Name ________________________________________________
Date _____
Cell Energy Lab
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Log on to www.explorelearning.com and launch: Cell Energy Cycle
Introduction
In 1977, scientists shocked the world with the announcement that they had discovered an
entirely new ecosystem, thriving around hot springs in the deepest recesses of the ocean. This was
stunning news because, until this discovery, it was thought that all life on Earth was dependent on the
sun as its ultimate source of energy. What scientists found were bacteria that can synthesize sugars
using energy from chemicals, like hydrogen sulfide, that are emitted from the hot springs.
The discovery was made in the Galapagos Rift, a deep trench in the eastern Pacific Ocean. The
conditions that exist around these vents are similar to those that likely existed on Earth early in its
development, billions of years ago. Therefore, some have suggested that these organisms may resemble
some of the earliest forms of life to appear on Earth.
Exploring Photosynthesis
In this activity, you will examine the molecules that play a role in the process of photosynthesis and
discover how the process creates an energy source that can support the functions of most of the Earth's
organisms.
1. In the Gizmo, be sure the PHOTOSYNTHESIS pane is visible. Click Reset to be sure the Gizmo is
reset to the beginning of the simulation. Drag the molecules from the CHEMICALS pane into the
cell.
a. Which molecules remain in this plant cell? ___________________ ________________
b. What cell structure do the chemicals come to rest on? ___________________
2. Notice that so far no additional chemical activity has occurred. Click Add light and observe the
results.
a. What are the outputs of photosynthesis? ___________________ ________________
b. Turn on Show formula of chemical equation. Click Balance and copy the equation below.
Exploring Cellular Respiration
In this activity, you will examine the process of cellular respiration. You may commonly think of
respiration as inhaling and exhaling. However, cellular respiration is the process of converting the
energy stored in the chemical bonds of glucose into molecules of adenosine triphosphate, or ATP, which
provide energy that cells can use directly.
1. Click the RESPIRATION tab and click Reset. Notice the mitochondrion displayed prominently in
the cell (an animal cell).
a.
Drag each of the molecules onto the cell. Which molecules enter the mitochondria
because they are reactants to the process of cell respiration?
__________________
b.
___________________
Click Next. What does the one glucose molecule turn into that remains in the cell?
______________________________________________________
2. This process is called glycolysis, literally meaning the "breaking of glucose." It occurs outside of
the mitochondria and does NOT require oxygen. Because it uses no oxygen, this is known as the
anaerobic stage of respiration.
a. What are the other products of this process that leave the cell?
__________________
______________________
3. Glycolysis produces a net gain of four molecules of ATP, which can be used by the cell as energy
for activities such as movement, protein synthesis, and cell division. Click on Next.
a. What organelle do the two molecules move into?
___________________________________________________
4. The next stage of cell respiration takes place here and DOES require oxygen. Because it requires
oxygen, this is referred to as the aerobic stage of respiration. Click on Next.
a. What are products from the aerobic stage of cell respiration?
____________________
_________________
________________
5. The process of cell respiration ultimately produces a net gain of 36 molecules of ATP from a
single molecule of glucose.
6. Turn on Show formula of chemical equation. Write the balanced equation below.
The Cycle of Photosynthesis and Cellular Respiration
In this activity, you will examine the relationship between cellular respiration and photosynthesis.
7. Click on the CYCLE tab and click Reset. Drag all the molecules to the CYCLE pane. Each molecule
is positioned with the process that uses it as an reactant.
a.
What are the reactant molecules for respiration?
_____________________________________________________
b.
What are the reactant molecules for photosynthesis?
______________________________________________________
8. Two processes form a cycle when the product from one process is the reactant for the other
process, and vice-versa.
a. Click on Balance equation and write the balanced equation below.
b. Explain how respiration and photosynthesis form a cycle by describing the origin and
destination of all four molecules.
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9. Take the quiz for bonus points.