Cellular Respiration
Cellular Respiration Objectives
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List the products of photosynthesis that are critical for human survival.
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Describe cellular respiration, including where it occurs in cells.
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Contrast cellular respiration with systemic respiration.
Humans have to consume other organisms as a source of energy and nutrients. We’re going to focus first on how cells convert sugar molecules into usable energy.
In the process of photosynthesis, plants, algae, and some bacteria can convert carbon dioxide and water in the presence of sunlight into sugar and oxygen. This primarily occurs in plant (or algae) chloroplast organelles.
They immediately use some of that sugar and oxygen to power cellular activity in the process of cellular respiration. This occurs in the mitochondria organelles.
Fortunately for us, plants (plus algae, and some bacteria) produce excess oxygen and have sugar in their bodies that we are able to consume.
Our own mitochondria also carry out cellular respiration; converting sugar and oxygen into usable ATP energy. Water that is produced is recycled by the cell for other uses. And carbon dioxide that is produced has to be eliminated by the body.
Respiration occurs in both plant and animal cells. In animals, tissues and organs are required to obtain the oxygen and sugar that plants can make for themselves.
This video provides an overview of cellular respiration.
Mitochondria in all complex-celled organisms, and chloroplasts in plants and algae, resemble free-living bacteria. The endosymbiotic theory states that mitochondria and chloroplasts in cells separately originated from one bacterial species engulfing (but not digesting) another.
The respiratory system is responsible for getting oxygen into the body and carbon dioxide out.
Multiple organ systems play a role in supporting cellular respiration:
Digestive System
Respiratory System
Cardiovascular System
Cellular Respiration: cells converting oxygen and sugar to ATP energy (and carbon dioxide and water).
Systemic Respiration: the process of breathing air in and out, the work done by the respiratory system.
The next section introduces the respiratory organs responsible for bring oxygen-rich air into the body and removing carbon dioxide.
Check your knowledge. Can you:
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list the products photosynthesis that are critical for human survival?
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describe cellular respiration, including where it occurs in cells?
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contrast cellular respiration with systemic respiration?
Go back to the Respiratory System Guide Overview
Go forward to the Respiratory Organ Page
Respiratory System Lecture Guide Contents
The material from this guide and corresponding lecture is assessed on the weekly quiz.
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