Biology 12

Figure 2.19ATP therapy has great potential to help people

overcome diseases such as cancer.

Advantages of ATP

Within the cell, the use of ATP as a carrier of

energy is advantageous for several reasons:

1.ATP is the energy-rich molecule found in all

cells and is used in many different cellular

chemical reactions.

2.When ATP is broken down to ADP +Pi, some

of the energy released is used in reactions to

make more ATP.

3.ATP breakdown is coupled with endothermic

reactions in such a way that energy loss is

minimized. Some of the energy released is

used in endothermic reactions, such as protein

synthesis, muscle contraction, and nerve

conduction.

As you have learned, ATP is essential for the

endothermic and exothermic reactions that make

up the metabolic processes in all cells. In the next

chapter, you will study the two metabolic

processes common to life on Earth: cellular

respiration and photosynthesis. You will apply the

principles of thermodynamics and your knowledge

of enzymes to these essential metabolic processes.

Exothermic and endothermic reactions in cells

would not be possible without enzymes and ATP.

58 MHR • Unit 1 Metabolic Processes

SECTION REVIEW

1. Define the term “coupled reaction.”


2. How do coupled reactions work? In your
   explanation, include a diagram that demonstrates
   a coupled reaction.


3. What are the advantages of using the same
   energy source, ATP, in all cells?


4. Draw a diagram of ATP. Compose a paragraph
   detailing its structure and function.


5. ATP molecules have three main purposes in
   the cell. Aside from transport work such as the
   sodium-potassium pump, what are two examples
   of how ATP is used to do work in cells?


6. ATP scanners can be used to detect
   biochemical activity. The beef industry uses this
   technology to detect bacterial growth in meat.
   Describe another possible application of this
   technology in industry.
   7. How is chemical energy in an ATP molecule
   transformed into energy that can be used to do
   work? Explain your answer.
   8. How could you speed up a coupled reaction?
   Outline an experiment to test your hypothesis.

How can the energy from one reaction be used to fuel

another reaction? When designing your experiment for

the end-of-unit investigation, think about how reactions

are related and how some reactions are dependent on

other reactions.

UNIT INVESTIGATION PREP

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