Test Information
 Multiple Choice is Graded
 Test Review & Retake – Tuesday,
Wednesday or Thursday after school.
Monday, March 17, 2014
Happy St. Patrick’s Day!
Copy the title and the unit essential question. Use 2 pages – we’ll be
coming back to this many times.
Chemistry of Life.
How are chemical
reactions, energy, and
matter related in living
systems?
The Cracker
 Left side Warm-up: If you eat a cracker what will
occur in your body?
 List as much information as you know, the more
specific the better.
What are some chemical reactions going on in your
body or other living systems?
What are different types of molecules involved in
those reactions?
 (Hopefully you will know more in a few weeks!)
Title: Enzymes (right side)
 EQ: How are molecules built and broken
down?
Discuss: What are some chemical reactions
going on in your body or other living systems?
What are different types of molecules involved
in those reactions?
Examples
 dehydration synthesis (synthesis)
+
enzyme
H2O
 hydrolysis (digestion)
enzyme
H2O
+
Examples
 dehydration synthesis (synthesis)
enzyme
 hydrolysis (digestion)
enzyme
Enzymes
 Biological catalysts





proteins (& RNA)
facilitate chemical reactions
 increase rate of reaction without being
consumed
required for most biological reactions
highly specific
 thousands of different enzymes in cells
control reactions
of life
Enzymes vocabulary
substrate


reactant which binds to enzyme
enzyme-substrate complex: temporary association
product

end result of reaction
active site

enzyme’s catalytic site; substrate fits into active site
active site
substrate
enzyme
products
Properties of enzymes
 Reaction specific
 each enzyme works with a specific substrate

chemical fit between active site & substrate
 Not consumed in reaction
 single enzyme molecule can catalyze thousands or
more reactions per second

enzymes unaffected by the reaction
 Affected by cellular conditions
 any condition that affects protein structure

temperature, pH, salinity
Naming conventions
 Enzymes named for reaction they catalyze
 sucrase breaks down sucrose
 proteases break down proteins
 lipases break
down lipids
 DNA polymerase builds DNA
 adds nucleotides
to DNA strand
 pepsin breaks down
proteins (polypeptides)
Lock and Key model
 Simplistic model of enzyme
action


substrate fits into 3-D
structure of enzyme’ active
site
 H bonds between substrate
& enzyme
like “key fits into lock”
Size
doesn’t matter…
Shape matters!
Induced fit model
 More accurate model of enzyme action


3-D structure of enzyme fits substrate
substrate binding cause enzyme to change
shape leading to a tighter fit


“conformational change”
bring chemical groups in position to catalyze
reaction
Factors Affecting Enzyme Function
 Enzyme concentration
 Substrate concentration
 Temperature
 pH
 Salinity
 Activators
 Inhibitors
catalase
 Enzyme video
End of the Day
 Goal met?

In your journal write a paragraph: “Everything
I know so far about Enzymes” to help
consolidate your learning.
 Homework:
Question of the Day
http://kids.niehs.nih.gov
/illusion/illusions.htm
http://kids.niehs.nih.gov/braint11.htm