1' List the four major classes of biomolecules'

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1. List the four major classes of biomolecules.

• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids

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2. Explain how organic polymers contribute to
biological unity and diversity.

• Unity there are only 40 50 monomers used to
  make all macromolecules
• Diversity new properties emerge when these
  monomers are arranged in different waysleading
  to the diversity of life ?

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3. Describe how covalent linkages are formed
(condensation) and broken (hydrolysis) in organic
polymers.

• Condensation
• Polymerization reaction where monomers are
  covalently linked, removing a water molecule
• Remove H2O molecule

• Hydrolysis
• Reaction process that breaks covalent bonds
  between monomers by adding water molecules
• Add H2O molecule ?

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4. Explain how carbohydrates are classified.

• Carbohydrates are classified by the number of
  simple sugars
• They are organic molecules made of sugars and
  their polymers ?

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5. List four characteristics of sugar.

• An OH group is attached to each carbon except
  one, which is O
• 2. The size of the carbon skeleton varies from
  3-7 carbons
• 3. Spatial arrangement around asymmetric carbons
  may vary (ex enantiomers)
• 4. In aqueous solutions, many simple sugars form
  rings. (chemical equilibrium favors ring
  structures) ?

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6. Identify a glycosidic linkage and describe how
it is formed.

• Glycosidic linkage the covalent bond formed by
  a condensation reaction between 2 sugar monomers
• Sugar Sugar ? Big Sugar
• (monosaccharides) (glycosidic
  (disaccharide) ?
• linkage)

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7. Describe the important biological functions of
polysaccharides.

• Energy storage in the form of starch and
  glycogen
• 2. Structural support in the form of cellulose
  and chitin ?

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8. Distinguish between the glycosidic linkages
found in starch and cellulose.

• Starch
• Glucose monomers in a configuration
• -OH group is BELOW rings plane
• a 1-4 linkage

• Cellulose
• Glucose monomers in ß configuration
• -OH group is ABOVE rings plane
• ß 1-4 linkage ?

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9. Explain what distinguishes lipids from other
major classes of macromolecules.

• Lipids
• Are insoluble in water!
• Due to nonpolar C-H bonds
• Known as fats and oils ?

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10. Describe the unique properties, building
block molecules and biological importance of the
three important groups of lipids fats,
phospholipids and steroids.

• Fats made with glycerol, a 3 carbon alcohol and
  a fatty acid (carboxylic with a hydrocarbon tail)
• Used for
• Energy storage
• Compact fuel reserves
• Cushioning and insulating ?

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10. Continued.

• Phospholipids made with a glycerol, 2 fatty
  acids, a phosphate group, and a small chemical
  group
• Characteristics
• Tails are hydrophobic
• Will cluster in water
• Forms cell membrane bilayers ?

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10. Continued.

• Steroids are lipids that have 4 fused carbon
  rings with various functional groups attached
• Example
• Cholesterol
• - precursor to sex hormones and bile acids
• - common in cell membranes
• -atheriosclerosis ?

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11. Identify an ester linkage and describe how it
is formed.

• Ester linkage
• Bond formed between a hydroxyl group (-OH)
  and a carboxyl group (-COOH)
• Forms fat through condensation reactions that
  link glycerol to a fatty acid
• -OH -COOH ?

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12. Distinguish between saturated and unsaturated
fat, and list some unique emergent properties
that are a consequence of these structural
differences.

• Saturated Fats
• No double bonds between carbons in tail
• Has maximum number of hydrogens
• Solid at room temperature most animal fats
• C-C-C-C

• Unsaturated Fats
• One or more double bonds in tail
• Tail kinks at CC so molecules do not pack
  closely enough to solidify
• Liquid at room temperature most plant fats
• CC-CC ?

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13. Distinguish proteins from the other major
classes of macromolecules and explain the
biologically important functions of this group.

• Proteins a macromolecule that consists of one
  or more polypeptide chains folded and coiled into
  specific conformations
• Made up of various 20 amino acids
• Vary widely in structure and function
• Abundant about 50 of cellular dry weight
  (weight of cell minus water bulk) ?

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13. Continuedimportant functions

• Structural support
• 2. Storage of amino acids
• 3. Transport (hemoglobin)
• 4. Signaling (chemical messengers)
• 5. Cellular response to chemical stimuli
  (receptor proteins)
• 6. Movement (contractile proteins)
• 7. Defense against foreign substances
  disease-causing organisms (antibodies)
• 8. Catalysis of biochemical reactions (enzymes) ?

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14. List and recognize four major components of
an amino acid, and explain how amino acids may be
grouped according to the physical and chemical
properties of the side chains.

• Four components
• Hydrogen atom
• 2. Carboxyl group (-COOH)
• 3. Amino group (-NH2)
• 4. Variable R group (specific to each amino
  acid)
• - the properties of the side chain determine the
  uniqueness of each amino acid ?

