Unit 1: The Chemistry of Life

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Unit 1 The Chemistry of Life

• Chapter 5
• Macromolecules

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Macromolecule theme

• Monomers
• Polymers

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1. State the empirical formula for a
carbohydrate. Explain what such a formula means.

• (CH2O)n Carbon, Hydrogen, Oxygen
• Mostly we study the 6-carbons sugars
• Rings, not chains
• Recognize as dietary sugars, but have other uses

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2. To what do the terms monosaccharide,
disaccharide, and polysaccharide refer? What do
all three have in common?

• mono - one
• di two
• oligo several (mainly cell surfaces)
• poly many
• All levels have the same formula (CH2O)n

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3. Explain what is meant by dehydration
synthesis. What is the opposite process called?
How are both important to most biological
molecules?

• Dehydration loss of water synthesis to make
• Make a molecule by dehydrating it
• Hydro water Lysis to break apart
• Using water to break apart molecules
• Both require specific enzymes
• To live, we must build up molecules, and tear
  molecules down
• EX Eating carbos / waking up

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4. List the important differences between
starches and glycogen. Where would each be found?

• Starches ? string of glucoses
• somewhat branched
• form storage granules in PLANTS
• Glycogen? string of glucoses
• highly branched
• energy storage for animals (Fungi too)
• found in the liver muscles

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5. What is it that makes cellulose strong? How
is its strength further increased in plant fibers?

• Its arrangement makes cellulose strong
• Beta linkages create a sturdy, rigid structure
• Hydrogen bonding then forms long, microfibrils
  like a suspension bridge
• Forms sturdy cell walls in plants
• Cellulose is dietary fiber we cant digest
  any of it, but its important to eat. Why?
• - We dont have the enzyme to break the linkage!
• How do cattle, deer, goats, etc. digest it?
• They house microorganisms to do it (4 stomachs)

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6. What is the role of chitin and how is it
different from other carbohydrates?

• Chitinexoskeleton of insects arthropods
• Very soft, but when combined w/ CaCO3, becomes
  very hard
• Where does the CaCO3 come from?
• Water

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• 7. List the essential parts of a triglyceride.
• 1 glycerol and 3 fatty acid molecules
• Through what enzymatic process are triglycerides
  joined?
• Dehydration synthesis
• What makes one triglyceride differ from the
  next?
• Length of fatty acid chain, degree of saturation
• Which end of the triglyceride is more
  hydrophobic?
• The long chain portion.

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8. Distinguish between an oil and a fat and
between a saturated fat, an unsaturated fat, and
apolyunsaturated fat. Are unsaturated fats more
common in animal tissue? Explain.

• Oil ? liquid at room temperature
• Fat ? solid at room temperature
• Saturated ? C-C single bonds, most Hs
• Ex. Lard, steak fat
• Unsaturated ? CC, fewer Hs
• Ex. Olive oil
• Polyunsaturated ? many CCs
• Sat. Fat more common in animal tissue
• Need to be solid at normal temps!

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9. Describe the general structure of
phospholipids, and explain their arrangement into
membranes.

• Phosphate head (Hydrophilic)
• 2 fatty acid chain tails (Hydrophobic)
• One is saturated, one is not

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By a diagram of a phospholipid bilayer, indicate
the hydrophobic and hydrophilic regions.
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10. List the special uses of steroids. How do
steroids differ structurally from other lipids?

• Steroids ? structurally different from fatty
  acids or lipids
• They hate water thats why theyre lipids!
• 4 linked carbon rings
• Examples
• lanolin ? sheeps wool, human hair
• cholesterol ? in cell membrane, sex hormones
• Allow flexibility in hair / membranes

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Cholesterol
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11. What are six significant uses for proteins?

• Enzymes ? reactions
• Energy ? although not preferred
• Immunity ? antibodies
• Structure / Support ? muscle, tendon, etc.
• Hormones ? insulin, epinephrine, prolactin
• Carriers ? hemoglobin carries O2

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12. Carefully define the term protein. How is a
protein different from a polypeptide?

• Proteins? large, complex molecules made up of
  amino acids joined by dehydration synthesis
  reactions
• Polypeptide ?a string of A.A.s
• transported in blood like this
• cells take p.p.s in and utilize the A.A.s

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13. What do all amino acids have in common? How
do they differ?

• Each A.A. has a carbon with four groups
• amine group (NH2)
• carboxyl group (COOH)
• Hydrogen
• R group

How many A.A.s? How many are essential?
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14. Describe the four levels of organization
possible in a protein, and explain what forces
are involved at each level.

• Primary ? sequence of amino acids
• sequence will determine future shape

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Secondary

• Secondary? segments of the polypeptide fold and
  coil in patterns
• alpha helices
• beta sheets
• What forces?
• H-Bonds

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Tertiary

• Tertiary? bends and twists cause a three
  dimensional shape. Why?
• a. nonpolar R groups group together away from
  the polypeptide
• b. H-bonds can form between polar R groups
• c. 2 sulfhydryl groups can form a disulfide
  bridge
• d. charged R groups can attract or repel

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Quaternary

• Quaternary ? two or more polypeptide chains
  interacting w/ each other
• same forces as tertiary

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15. How do collagen and hemoglobin differ in
reference to size, shape and function?
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16. What is the process which links two amino
acids together? Describe the reaction.

• Dehydration Synthesis
• But you knew that!!!!

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17. What is denaturation? How or when may it
occur? What does a protein lose when it becomes
denatured?

• Denaturation? when a protein unravels or loses
  its shape (becomes inactive)
• -normally a polypeptide will spontaneously
  arrange itself, however
• Changes in
• pH
• salt concentration
• temperature
• other environmental aspects

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18. Identify the three types of monomers found in
a nucleotide.

• 5-carbon sugar
• Phosphate
• Nitrogenous base
• DNA RNA

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19. Name which nitrogenous bases are purines.
Pyrimidines?

• Purines Adenosine (A) Guanine (G)
• Pyrimidines Cytosine (C) Thymine (T)
• Hint? Y do you ask?

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20. How are purines and pyrimidines linked in a
double helix? Which ones attach to which?

• Linked by hydrogen bonds
• A T
• G C

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Whats the monomer or polymer in..

• Cellulose
• A polypeptide
• DNA
• Glucose
• Sucrose
• Amino acid
• Trigylceride
• Starch
• Cholesterol