2 1 the Nature of Matter

Bio 392 Mrs. Van Ellis 2–4 Chemical Reactions and Enzymes Everything that happens in an organism—is based on ______A. Chemical Reactions Chemical reaction:

Reactants:

Products:

KEY CONCEPT:

What happens to chemical bonds during chemical reactions?

Write the 2 reactions in your book, and identify the reactants and products.

B. Energy in Reactions:

1. Energy Changes:

KEY CONCEPT:.

This is an example of:

What are the forms of energy that would be released in this reaction?

Is this a reaction that releases or absorbs energy?

The reverse reaction, in which water is changed into hydrogen and oxygen gas ..(finish statement)..

Thus, in one direction the reaction ______energy, and in the other direction the reaction ______energy.

In order to stay alive, organisms need to carry out reactions that______. Thus, every organism must have a source of ______to carry out ______.. How do organisms get energy?

2. Activation Energy:

Rewrite the caption for Figure 2-19 (below):

*Highlight or draw with a colored pencil the line showing activation energy. Circle the word reactant and put a star at the peak.

C. Enzymes (define): Catalyst:

KEY CONCEPT:

The activation energy barrier is like a wall between two parts of a pond. If an enzyme lowers the wall, more frogs have enough energy to reach the other side

Enzymes act by lowering the ______as illustrated by the graph below… Below, write the reaction in which carbon dioxide combines with water to produce carbonic acid.

What does the graph show would be the effect if enzymes were not available within a cell?

Would a reaction take longer or shorter with an enzyme? Enzymes are very specific, generally catalyzing ______chemical reaction. For this reason, part of an enzyme's name is usually derived from the reaction it catalyzes. Carbonic anhydrase gets its name because it catalyzes the reaction that removes water from carbonic acid.

D.Enzyme Action-

1. The Enzyme-Substrate Complex:(define)

substrates:

active site:

In Figure 2-21, what happens to the hexokinase after the products are released?

What are the substrates and the products in this reaction?

Using a key and padlock analogy, which is like the substrate and substrate?

2. Regulation of Enzyme Activity:

What happens after the substrate binds to the enzyme in Fig 2-22 in the book?

List some variables mentioned in your text, that can effect a chemical reaction.