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15. Identify a peptide bond and explain how it is
formed.

• Peptide bond the covalent bond formed by a
  condensation reaction that links the carboxyl
  (-COOH) group of one amino acid to the amino
  (-NH2) group of another.
• Bond between amino acids ?

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16. Explain what determines protein conformation
and why it is important.

• It is the 3D shape of a protein
• Enables a protein to recognize bind
  specifically to another molecule (ex hormone
  receptor)
• It is the consequence of the specific linear
  sequence of amino acids in the polypeptide
• Produced when new chains coil fold
  spontaneously (due to hydrophobic interactions)
• It is stabilized by chemical bonds weak
  interactions between neighboring regions of the
  folded protein ?

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17. Define primary structure and describe how it
may be deduced in the laboratory.

• It is the unique sequence of amino acids in a
  protein
• Determined by genes slight changes can affect
  function (ex sickle-cell)
• In a laboratory
• Determine amino acid composition by complete acid
  hydrolysis of peptide bonds identify the aas
  and proportions
• Determine the amino acid sequence by partial
  hydrolysis with enzymes and break specific
  peptide bonds deductively reconstruct from
  fragments
• Now automated sequencing ?

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18. Describe the two types of secondary protein
structure, and explain the role of hydrogen bonds
in maintaining the structure.

• Coiling folding of polypeptide backbone
• H bonds between peptide linkages in the proteins
  backbone help stabilize
• Alpha helix
• Helical coil stabilized by H bond every 4th
  peptide bond
• Found in fibrous protein collagen/elastin ?

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18. ContinuedBeta pleated sheet

• 2. Beta pleated sheet
• Sheet of antiparallel chains are folded into
  accordion pleats
• Held together by H bonds
• Dense core of globular proteins some fibrous
  protein ?

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19. Explain how weak interactions and disulfide
bridges contribute to tertiary protein structure.

• Weak Interactions
• Hydrogen bonding between polar side chains
• Ionic bonds between charged side chains
• Hydrophobic interactions between nonpolar in
  interior

• Covalent linkage
• Disulfide bridges between 2 cysteine monomers
  brought together by folding
• Reinforces conformation ?

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20. Using collagen and hemoglobin as examples,
describe quaternary protein structure.

• Collagen
• Fibrous protein with 3 helical polypeptides
  supercoiled into a triple helix

• Hemoglobin
• Four subunits grouped together (2 a chains and 2
  ß chains) ?

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21. Define denaturation and explain how proteins
may be denatured.

• Is the process that alters a proteins native
  conformation and biological activity
• Causes
• Transfer to an organic solvent-hydrophobic
  insides go out and vice versa
• Chemical agents that disrupt hydrogen, ionic, and
  disulfide bonds
• Excessive heat thermal agitation disrupts the
  weak interactions ?

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22. Describe the characteristics that distinguish
nucleic acids from the other major groups of
macromolecules.

• Nucleic acids
• Store and transmit hereditary information
• Are polymers of nucleotides
• Determine protein structure, function, etc.
• Examples
• RNA (ribonucleic acid)
• DNA (deoxyribonucleic acid) ?

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23. Summarize the functions of nucleic acids.

• To store and transmit hereditary information
• - directions for replication
• - information to run all cell activity
• - make up the genes for protein synthesis
• (the brain for making anything) ?

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24. List the 3 major components of a nucleotide,
and describe how these monomers are linked
together to form a nucleic acid.

• Pentose (5 carbon sugar)
• - ribose, deoxyribose
• 2. Phosphate attached to the 5th carbon of the
  sugar
• 3. Nitrogenous base pyrimidines purines
• Covalent bonds called phosphodiester linkages
  bond (between the phosphate of one sugar and the
  sugar of another) ?

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25. Distinguish between a pyrimidine and a purine.

• Pyrimidine
• six-membered ring made up of carbon and nitrogen
  atoms
• Ex cytosine (C)
• thymine (T) DNA
• uracil (U) RNA

• Purine
• five-membered ring fused to a six-membered ring
• Ex Adenine (A)
• Guanine (G)
• ?

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26. List the functions of nucleotides.

• Monomers for nucleic acids
• Transfer chemical energy from one molecule to
  another (ex ATP )
• Are electron acceptors in enzyme-controlled redox
  reactions of the cell (ex NAD) ?

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27. Briefly describe the three-dimensional
structure of DNA.

• Consists of 2 nucleotide chains wound in a double
  helix
• Sugar-phosphate backbones on the outside
• 2 strands held together by hydrogen bonds between
  the paired nitrogenous bases
• Van der waals attraction between stacked bases
• 2 DNA strands are complementary and serve as
  templates for new strands
• Long 1000s or millions of base pairs ?