1) A chemical reaction is a process that transforms one set of chemicals into another. Chemical reactions involve changes in chemical bonds and mass and energy are conserved. 2) Enzymes are specialized proteins that lower the activation energy of chemical reactions and allow reactions to occur easily up to 10 million times faster. Enzymes work by recognizing and binding to specific substrates in a lock and key fashion at their active sites. 3) Changes in temperature, pH, heavy metals or other chemicals can cause enzymes to denature or become inactivated so they are no longer the correct shape to function properly.

1. Chemical Reactions and Enzymes

2. Chemical Reactions and Enzymes
1) A ___________ ___________ is a process that changes,
chemical reaction
or transforms, one set of _____________ into another.
chemicals
2) Chemical reactions always involve changes in the
chemical _________ that join atoms in compounds.
bonds
*Mass and Energy are conserved during the reaction*

3. Chemical Reaction Examples
yields
i. CO2 + H2O  H2CO3
reactants products

4. Chemical Reactions
yields
ii. C6H12O6 + 6O2  6CO2 + 6H2O + Energy
reactants products
 The equation above shows how our cells get
energy from glucose

5. Chemical Reactions and Enzymes
release
3) Chemical reactions that _____________ energy often
occur spontaneously. Chemical reactions that
absorb
_____________energy will not occur without a source
of energy.
a) The burning of hydrogen gas with oxygen gas to produce
water is an energy __________________ reaction, while
releasing
absorbing
the electrolysis of water is an energy _______________
reaction.

6. Electrolysis of Water
2H2O(l) → 2H2(g) + O2 (g)

7. Chemical Reactions and Enzymes
a)Photosynthesis is a chemical
absorbs
reaction that ________energy in the
form of _______.
sunlight

8. Chemical Reactions and Enzymes
4) Signs that a chemical reaction has occurred include:
i. Formation of a precipitate (solid)
ii. Release of gas bubbles that are not due to a physical
change (boiling or sublimation)
iii. A color change
iv. A temperature change

9. Chemical Reactions and Enzymes
5)Sometimes reactions need a boost to get started. This
activation energy
boost is called the _____________ __________.
Example: Paper does not just burn spontaneously in the
presence of oxygen; rather, it needs a boost in the form
match
of a ________ to get started.

10. Chemical Reactions and Enzymes
5)Enzymes, also called _______, are
catalysts
specialized proteins in cells that lower
the activation energy so chemical
reactions can occur ____ without a
easily
huge boost (up to 10 million times
faster)!

11. Enzymes work by weakening bonds which lowers activation energy
Without Enzyme
With Enzyme
Free Activation Energy
Energy
Reactants
Products
Progress of the reaction

12. Steps in an enzyme reaction
a. Players:
Substrate – The molecule upon which an enzyme acts
Enzyme – Protein catalyst
Product – Final compound produced by the enzyme

13. Steps in an enzyme reaction
enzyme
1.The substrate meets up with the _________.
2.The substrate enters the enzyme at the point of
attachment called the active site
_________.
3.Once the substrates are in place, they form an
enzyme
_______/substrate complex. This interaction
stresses or weakens chemical bonds in the
substrates, thus lowering the activation energy.

14. Animation
Steps in an enzyme reaction
product
4. The newly formed _________ is released from
the active site.
conserve
5. The enzyme is _________ during a reaction
and ready to bedused again.

15. Chemical Reactions and Enzymes
8) Enzymes are
extremely _________
specific
for the substrates that
they accept. This is
similar to a lock and
key
_____.

16. Chemical Reactions and Enzymes
11) Enzymes can be “ _____________” (inactivated –
denatured
changed so that they are no longer the correct shape) by
temperature pH
drastic changes in ____________, ____, heavy metals,
or other ____________.
chemicals I contain bromelain –
an enzyme that
breaks down
protein !
Gelatin is made up of a
protein called collagen
Where does that's found in cow and
jello come pig hides, hooves,
from? bones, and connective
tissue.

18. Enzyme Activity Graph answers
a. At what temperature do most enzymes work best?
Most enzymes work best at 35oC (Body Temperature)
a. At what pH do most enzymes work best?
Most enzymes work best at pH of 7
a. Describe what happens to enzyme activity as more substrates are added.
Enzyme activity increases as substrate concentration increases to the point of
substrate saturation. It then levels off.