (CH2O)n
• 121
• Grouped into mono-, di-, and polysaccharides
• Important as
• A quick energy nutrient - glucose
• Serve as a storage of energy - glycogen (animals)
  and starch (plants)
• Structural significance chitin of Arthropods
  and fungus and cellulose of plants

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product of photosynthesis Milk sugar beets
fruit
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Common Disaccharides

• Sucrose (glucose fructose)
• Found in plant like sugar cane, sugar beets
• table sugar
• Maltose (glucose glucose)
• Found in germinating grain
• Lactose (glucose galactose)
• Found in the milk of mammals

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Polysaccharides

• Cellulose Structural component of plants
  (cell walls lettuce, corn, some protists)
• Starch storage of energy in plants
  (bread, potatoes, rice)
• Glycogen storage of energy in animals
  (beef muscle)
• Chitin structural component of arthropods
  (roaches, crickets)

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Lipids
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The Nature of Lipids

• Lipids are one class of biological macromolecules
  that does not include polymers.
• The lipids are grouped together because they are
  not soluble in water.
• Lipids are a highly varied group in form and
  function.

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• Highest source of energy thats why our extra
  energy is stored as fat in fat tissue
• Also important as
• structural components of cells (membranes)
• Chemical messengers - hormones (steroids)
• protective waxes (earwax, outer covering of
  insects)
• Protection against heat loss (insulation)

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Examples of Lipids

• General term for compounds which are not soluble
  in water.
• Lipids are soluble in hydrophobic solvents.
• Remember stores the most energy
• Examples
• 1. Fats
• 2. Phospholipids
• 3. Oils
• 4. Waxes
• 5. Steroid hormones
• 6. Triglycerides

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Fats

• (long-term energy storage )
• Cushions organs
• insulation

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• Two types of molecules used to make a fat
• Glycerol (three carbon molecule)
• Fatty acids (long hydrocarbon chain, usually
  16-18 carbons atoms in length) that is
  hydrophobic (does not dissolve in water).

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What Does Fat Look Like?
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The Letter E
Glycerol
E
Fatty Acids
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Saturated vs. Unsaturated Fats

• Unsaturated Fats
• Liquid at room temp.
• Yellow in color
• Derived from plants
• Some double bonds between carbons
• Fatty acids crooked
• Examples include corn, canola, and olive oils
• BETTER (healthier)

• Saturated Fats
• Solid at room temp.
• White in color
• Derived from animals
• No double bonds between carbons
• Fatty acids straight
• Examples are the hard fats (lard)
• BAD (unhealthy)

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Polyunsaturated

• Many carbon-carbon double bonds
• Liquid at room temperature
• Cooking oils corn, sesame, peanut, canola, olive
• BEST (healthiest) because they do not collect in
  your blood vessels and cause plaque.

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Phospholipids

• Phospholipids are a major component of cell
  membranes.
• The cell membrane regulates what enters and
  leaves the cell and provides protection and
  support.
• Phospholipids are similar to fats but they only
  have two fatty acid tails, instead of three,
  attached to a glycerol molecule.

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• A phospholipid has a hydrophilic head that wants
  to interact with water and two fatty acid tails
  that are hydrophobic and are repelled by water.

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Steroids

• Steroids are lipids characterized by a carbon
  skeleton consisting of four fused rings.

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• One steroid, cholesterol, is a common component
  of animal cell membranes and is the precursor
  from which other steroids are synthesized.
• Too much cholesterol in the blood may contribute
  to heart disease.
• About 10 of people ages 12 to 19 have blood
  cholesterol levels, which put them at risk later
  in life for developing heart disease the
  leading cause of death in the United States.

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• Hormones are chemicals released in one part of
  the body that travel through the bloodstream and
  affect the activities of cells in other parts of
  the body.
• They do this by binding to specific chemical
  receptors on target cells. If a cell does not
  have receptors, the hormone has no effect.

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Proteins
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The Nature of Proteins

• Elements N, C, H, O
• Made of units called amino acids (only 20)
• Twenty Amino acids combine in different ways to
  make, perhaps, 100,000 different proteins!
• Amino acids link together by peptide bonds
• Makes polypeptides

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Six functions of proteins

• 1. Storage albumin (egg white)
• 2. Transport hemoglobin
• 3. Regulatory hormones
• 4. Movement muscles
• 5. Structural membranes, hair, nails, bones
• 6. Enzymes cellular reactions

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Proteins (Polypeptides)

• Four levels of protein structure
• A. Primary Structure (1)
• B. Secondary Structure (2)
• C. Tertiary Structure (3)
• D. Quaternary Structure (4)

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A. Primary Structure (1)

• Amino acids bonded together by peptide bonds.

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B. Secondary Structure (2)

• 3-dimensional folding arrangement of a primary
  structure into coils and pleats held together by
  hydrogen bonds.
• Two examples

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C. Tertiary Structure (3)

• Secondary structures bent and folded into a more
  complex 3-D arrangement.
• Bonds H-bonds, ionic
• Called a subunit.

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D. Quaternary Structure (4)

• Composed of 2 or more subunits.
• Example enzymes, hemoglobin

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Enzymes

• Acts as catalysts
• Speed up a chemical reaction
• Lower activation energy
• Needed to start a reaction
• Specific
• Act on a substrate

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Enzyme Action
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Denaturation
Denaturation of proteins involves the disruption
and possible destruction of both the secondary
and tertiary structures. Usually caused by
acids, bases, heat, alcohol
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Nucleic Acids
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The Nature of Nucleic Acids

• Two types DNA and RNA
• Composed of units called nucleotides
• Phosphate molecule
• 5 carbon sugar
• organic base (a purine or pyrimidine)
• May be double or single-stranded
• Single strands united by base-pairing

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Organic (Nitrogenous) Bases
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Importance of Nucleic Acids

• Insure genetic continuity from one cell
  generation to the next
• Directs the production of proteins at the
  ribosome construction site in the cytoplasm

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