(OLD VIDEO) Cellular Respiration and the Mighty Mitochondria

Summary

This video explains how cells generate ATP energy, a crucial process for all living organisms. The focus is on aerobic cellular respiration in eukaryotic cells, detailing the three steps: glycolysis, the Krebs cycle, and the electron transport chain. Each step plays a role in producing ATP, with oxygen being vital for maximum efficiency. The video also touches on fermentation, a backup process for ATP production without oxygen, and highlights the dangers of toxins like cyanide that disrupt this process. Mitochondrial disorders and the importance of research are also discussed.

Takeaways

• 🔔 Cells constantly need energy, and ATP (adenosine triphosphate) is crucial for this.
• 🧪 ATP has three phosphates, and breaking the bond of the third phosphate releases energy, turning it into ADP (adenosine diphosphate).
• 🌱 Photosynthesis makes glucose, and cellular respiration breaks it down to produce ATP energy.
• 🧬 Both prokaryotic and eukaryotic cells need to produce ATP, although their methods can differ.
• 💡 Aerobic cellular respiration is a highly efficient way to produce ATP in eukaryotic cells and involves the mitochondria.
• 🔄 The process of aerobic respiration includes glycolysis (2 ATP), the Krebs cycle (2 ATP), and the electron transport chain (up to 34 ATP).
• 🧬 Glycolysis occurs in the cytoplasm without oxygen and produces pyruvate, ATP, and NADH.
• 🔥 The Krebs cycle, which requires oxygen, produces ATP, NADH, FADH2, and carbon dioxide.
• ⚡ The electron transport chain uses electrons from NADH and FADH2 to power ATP synthase, creating a large amount of ATP.
• 🧫 In the absence of oxygen, cells can switch to fermentation, a less efficient method to produce ATP.

Q & A

What is ATP and why is it important for cells?

ATP stands for adenosine triphosphate, a type of nucleic acid that contains three phosphate groups. It is crucial for cells because it provides the energy needed to perform various cell processes.

How is ATP converted into energy?

ATP releases energy when the chemical bond holding the third phosphate group is broken, converting ATP into ADP (adenosine diphosphate). This energy is then used for cell functions.

What is the difference between photosynthesis and cellular respiration in terms of glucose?

In photosynthesis, glucose is produced as a product, while in cellular respiration, glucose is broken down as a reactant to produce ATP energy.

How do photosynthetic organisms benefit from both photosynthesis and cellular respiration?

Photosynthetic organisms can both produce glucose through photosynthesis and break it down via cellular respiration to create ATP energy, giving them an advantage in energy production.

What are the three major steps in cellular respiration?

The three major steps in cellular respiration are Glycolysis, the Krebs Cycle, and the Electron Transport Chain.

What happens during glycolysis?

In glycolysis, glucose is converted into pyruvate in the cytoplasm, producing a net yield of 2 ATP molecules and 2 NADH molecules. This process does not require oxygen.

What role does the Krebs Cycle play in cellular respiration?

In the Krebs Cycle, pyruvate is oxidized in the mitochondria, producing 2 ATP, 6 NADH, 2 FADH2 molecules, and carbon dioxide. This step requires oxygen.

How does the Electron Transport Chain produce ATP?

In the Electron Transport Chain, electrons from NADH and FADH2 are transferred through a series of carriers to create a proton gradient. This powers ATP synthase to generate ATP, with oxygen being the final electron acceptor.

What is fermentation and how is it different from aerobic respiration?

Fermentation is a process that occurs when there is no oxygen available. It is much less efficient than aerobic respiration, producing fewer ATP molecules.

How does cyanide affect ATP production?

Cyanide blocks a step in the Electron Transport Chain, preventing cells from producing ATP. This can be lethal because cells rely on ATP for energy.

Outlines

00:00

⚡ Introduction to Cellular Energy (ATP)

This paragraph introduces the concept of ATP (adenosine triphosphate) as a crucial source of energy for cells. It explains that cells are constantly working and cannot rest like humans, who may need time and coffee to gain energy. The section dives into the basics of ATP, describing how it releases energy by breaking the chemical bond of its third phosphate, converting it to ADP (adenosine diphosphate). The emphasis is on the importance of ATP for cellular processes, regardless of whether the cell is prokaryotic or eukaryotic.

