Anaerobic Respiration

Summary

In this video, Bozeman Science dives into the fascinating world of anaerobic cellular respiration. Mr. Anderson clarifies how cells produce energy when oxygen is scarce or mitochondria aren't available. He compares aerobic and anaerobic processes, emphasizing glycolysis and introducing fermentation. Lactic acid and alcoholic fermentation are discussed as clever evolutionary hacks our bodies employ to keep generating ATP when oxygen is low, albeit less efficiently. We explore how these systems work in both humans and microbes, unraveling why our muscles ache during sprints and how fermentation creates beloved beverages like wine and beer.

Highlights

• Anaerobic respiration serves as a backup plan when oxygen runs low in our bodies! 🤯
• Glycolysis is the starting point for both aerobic and anaerobic respiration, setting the stage for energy production. 🚀
• Fermentation allows organisms to continue glycolysis when oxygen is unavailable, using either lactic acid or alcohol fermentation. 🍷
• Muscle pain during intense exercise is often due to lactic acid buildup, a byproduct of anaerobic energy production. 🏋️‍♀️
• Fermentation isn't just a scientific process—it's why we have delicious foods and drinks like yogurt and beer! 🍻

Key Takeaways

• Anaerobic respiration kicks in when oxygen is low or mitochondria are absent, allowing cells to produce energy without oxygen. 🏃‍♂️
• Glycolysis is the initial step in both aerobic and anaerobic respiration, breaking down glucose into pyruvate. 🔄
• Lactic acid fermentation happens in animals and some bacteria, turning pyruvate into lactate, crucial in intense exercise and certain food production. 🐄🍦
• Alcoholic fermentation occurs in yeast, transforming pyruvate into ethyl alcohol and carbon dioxide, used in brewing and baking. 🍺🥖
• Anaerobic respiration is less efficient than aerobic respiration but crucial for short bursts of energy and survival in low-oxygen environments! ⚡️

Overview

Anaerobic cellular respiration is an alternative energy production process that kicks in when oxygen levels are too low for aerobic respiration. Starting with glycolysis, this process breaks down glucose into pyruvate, yielding 2 ATP molecules. However, when oxygen is unavailable to accept electrons at the end of this chain, our cells employ fermentation to keep glycolysis running!

In the absence of oxygen, humans rely on lactic acid fermentation, which converts pyruvate into lactate, allowing glycolysis, and thus ATP production, to continue. This process, while less efficient than aerobic respiration, provides a quick energy boost during intense physical activities. It's the reason behind the burning sensation in our muscles during a sprint.

Yeast and some bacteria use alcoholic fermentation, transforming pyruvate into ethyl alcohol and carbon dioxide. This method has been utilized for thousands of years in producing alcohol and bread. Although less productive in terms of energy yield, anaerobic respiration is a crucial evolutionary adaptation, ensuring survival in diverse environments.

