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Cellular Respiration: An Overview

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Learning Objectives

Identify how organisms get energy.
Explain how cellular respiration works.
Explain the relationship between photosynthesis and cellular respiration.

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Cellular Respiration

Cellular respiration is a process of energy conversion that releases energy from food in the presence of oxygen.

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Cellular Respiration

The chemical summary of cellular respiration is:

What does the equation look like expressed in symbols?

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Stages of Cellular Respiration

Glycolysis�
Krebs cycle�
Electron transport

Click to reveal the stages of cellular respiration.

Help students make the connection between this visual and the chemical summary equations from the previous slide.

Ask: Where are glucose and oxygen used during cellular respiration?

Answer: Glucose is the molecule that undergoes glycolysis. Oxygen is involved in electron transport.

Click to highlight glucose and oxygen.

Ask: Where do you see water, carbon dioxide, and energy in this diagram?

Answer: Carbon dioxide is released during the Krebs cycle. Water is released during electron transport. Energy is released at each stage.

Click to highlight water, carbon dioxide, and energy.

Explain to students that cellular respiration can be divided into three basic stages. Tell them that they will learn more detailed information about each of these stages in later lessons.

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Stage 1: Glycolysis

Glucose first enters a chemical pathway known as glycolysis. A small amount of energy is captured to produce ATP.

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Stage 2: Krebs Cycle

In the second stage of cellular respiration a little more energy is converted.

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Stage 3: Electron Transport

The final stage requires reactants from the other two stages of the process.

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Photosynthesis and Cellular Respiration

Photosynthesis and cellular �respiration can be thought �of as opposite processes.