Molecules of Life
What comes to mind when you
hear or see the word organic?
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Most “life” molecules have a backbone of
carbon.
Carbon can form 4 bonds so many atoms can
bond and branch off.
With a partner, determine
what kind of bond you
see in this illustration
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Many molecules are composed mostly of
carbon & hydrogen = Hydrocarbons
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Biomolecules may be made of hundreds to
millions of atoms!
Large molecules are built from smaller,
repeating units.
Small molecular units that make up a
Monomer =
polymer.
Polymer = Long chains of monomers.
Carbohydrates
Lipids
Nucleic Acids
Proteins
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What does the word “organic mean”?
List the four categories of organic molecules?
STRUCTURE:
Hydrogen, Oxygen and Carbon
-Monomer: Monosaccharides
These are simple sugars.
-When you put monosaccharides together,
you get: Polysaccharide
- A key source of energy for cells and the body.
Examples of Carbohydrates:
 Starch – energy in plants
 Glycogen – energy in animals
 Cellulose – structural support in plants
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What is the function of a carbohydrate?
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Give 2 food examples of carbohydrates.
What are the three structural examples of
carbohydrates?
Starch
Glycogen
Cellulose
Answer the questions on
the starch lab and hand in
before leaving class
Structure
-Monomers: Glycerol & Fatty Acids
-Polymer: Fat
They are hydrophobic – “water fearing”
Function: To Store Energy
◦ Saturated Fat – all fatty acid chains contain
max of hydrogen atoms (all single bonds).
◦ Solid at room
temperature.
◦ Contribute to
an unhealthy
diet.
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Unsaturated Fats – contain less than the
maximum number of hydrogen atoms in the
fatty acid chains.
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Liquid at room temp.
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Healthier choice.
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Example:
◦ Testosterone
(male hormone)
◦ Estrogen
(female hormone)
◦ Cholesterol
STRUCTURE
 Made of Amino Acids
Function
Building blocks for parts of
the body
Examples
◦ Body Structures: Hair, Fur, Nails, Muscle.
◦ Long Term Nutrient Storage.
◦ Body Defense – Receptors on Cells
◦ Control Chemical Reactions
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Watch enzyme animations:
http://www.youtube.com/watch?v=XTUm75-PL4&feature=related
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Used to speed up chemical reactions in a cell.
(lowers the amount of energy needed)
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End in “ase”
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Protease breaks down proteins
Lipase breaks down fats
Enzymes are catalysts:
Speeds up reaction, can be used over and over
again. The reaction does not change it (like a
key!)
Acts on a substrate:
The substance that is changed during the
reaction.
 An
enzyme lowers the energy needed so that
the reaction can work at normal cell
temperatures
How an Enzyme Works:
 Shape of an enzyme only fits particular
molecules (substrate)
 Active site → where the substrate fits
Cut the two different colors of paper into
interlocking puzzle pieces.
 Label one color ENZYME (Amylase)
Label the other SUBSTRATE (Cracker)
 On the enzyme, label the point at which the it
locks into the substrate = ACTIVE SITE
 Cut out a small chunk of paper out of the
substrate where it touches the active site of
the enzyme. Label the little piece = e At point of missing e-, cut the substrate in
half.
 Push the enzyme into the substrate to split
the products!
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1. What is being
broken down?
2. Where the two
parts meet?
3. What is doing
the breaking?
4. What three things affect how well an enzymatic reactions occurs?
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Visualize that our classroom is now a cell,
and you are either an enzyme (key) or a
substance to be broken down called a
substrate (lock).
Quick Write: How does this activity help to
represent the role of enzymes?
-What does the lock represent?
-What does the key represent?
-Where is the active site?
_What is the general steps that occur when a
substrate is broken down by an enzyme?