Cellular Respiration is a catabolic reaction that takes place in the mitochondria and is a process that releases energy in food with the presence of oxygen (aerobic). There are three stages of cellular respiration: Glycolysis, the Krebs Cycle, and the Electron Transport Chain.
"In stage one, glucose is broken down in the cytoplasm of the cell in a process called glycolysis."
- First step in both cellular respiration and fermentation
- Occurs in both aerobic (with oxygen) & anaerobic (without oxygen) pathways
- It takes place in the cytoplasm
- It occurs in all living things (prokaryote & eukaryote)
- Glycose -> Pyruvic acid
- C6H12O6 -> 2C3H4O3
- A net of 2 ATP are made
- 2 NADH are made
Krebs Cycle (Citric Acid Cycle)
"The mitochondria are the organelles known as the energy "powerhouses" of the cells. In the mitochondria, the pyruvate, which have been converted into a 2-carbon molecule, enter the Krebs cycle. Notice that mitochondria have an inner membrane with many folds, called cristae. These cristae greatly increase the membrane surface area where many of the cellular respiration reactions take place."
- Second step in cellular respiration
- Takes place in matrix of mitochondria
- Pyruvic acid is broken down into carbon dioxide
- More NADH are made
- FADH2 are made
- Releases 2 more ATP
Electron Transport Chain
"In stage three, the energy in the energy carriers enters an electron transport chain. During this step, this energy is used to produce 34 ATP."
- Also known as oxidative phosphorylation
- Occurs in the cristae of the mitochondria
- NADH & FADH2 are used
- High energy electrons that come from krebs cycle are used to convert ADP into ATP
- Oxygen is a reactant & water is a product
Importance of cellular respiration from a local & global perspective:
Local & Global: Breathing is directly related to cellular respiration because it provides the oxygen molecules for the process to take place. All living organisms contribute to this process. Respiration also removes toxic carbon dioxide from our systems. This process provides the energy for all living organisms to perform all of the necessary functions in life
- "Cellular Respiration." Biology Laboratory Manual | Cellular Respiration. McGraw Hill Online Learning Center, 2017. Web. 23 Jan. 2017. <https://highered.mheducation.com/sites/0073031216/student_view0/exercise11/cellular_respiration.html>.
- Harwood, Jessica, Ph.D. Douglas Wilkin, Ph.D. Doris Kraus, Niamh Gray-Wilson, Ph.D. Jean Brainard, Sarah Johnson, Jane Willan, and Corliss Karasov. "Process of Cellular Respiration." CK-12 Foundation. CK-12 Foundation, 30 Aug. 2016. Web. 23 Jan. 2017. <http://www.ck12.org/book/CK-12-Life-Science-Concepts-For-Middle-School/section/2.14/>.
- Potter. "Cellular Respiration." Cellular Respiration. N.p., n.d. Web. 23 Jan. 2017. <https://msu.edu/~potters6/te801/Biology/biounits/respiration.htm>.