Download Chemical Reactions and Enzymes

Chemical Reactions and Enzymes (Chapter 2.4)
Pages 50-53
Chemical Reactions
 A chemical reaction is the process that

The elements or compounds that enter a chemical reaction are known as ___________________ and
the result is the formation of a _______________________.

Chemical reactions always involve changes in the _______________ ______________ that join atoms
in compounds.
Fill in the blanks using Figure 2-19 as a guide:
When your body uses energy, carbon dioxide (CO2) is made as a waste product. It enters your blood
stream and reacts with ______________ to produce carbonic acid (H2CO3). This reaction allows blood to
carry carbon dioxide to your ____________. Once it reaches your lungs, the reaction happens in reverse,
so the carbon dioxide can be _______________.
The equation looks like:
CO2 + H2O  H2CO3
What is/are the reactants of this reaction? ________________
What is/are the products of this reaction? ________________
Energy in Reactions
 Energy is __________________ or ____________________ whenever chemical bonds are formed or
broken.

Chemical reactions that release energy often occur _____________________________________.

Chemical reactions that absorb energy will not occur without ______________________________.
During photosynthesis, plants use sunlight to make an energy source carbohydrate called glucose. Do
the chemical reactions that occur during photosynthesis release or absorb energy? _______________
After you eat, your body performs chemical reactions called cellular respiration to break up the glucose.
You use the energy for movement. Are the reactions of cellular respiration releasing or absorbing
energy? ______________________

Activation energy is the amount of energy that is ________________________________________.
Enzymes
 Enzymes are _________________ that act as ____________________________________________.

Enzymes ___________________________ chemical reactions that take place in cells.

Like other catalysts, enzymes work by ___________________ the activation energy. This drastically
effects how quickly a reaction can happen.

If the reaction CO2 + H2O  H2CO3 was left to itself, it would occur so slow that carbon dioxide would
_______________________ in the body, faster than the bloodstream could remove it. Thus, your
blood contains the enzyme ______________________________ that speeds up the reaction by a
factor of ____________________.

Use Figure 2-21 to complete the matching
Answer with the letter labeled in the picture.
1) The activation energy required without an
enzyme. ______
Energy 
2) The amount of energy in the products. _____
3) The amount of energy release from the
reaction. ______
4) The activation energy when an enzyme is
used. ______
Course of Reaction 
5) The amount of energy in the reactants. ______

Enzymes are very _________________ and generally only work for one chemical reaction.

Define substrate:
Look at figure 2-22.
What are the substrates of the enzyme carbonic anhydrase? _________________________
What is the name for the area on the enzyme where the substrates bind? ______________________
What happens to the enzyme after it releases the products? _________________________
Regulation of enzymes
What are two environmental conditions that can affect the activity of enzymes?