Download Unit 1: The Chemistry of Life

Unit 1: The Chemistry of Life
Chapter 5
Macromolecules
Macromolecule theme
• Monomers
• Polymers
1. State the empirical formula for
carbohydrate. Explain what such a
formula means.
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(CH2O)n Carbons, Hydrogens, & Oxygens
Mostly we study the 6-carbons sugars
Rings, not chains
Recognize as dietary sugars, but have other
uses
2. To what do the terms monosaccharide,
disaccharide, and polysaccharide refer?
What do all three have in common?
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mono - one
di – two
oligo – several (mainly cell surfaces)
poly – many
All levels have the same empirical formula
(CH2O)n
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
• Metabolism = A + C
• Anabolism
• Catabolism
4. List the important differences
between starches and glycogen.
Where would each be found?
• Pg 72
• 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
5.
What is it that makes cellulose strong? How
is its strength further increased in plant fibers?
Its arrangement makes cellulose strong (pg73)
• 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 can’t digest any of
it, but it’s important to eat. Why?
- We don’t have the enzyme to break the linkage!
• How do cattle, deer, goats, etc. digest it?
– They house microorganisms to do it (4 stomachs)
6. What is the role of chitin and how is it
different from other carbohydrates?
Chitin=exoskeleton of insects & arthropods
• Very soft, but when combined w/ CaCO3,
becomes very hard
• Where does the CaCO3 come from?
Water
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.
8. Distinguish between an oil and a fat and between
a saturated fat, an unsaturated fat, and a
polyunsaturated fat. Are unsaturated fats more
common in animal tissue? Explain (pg75) .
• Oil  liquid at room temperature
• Fat  solid at room temperature
• Saturated  C-C single bonds, most H’s
– Ex. Lard, steak fat
• Unsaturated  C=C, fewer H’s
– Ex. Olive oil
• Polyunsaturated  many C=C’s
• Sat. Fat more common in animal tissue
– Need to be solid at normal temps!
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
By a diagram of a phospholipid bilayer, indicate the
hydrophobic and hydrophilic regions.
Extracellular water
Cytoplasm inside of cell
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 – that’s why they’re lipids!
• 4 linked carbon rings
Examples
• lanolin  sheep’s wool, human hair
• cholesterol  in cell membrane, sex hormones
– Allow flexibility in hair / membranes
Cholesterol
11. What are six significant uses for
proteins? (table 5.1)
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Enzymes  reactions
Energy  although not preferred
Immunity  antibodies
Structure / Support  muscle, tendon, etc.
Hormones  insulin, epinephrine, prolactin
Carriers  hemoglobin carries O2
12. Carefully define the term protein.
How is a protein different from a
polypeptide?
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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
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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Essential
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
Nonessential
Alanine
Asparagine
Aspartate
Cysteine
Glutamate
Glutamine
Glycine
Proline
Serine
Tyrosine
Arginine
Histidine
14. Describe the four levels of
organization possible in a protein,
and explain what forces are
involved at each level. (pg 82)
Primary  sequence of
amino acids
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sequence will
determine future
shape
Secondary
Secondary segments of the
polypeptide fold and coil in patterns
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alpha helices
beta sheets
What forces?
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H-Bonds
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
Tertiary
Quaternary
Quaternary  two or
more polypeptide
chains interacting
w/ each other
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same forces as
tertiary
15. How do collagen and hemoglobin differ
in reference to size, shape and function?
Collagen
Hemoglobin
Fibrous
Globular
Mostly helices
Beta sheet core
Small
Large (4 subunits)
Structural in function
Carrier molecule
Tendons, ligaments,
muscle coverings
In red blood cells –
carries O2
16. What is the process which links
two amino acids together?
Describe the reaction.
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Dehydration Synthesis
But you knew that!!!!
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
18. Identify the three types of
monomers found in a nucleotide.
• 5-carbon
sugar
• Phosphate
• Nitrogenous
base
• DNA & RNA