Cellular Respiration
"How Cells Turn Food Into Energy"
Learning Objectives
By the end of this lesson, you will be able to:
Key Vocabulary
Glycolysis
The first step in cellular respiration where glucose is broken down in the cell’s cytoplasm to make energy.
Glucose
A simple sugar that is an important source of energy for cells.
Mitochondria
The part of the cell known as the 'powerhouse' where most energy is made.
What is Cellular Respiration?
Energy for Life
Every living thing needs energy to grow, move, and survive. Cellular respiration is the process cells use to turn food (like glucose) into usable energy.
Why It Matters
Without cellular respiration, your body wouldn’t have the energy to do anything—even breathe!
Stages of Cellular Respiration
1
Glycolysis
Glucose is broken down in the cytoplasm, making a little energy and smaller molecules.
2
Krebs Cycle
The smaller molecules enter the mitochondria and are broken down further, releasing more energy.
3
Electron Transport
Most energy is made here, and oxygen is used to help finish the process.
Where Does It Happen?
Inside the Cell
Most of cellular respiration takes place in the mitochondria, the cell’s 'powerhouse.'
Mitochondria use oxygen and glucose to make energy, water, and carbon dioxide.
Everyday Example: Exercise
Energy in Action
When you run, jump, or play sports, your muscles need lots of energy. Cellular respiration helps turn the food you eat into energy your muscles can use right away.
That’s why you breathe faster during exercise—to get more oxygen for your cells!
True or False and why? ✅ ❌ 🤔
Cellular respiration only happens when we are exercising because our bodies need extra energy then.
👍
TRUE
👎
FALSE
Now it's time to explain why...
True or False and why? ✅ ❌ 🤔
Cellular respiration only happens when we are exercising because our bodies need extra energy then.
👎
Why is that?
a) Cellular respiration is a continuous process that provides energy for all life functions, not just exercise.
b) Only the first stage of cellular respiration happens during exercise, the other stages happen all the time.
Answers on the next slide...
True or False and why? ✅ ❌ 🤔
Cellular respiration only happens when we are exercising because our bodies need extra energy then.
👎
✅
Why is that?
a) Cellular respiration is a continuous process that provides energy for all life functions, not just exercise. ✅
b) Only the first stage of cellular respiration happens during exercise, the other stages happen all the time.
Cellular Respiration vs. Photosynthesis
Cellular Respiration
Cells break down food and use oxygen to make energy.
Happens in animals and plants.
Photosynthesis
Plants use sunlight to make food from carbon dioxide and water.
Happens only in plants.
Summary: Energy for Life
Cellular respiration is how cells turn food into energy using oxygen. It happens in the mitochondria, and it’s why we need to eat and breathe. Understanding this process helps us see how our bodies and all living things stay active and alive.