Chapters

• 00:00 - 00:30: Introduction to Anaerobic Respiration The chapter introduces anaerobic respiration, also known as cellular respiration without oxygen. It is emphasized that understanding anaerobic respiration necessitates prior knowledge of aerobic respiration, glycolysis, the Krebs cycle, electron transport chain, and mitochondria. The chapter suggests reviewing these concepts to fully grasp anaerobic respiration.
• 00:30 - 01:30: Anaerobic Conditions and Glycolysis The chapter discusses anaerobic conditions where mitochondria are absent and highlights the process of anaerobic respiration, primarily glycolysis followed by fermentation. It briefly outlines the steps of cellular respiration, starting with glycolysis where glucose is broken down into pyruvate. The energy yield from glycolysis is a net gain of 2 ATP.
• 01:30 - 02:30: Breaking Down Glucose in Cellular Respiration The chapter discusses the process of glucose breakdown during cellular respiration. It explains the journey of glucose once it enters the mitochondria, where it enters the Krebs cycle as Acetyl CoA. Carbon dioxide is released, and some ATP is produced. The chapter highlights that most of the energy is stored in NAD and FAD, which transport electrons through the electron transport chain. Ultimately, these electrons combine with oxygen to form water, resulting in the generation of a significant amount of ATP, totaling around 32-34 ATP, and netting approximately 38 ATP overall.
• 02:30 - 03:30: Disruptions in Cellular Respiration The chapter 'Disruptions in Cellular Respiration' discusses potential ways to disrupt the cellular respiration process. It points out that while the body usually has enough glucose, the process could still be disrupted if mitochondria are destroyed by a toxin or are inadequate in number, or if there is a lack of oxygen, which is crucial as it is the final electron acceptor in the electron transport chain.
• 03:30 - 04:30: The Role of NAD in Glycolysis The chapter discusses the role of NAD in glycolysis, highlighting its function as an electron acceptor. Without NAD, glycolysis would halt as it gets backed up. Anerobic respiration provides a solution in the absence of oxygen, enabling ATP production temporarily even when breathing is not possible. The process of glycolysis involves breaking down glucose into pyruvate, and the absence of oxygen rapidly leads to complications.
• 04:30 - 05:30: Solutions to Oxygen Deficiency: Fermentation In this chapter, the focus is on understanding the process of fermentation as a solution to oxygen deficiency in cellular respiration. It is explained how ATP is initially generated and then converted to NAD, which becomes NADH. When NAD is fully reduced to NADH, it cannot accept any more electrons, leading to a potential halt in ATP production if there is no oxygen or mitochondria present. The chapter discusses the challenges faced when there is no oxygen and presents fermentation as an alternative pathway to continue ATP production in such conditions.
• 05:30 - 08:00: Lactic Acid Fermentation Lactic acid fermentation and alcoholic fermentation are two evolutionary solutions for energy production. After glycolysis, animals and bacteria undergo lactic acid fermentation. For instance, in sloths, this process occurs due to their slow movement, while in humans, it occurs during intense activities like sprinting, and in bacteria, it helps in yogurt production. This process allows glycolysis to continue repeatedly, aiding in energy production.
• 08:00 - 10:00: Alcoholic Fermentation in Yeast The chapter titled 'Alcoholic Fermentation in Yeast' explains the process of alcoholic fermentation, where glucose undergoes glycolysis to produce pyruvate. In this process, the cells accumulate NADH, which cannot be utilized if the glycolysis path continues. Compared to lactic acid fermentation where pyruvate converts to lactate, alcoholic fermentation involves the conversion of pyruvate to ethyl alcohol (ethanol). This enables the continuation of glycolysis by regenerating NAD+, allowing yeast and similar organisms to produce energy without oxygen.
• 10:00 - 11:00: Conclusion: Importance of Anaerobic Respiration This chapter discusses the significance of anaerobic respiration, particularly in the process of ATP generation. It explains how electrons transferred from NADH can be converted into lactate, freeing up NAD+ to pick up more electrons. This cyclical process allows glycolysis to occur repeatedly, enabling continuous ATP production. Although it does not yield as much ATP as the full Krebs cycle and electron transport chain, it still produces a substantial amount of energy.

