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Valentina Aranyos
12/13/2025
AP Biology
Cellular Respiration
150
•
Dec 13, 2025
•
Cellular respiration is the crucial process that powers nearly everything... Show more
Ever wonder how your body gets energy to run, jump, or even think? It all comes from cellular respiration. This process breaks down glucose molecules to release the energy stored in their chemical bonds, which is then used to create ATP—the energy currency of all cells.
Cellular respiration comes in two main types. When oxygen is available, aerobic respiration occurs in three stages: glycolysis in the cytoplasm, followed by the Krebs Cycle and Electron Transport Chain in the mitochondria. Without oxygen, cells shift to anaerobic respiration, which includes glycolysis followed by fermentation, both happening in the cytoplasm.
The chemical equation for aerobic respiration looks like this: 6O₂ + C₆H₁₂O₆ → 6CO₂ + 6H₂O + Energy . This reaction releases a significant amount of free energy , which cells harness to power almost all their activities.
Did you know? Cellular respiration is one of the most conserved processes across all life forms, from bacteria to humans. This similarity suggests all living organisms share a common ancestor from billions of years ago!
Cellular respiration is basically a controlled burn happening inside your cells. It works through redox reactions, where some molecules lose electrons (oxidation) while others gain electrons (reduction).
During respiration, glucose gets oxidized - it loses electrons and energy. Meanwhile, other molecules like NAD+ and FAD get reduced by accepting those electrons, becoming NADH and FADH₂. Think of these as energy shuttle buses carrying electrons to where they're needed. Eventually, in aerobic respiration, oxygen acts as the final electron acceptor, combining with hydrogen to form water.
A handy way to remember this process is the acronym "OIL RIG": Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons). When something gets oxidized, it's giving up electrons; when it's reduced, it's receiving electrons.
Study Tip: The term "reduction" seems confusing until you realize it refers to reducing the positive charge of a molecule by adding negatively charged electrons to it!
Aerobic respiration is like a three-act play that extracts maximum energy from glucose. It starts with glycolysis in the cell's cytoplasm, where glucose is split into two pyruvate molecules. Every living organism on Earth can perform this process!
Next comes the Krebs Cycle (also called citric acid cycle), which happens in the mitochondrial matrix in eukaryotes or in the cytoplasm of bacteria. Here, those pyruvate molecules get completely oxidized, transferring their electrons to carriers like NAD+ and FAD, forming NADH and FADH₂. This step also produces a small amount of ATP directly.
Finally, the Electron Transport Chain occurs along the inner mitochondrial membrane (or cell membrane in bacteria). This is where the big energy payoff happens! The electron carriers deliver their electrons to a series of proteins, creating a proton gradient that drives ATP production. Oxygen serves as the final electron acceptor, combining with hydrogen to form water.
Energy Fact: The complete aerobic respiration of one glucose molecule can yield up to 38 ATP molecules—way more efficient than anaerobic processes which produce only 2 ATP!
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
App Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Cellular respiration is the crucial process that powers nearly everything your body does. It breaks down glucose (sugar) to release energy that cells can use, primarily in the form of ATP. This process is fundamental to all living organisms and... Show more
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Ever wonder how your body gets energy to run, jump, or even think? It all comes from cellular respiration. This process breaks down glucose molecules to release the energy stored in their chemical bonds, which is then used to create ATP—the energy currency of all cells.
Cellular respiration comes in two main types. When oxygen is available, aerobic respiration occurs in three stages: glycolysis in the cytoplasm, followed by the Krebs Cycle and Electron Transport Chain in the mitochondria. Without oxygen, cells shift to anaerobic respiration, which includes glycolysis followed by fermentation, both happening in the cytoplasm.
The chemical equation for aerobic respiration looks like this: 6O₂ + C₆H₁₂O₆ → 6CO₂ + 6H₂O + Energy . This reaction releases a significant amount of free energy , which cells harness to power almost all their activities.
Did you know? Cellular respiration is one of the most conserved processes across all life forms, from bacteria to humans. This similarity suggests all living organisms share a common ancestor from billions of years ago!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Cellular respiration is basically a controlled burn happening inside your cells. It works through redox reactions, where some molecules lose electrons (oxidation) while others gain electrons (reduction).
During respiration, glucose gets oxidized - it loses electrons and energy. Meanwhile, other molecules like NAD+ and FAD get reduced by accepting those electrons, becoming NADH and FADH₂. Think of these as energy shuttle buses carrying electrons to where they're needed. Eventually, in aerobic respiration, oxygen acts as the final electron acceptor, combining with hydrogen to form water.
A handy way to remember this process is the acronym "OIL RIG": Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons). When something gets oxidized, it's giving up electrons; when it's reduced, it's receiving electrons.
Study Tip: The term "reduction" seems confusing until you realize it refers to reducing the positive charge of a molecule by adding negatively charged electrons to it!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Aerobic respiration is like a three-act play that extracts maximum energy from glucose. It starts with glycolysis in the cell's cytoplasm, where glucose is split into two pyruvate molecules. Every living organism on Earth can perform this process!
Next comes the Krebs Cycle (also called citric acid cycle), which happens in the mitochondrial matrix in eukaryotes or in the cytoplasm of bacteria. Here, those pyruvate molecules get completely oxidized, transferring their electrons to carriers like NAD+ and FAD, forming NADH and FADH₂. This step also produces a small amount of ATP directly.
Finally, the Electron Transport Chain occurs along the inner mitochondrial membrane (or cell membrane in bacteria). This is where the big energy payoff happens! The electron carriers deliver their electrons to a series of proteins, creating a proton gradient that drives ATP production. Oxygen serves as the final electron acceptor, combining with hydrogen to form water.
Energy Fact: The complete aerobic respiration of one glucose molecule can yield up to 38 ATP molecules—way more efficient than anaerobic processes which produce only 2 ATP!
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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This document tackles blood and its types.
AP BiologyOverview of the key stages of cellular respiration, from glycolysis to oxidative phosphorylation, and the production of ATP.
AP BiologyAP Bio, Cellular Respiration- An Overview
AP BiologyA little study guide I made for my cellular respiration test in my bio class
AP BiologyThe citric acid cycle —also known as the Krebs cycle or the TCA cycle —is a series of chemical reactions to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins.
AP BiologyCovers metabolism for AP Biology 6.1
AP BiologyApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
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