Cellular Respiration

Cellular Respiration

Middle School

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Learning Objectives

• Describe how body systems work together, to get resources to your cells.

• Explain cellular respiration, understand the requirements and its end products.

• Create a model showing how food provides energy, helps in the growth and repair.

• Understand that metabolism is the total of all chemical reactions in your body.

Key Vocabulary

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Metabolism

The sum of all chemical reactions in cells that convert food into energy for the body.

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Cellular Respiration

The chemical reaction inside cells where glucose and oxygen are changed into energy, water, and carbon dioxide.

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Glucose

A simple sugar molecule that is the main source of energy for cells through cellular respiration.

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Oxygen

A gas that is essential for cellular respiration to occur, brought into the body by the respiratory system.

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Amino Acid

The small molecules that are the building blocks of proteins, used for growth and tissue repair.

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Protein

Large molecules made of amino acids, essential for building and repairing body tissues like muscles.

Key Vocabulary

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Circulatory System

The body system that transports substances like oxygen to the cells and carries away waste.

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Respiratory System

The body system that takes in oxygen from the air and releases carbon dioxide.

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Digestive System

The body system that breaks down food into small molecules, like glucose, that can be absorbed.

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What Is Metabolism?

• Metabolism includes all chemical reactions in your body’s cells that keep you alive.

• Think of it as your body's engine, constantly running to keep you going.

• This process converts food into the energy needed for moving, thinking, and growing.

• Different body systems must work together for metabolism to happen effectively.

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Multiple Choice

What is metabolism?

• The process of breathing air in and out

• The circulation of blood throughout the body

• The chemical reactions in cells that keep the body alive

• The system that sends signals from the brain

Multiple Choice

What is the primary role of metabolism in the body?

• It helps the body to rest and fall asleep.

• It converts food into energy for the body to use.

• It makes the bones in the body stronger.

• It removes all waste products from the cells.

Multiple Choice

What would likely happen if one of the body systems involved in metabolism was not working correctly?

• The body would no longer need energy for thinking.

• The process of converting food to energy would be less effective.

• The body's cells would stop all chemical reactions instantly.

• Metabolism would speed up to make up for the problem.

Body Systems Working Together

• The digestive system breaks down food into simple sugars called glucose.

• Your respiratory system takes in the oxygen that your body needs.

• The circulatory system delivers oxygen and glucose to all your cells.

Multiple Choice

What is the main, combined purpose of the digestive, respiratory, and circulatory systems working together?

• To break down food into simple sugars called glucose.

• To take in the oxygen that the body needs to function.

• To deliver oxygen and glucose to all the body's cells.

• To turn food and air directly into muscle tissue.

Multiple Choice

What is the relationship between the digestive system and the circulatory system?

• The digestive system provides the oxygen that the circulatory system delivers.

• The digestive system provides the glucose that the circulatory system delivers.

• The circulatory system breaks down the food for the digestive system.

• The circulatory system provides the energy for the digestive system to work.

Multiple Choice

If a person's respiratory system stopped working correctly, what would be the most likely impact on the body's cells, even if the other systems were healthy?

• The body's cells would not get the glucose they need to function.

• The body's cells would not get the oxygen they need to function.

• The digestive system would stop breaking down food.

• The circulatory system would stop delivering glucose.

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Cellular Respiration: Releasing Energy

• Cellular respiration is a reaction that releases energy inside the cell’s mitochondria.

• ​It uses two key ingredients: glucose from food and oxygen from breathing.

• The process creates carbon dioxide, water, and vital energy for the cell.

• The equation is: Glucose + Oxygen → Carbon Dioxide + Water + Energy.

Multiple Choice

What is the main purpose of cellular respiration?

• To create glucose from sunlight

• To release energy for the cell to use

• To get rid of water in the cell

• To produce oxygen for the body

Multiple Choice

According to the chemical equation for cellular respiration, what materials are used by the cell to start the reaction?

• Carbon dioxide and water

• Water and energy

• Glucose and oxygen

• Carbon dioxide and glucose

Multiple Choice

If a cell's mitochondria could not get enough oxygen, what would be the most likely result?

• The cell would produce more glucose.

• The cell would produce less energy.

• The cell would release more oxygen.

• The cell would stop using water.

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Using Energy for Growth and Repair

• Your body uses energy from cellular respiration for growth and repair.

• ​Food provides amino acids, which are the building blocks of proteins.

• Energy is needed to combine amino acids to form larger proteins.

• This energy helps you build muscle and heal from injuries.

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Multiple Choice

What is the primary role of the energy your body gets from cellular respiration?

• For growth and repair

• To break down food into nutrients

• To remove waste from cells

• To make you feel warm

Multiple Choice

What is the relationship between energy, amino acids, and proteins?

• Energy is used to combine amino acids to form proteins.

• Amino acids are used to create energy for making proteins.

• Proteins are broken down by energy to release amino acids.

• Energy and proteins combine to create amino acids.

Multiple Choice

After a strenuous workout, an athlete eats a meal rich in protein. Which statement best explains how this meal helps their muscles?

• The body breaks the protein into amino acids and uses energy to rebuild muscle.

• The energy from the meal is directly converted into new muscle tissue.

• The amino acids in the meal are immediately used as an energy source.

• The protein is stored in the muscles to be used for energy later.

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Common Misconceptions

Misconception	Correction
Metabolism is just about burning calories for weight loss.	It includes all chemical reactions, like building muscle and storing energy.
The body creates energy from the food we eat.	Energy is released from food; it is not created.
Only food is needed to produce energy in the body.	Oxygen is also needed to release the energy from food efficiently.
Digestion and cellular respiration are the same process.	Digestion breaks down food. Cellular respiration uses that food to release energy.

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Summary

• Metabolism is the sum of all chemical reactions in the body that convert food to energy.

• The digestive, respiratory, and circulatory systems work together to deliver glucose and oxygen to every cell.

• Cellular respiration is the process where cells use glucose and oxygen to release energy, water, and carbon dioxide.

• The key equation for this process is: Glucose + Oxygen → Carbon Dioxide + Water + Energy.

Poll

On a scale of 1-4, how confident are you about explaining how food gives your body energy?

• 1 (Not confident at all)

• 2 (A little confident)

• 3 (Mostly confident)

• 4 (Very confident)