Anaerobic Respiration Transcription

• 00:00 - 00:30 [Music] hi it's Mr Anderson and in this video I'm going to talk about Anor robic cellular respiration or cellular respiration without oxygen to understand anerobic you must first understand aerobic respiration and so if these terms don't make sense to you glycolysis KB cycle electron transport chain and if you don't even know what a mitochondria is you may want to go watch one of my videos on that and I'll put a video link right up here um but what is Anor robic cellular respiration that's when we don't have oxygen or we don't have a
• 00:30 - 01:00 mitochondria present and so let's get rid of those and so what is Anor robic respiration it's really just glycolysis and then a new process called fermentation and so let's dig in a little bit deeper and so this is all the steps of cellular respiration remember we began with glucose in glycolysis we break that down into perate how much energy do we get from that we get two ATP now we put in some ATP but we net a total of 2 ATP
• 01:00 - 01:30 what happens to the perate it's going to go into the mitochondria it enters into the kreb cycle after it's converted to acetal COA we give off all that carbon as carbon dioxide and we make another two ATP and so we haven't released that much energy yet where' the energy go it's stored in NAD and fad they're going to transfer their electrons through the electron transport chain eventually those electrons go to oxygen with the formation of water and we're going to make most of our ATP here and so we're going to make somewhere between 32 and 34 ATP and so we net around 38 but
• 01:30 - 02:00 there's controversy it's probably not as much as that but how could we break this process well we could break this process number one if we didn't have any glucose but we usually have enough food inside our body but we could break this in two ways we could get rid of the mitochondria so if there was a toxin that destroyed the the mitochondria for example or if we just didn't have enough mitochondria present or if we didn't have oxygen remember Oxygen's right here at the end it's receiving those electrons It's the final electron
• 02:00 - 02:30 acceptor and if we don't have that the whole thing kind of backs up and so we're out of luck and we would be out of luck if it weren't for anerobic respiration if you want to feel what Anor robic respiration feels like just hold your breath for a while you're going to run out of oxygen you can't make ATP and you're going to get in some serious trouble very very quickly and so what is the problem why are you feeling that pain well it really boils down to glycolysis and so in glycolysis we're taking glucose and we're breaking it down into perate
• 02:30 - 03:00 remember we net 2 ATP where did that energy go it's being converted to NAD a lot of it is converted to NAD and so NAD is going to be reduced remember it's going to pick up electrons but pretty soon all of that NAD is full there's no electrons that can be donated it to it because it's now all at nadh or reduced nad+ and so that's where we get stock and where are we going to come up against this wall if we don't have oxygen or if we don't have mitochondria and so what is our solution to that well
• 03:00 - 03:30 through Evolution we've come up with two solutions to this we have lactic acid fermentation and we have alcoholic fermentation so first you have to do glycolysis but after that in animals and bacteria they do what's called lactic acid fermentation and so in a sloth they don't move that fast but maybe in you when you're sprinting or in bacteria when they're making yogurt they can do another process after glycolysis and what that does is allows us to keep doing glycolysis over and over again and
• 03:30 - 04:00 in alcoholic fermentation they do that uh by actually converting it to ethyl alcohol so let's go through those specifically again here's where we're stuck we've gone through glucose or glycolysis we've made perate but now we have all of this nadh and there's no way that we can keep going through glycolysis because all of it's filled and so in lactic acid fermentation what happens is this perate is converted further into lactate and sometimes you've maybe heard of that called lactic acid what happens with the formation of lactic acid well we're not making any
• 04:00 - 04:30 ATP but those electrons can now be converted from nadh and it can be transferred to lactate what does that do it frees up this NAD plus to go back and pick up more electrons again and so what we can do is through this process we can go through glycolysis over and over and over and over again and so we can make ATP every time we do that now we're not going to get all that ATP that we would if we went all the way through um kreb cycle electron transport chain but we can still make quite a bit of energy now
• 04:30 - 05:00 this is a picture over here of my son he is a CrossCountry skier and so in this picture right here he's on a treadmill he's skiing and this is a uh test to to calculate V2 Max to figure out how efficient you are at using oxygen but it also is going to measure your lactate threshold it's going to measure the amount of uh how much exercise you have to do before lactic acid builds up in your muscles in an appreciable amount and so if you are exercising really really quickly you get certain amount of
• 05:00 - 05:30 energy through um cellular respiration but if you go faster and faster and faster eventually your body will also add on top of that this lactate acid fermentation and if you've ever run for example a 400 meter dash or sprinted that pain you feel in your muscles is a buildup of this lactate in your muscles and So eventually that's not even enough and you're eventually going to just have to stop running or stop competing because it's too painful uh and that's that buildup inside your muscles and so what happens is is after you're done
• 05:30 - 06:00 then you have to go through and breathe a lot and then use oxygen and cellular respiration to break down that lactate but it does give us kind of like a turbo boost to go on top of that regular cellular respiration bacteria do the same thing uh if you were to put them in milk for example lacopa silus bacteria will go through lactic acid fermentation and that acid breaks down the proteins in the milk and makes yogurt and so that's one way that we can survive when we don't have oxygen lactic acid fermentation remember it still includes glycolysis but it's followed by this
• 06:00 - 06:30 lactic acid fermentation so we can go through that process again now we also see the same thing in alcoholic fermentation and so where would we see that that's going to be in things like yeast and so what are they doing they're breaking down glucose into perate but again they're stuck and so for example if we put a little bit of yeast and some grain and sugar in this bottle they're going to start to do cellular respiration just like we do but eventually they're going to run out of oxygen okay no oxygen can get in this container only gas can get out and So
• 06:30 - 07:00 eventually they're stuck and they would be stuck if they couldn't do fermentation what are they going to do they're going to convert that perate into ethyl alcohol that's that alcohol that we'd find in beer and wine now if you look at perate and ethyl alcohol we're missing a carbon here and the reason why is that that carbon's going to go towards carbon dioxide that's why we'd have a buildup of this carbon dioxide in beer or Champagne For example what is that doing though again it's the same thing it's picking up electron from
• 07:00 - 07:30 nadh and that's producing more of this nad+ and so we can go through that process of glycolysis over and over and over again and so we're looking at yeast inside here now they'll do alcoholic fermentation and they'll do that until they have consumed uh built up too much of this ethyl alcohol and then it'll eventually poison them and so we've known this for a long period of time and so fermentation has been going on for years and years and years the Egyptians used to make beer using fermentation um and we do it today as well and so what do you need all you do is put a little
• 07:30 - 08:00 bit of grain in there some sugar water and some yeast if you don't give them oxygen eventually they're going to convert to alcoholic fermentation and they'll do that until the level of alcohol inside there is going to kill the yeast they settle to the bottom and then we have alcohol and so that's Anor robic respiration what does it do it allows us to keep going if we have no oxygen or no mitochondria present it only lasts for a certain period of time and then we're out of luck uh and I hope that was helpful