Student Exploration: Cell Energy Cycle
Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes.
Vocabulary: aerobic, anaerobic, ATP, cellular respiration, chemical energy, chlorophyll, chloroplast,
cytoplasm, glucose, glycolysis, mitochondria, photosynthesis, radiant energy
Prior Knowledge Questions ( Do these BEFORE using the Gizmo.)
What does a plant need to survive and grow? In order to survive plants need water, soil, light, and Carbon Dioxide.
What does an animal need to survive and grow?
In order to survive animals need oxygen, food, water, and shelter.
- How do animals and plants depend on each other?
Plants provide animals with food and oxygen. Animals provide plants with carbon dioxide.
The Cell Energy Cycle Gizmo™ illustrates two processes that are
essential to life: photosynthesis and cellular respiration.
Although both of these processes involve a series of complex steps, the inputs and outputs of each process are four relatively simple molecules.
What is the chemical formula of oxygen?
Glucose is a simple sugar. What is the chemical formula of glucose?
- What is the chemical formula of carbon dioxide?
Name: Stephen Miller Date: 1
- What is the chemical formula of water?
Get the Gizmo ready:
● If necessary, click Reset. ● Check that the PHOTOSYNTHESIS tab is selected. Check that Description is turned on.
Introduction: Photosynthesis occurs in the chloroplas t , an organelle found in plant and algae cells.
Within the chloroplast, a green pigment called chlorophyll converts the radiant energy of
sunlight into chemical energy that the plant can use.
Question: What are the inputs and outputs of photosynthesis?
- Predict : Of the molecules shown on the MOLECULES pane, which do you think are inputs (ingredients) in photosynthesis? Which do you think are outputs?
Inputs: I think that Carbon Dioxide and Outputs: I think that Oxygen and Water are the inputs Glucose are the outputs.
- Explore : Drag each molecule from the MOLECULES pane to the chloroplast on the PHOTOSYNTHESIS
pane. If a molecule is an input, it will stay in the chloroplast.
- Observe : Click Add light and look at the Output. What are the outputs of photosynthesis?
Glucose and Oxygen are the products of photosynthesis.
- Summarize : Although photosynthesis is a complex process involving many reactions, it can be summarized by a simplified formula that shows inputs on the left and outputs on the right. Based on your observations, write a simplified formula for photosynthesis:
Which molecules are inputs in photosynthesis? Carbon Dioxide and Water
4. Observe : Click Next. What happens in the cytoplasm?
The Glucose molecule turns into two Pyruvic acid molecules.
This process is called glycolysis. Two pyruvate (C 3 H 3 O 3 – ) molecules are produced in glycolysis. The
released energy is used to form a net of two ATP ( adenosine triphosphate) molecules. Energy is later released when ATP molecules are broken down.
5. Observe : Click Next. What happens now?
The pyruvic acid molecules go into the mitochondrion.
6. Observe : Click Next. What happens in the mitochondrion?
Carbon Dioxide and Water are released. Along with a lot of energy.
Energy from the mitochondrion is also stored in the form of ATP. A net of 30 ATP molecules are produced for every two molecules of pyruvate.
7. Analyze : Cellular respiration involves two phases. The anaerobic phase does not involve oxygen,
while the aerobic phase does. Where does each phase take place?
Anaerobic: In the cytoplasm
Aerobic: In the mitochondrion. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
8. Summarize : Based on what you have seen, write a simplified formula for cellular respiration.
Which molecules are inputs in cellular respiraion? Glucose and Oxygen
- Challenge: To balance the inputs and outputs of cellular respiration, there should be the same number of
carbon, oxygen, and hydrogen atoms on each side of the arrow.
A. Is the formula balanced as written? Why or why not?
It is not balanced because there are more C, H, and O atoms on the left side of the equation.
B. Now balance the input/output formula by adding coefficients to each molecule. Write the balanced formula below, and then check your work by clicking Balance.
C6H1206 + 6 O2 6 CO2 + 6 H2O
- Compare : The aerobic phase of cellular respiration in the mitochondrion produces a net of about 28 to 30 ATP molecules. How does this compare to the energy released in glycolysis?
The aerobic phase produces a net of 28-30 ATP. Because there is more oxygen being used.
(Note: Some textbooks state that up to 36 ATP molecules are produced in this phase of cellular respiration. In reality, some energy is lost in the process due to the cost of transporting molecules and imperfect membranes.)
10.Extend your thinking : When you think of the word “respiration,” you might think about the process of breathing, which is actually called ventilation. (The respiratory system consists of the windpipe, lungs, etc.)
How is breathing related to cellular respiration? (Hint: Think about both the inputs and the outputs of cellular respiration.)
Breathing in allows us to take in oxygen, which is an input in cellular respiration. Breathing out is when we release carbon dioxide and sometimes water vapor. Which are outputs in cellular respiration.
The inputs of photosynthesis are the same as the outputs of respiration. The outputs of photosynthesis are the same as the inputs of respiration.
- Review : In photosynthesis and respiration, energy is converted from one form to another. Light is a form of
radiant energy. Glucose and ATP molecules store chemical energy.
A. During photosynthesis, what role is played by the radiant energy of the Sun? Explain your answer.
The energy from the sun is an input because it is used for photosynthesis but it is not made by photosynthesis.
B. In photosynthesis, what form of energy is sunlight converted to, and how is this energy stored? Photosynthesis changes radiant energy into chemical energy, which is stored in the glucose molecules.
C. Does cellular respiration result in a net input of energy or a net output of energy? Explain.
Energy acts as an output because energy is produced in respiration.
D. How is the energy produced by respiration stored?
The energy produced is stored as ATP molecules in respiration.
- Summarize : How are respiration and photosynthesis related to each other?
Respiration is the opposite of photosynthesis in that it uses oxygen and glucose to create energy, carbon dioxide, and water. While Photosynthesis uses carbon dioxide, water, and energy from the sun to create glucose and oxygen.
- Think and discuss : In what ways are plants and animals dependent on each other?
Animals need plants for food, oxygen, and shelter. Plants need animals for carbon dioxide and water.