05:13

🧬 Cellular Respiration and Mitochondria

This paragraph discusses how cells create ATP, focusing on eukaryotic cells and their use of aerobic cellular respiration, which takes place in the mitochondria. The chemical process of ATP production is introduced, starting with the formula for cellular respiration, which shares similarities with photosynthesis. The comparison highlights how photosynthesis produces glucose, while cellular respiration breaks it down to generate ATP. Photosynthetic organisms, like plants, benefit from both processes, while non-photosynthetic organisms must acquire glucose from food.

⚙️ Glycolysis: The First Step of Cellular Respiration

The first step of cellular respiration, glycolysis, is explained. This process occurs in the cytoplasm and does not require oxygen. Glucose is broken down into pyruvate, generating 2 ATP molecules and 2 NADH coenzymes, which are crucial for transferring electrons in later steps. The paragraph emphasizes that even glycolysis, a relatively simple process, requires ATP to initiate.

🌀 Krebs Cycle: The Citric Acid Cycle

This paragraph describes the second step of cellular respiration, the Krebs Cycle, also known as the Citric Acid Cycle, which occurs in the mitochondria and requires oxygen. Pyruvate is further broken down, releasing carbon dioxide and generating 2 ATP, 6 NADH, and 2 FADH2 molecules. These coenzymes will later contribute to electron transfer in the final step. The significance of these coenzymes in producing additional ATP is highlighted.

⚡ The Electron Transport Chain: ATP Production Powerhouse

The final step in cellular respiration, the electron transport chain, is presented as a highly efficient ATP production process occurring in the mitochondria. Oxygen is essential here, as it acts as the final electron acceptor, combining with protons to form water (H2O). The process involves transferring electrons from NADH and FADH2, creating a proton gradient that powers ATP synthase to produce ATP. This step generates the majority of ATP—up to 34 molecules in a 'perfect case' scenario, resulting in a total of 38 ATP from one glucose molecule.

🔋 Fermentation: ATP Without Oxygen

This paragraph explains that when oxygen is unavailable, cells can still produce ATP through fermentation. While far less efficient than aerobic respiration, fermentation allows cells to generate ATP in the absence of oxygen. The paragraph stresses the importance of ATP and provides a dramatic example of how a toxin like cyanide can disrupt the electron transport chain, preventing ATP production and causing deadly consequences.

🧪 Mitochondrial Disorders and ATP Research

The conclusion emphasizes the critical role of mitochondria in producing ATP and the life-threatening impact of mitochondrial disorders. There is a growing demand for research into these disorders, as they affect the cell's ability to generate ATP efficiently. The paragraph encourages curiosity and emphasizes the importance of understanding ATP production to address these medical challenges.

Keywords

💡ATP (Adenosine Triphosphate)

ATP is a type of nucleic acid that stores and provides energy for many cellular processes. The video explains that ATP is packed with three phosphate groups, and when one phosphate is broken off, a large amount of energy is released. This is crucial for cellular respiration, as ATP is the energy currency for cells, powering numerous biological activities.

💡ADP (Adenosine Diphosphate)

ADP is the molecule that remains after ATP loses one phosphate group, releasing energy. The video describes how ATP becomes ADP during energy production. Cells must continuously regenerate ATP from ADP to sustain their energy needs, and this cycle is essential for life processes.

💡Glycolysis

Glycolysis is the first step in cellular respiration, where glucose is broken down into pyruvate in the cytoplasm. This step does not require oxygen and yields 2 ATP molecules and 2 NADH molecules. In the video, glycolysis is presented as the initial phase of energy production, transforming glucose into a more usable form.

💡Krebs Cycle (Citric Acid Cycle)

The Krebs Cycle is the second stage of cellular respiration, taking place in the mitochondria and requiring oxygen. Pyruvate is further broken down, producing carbon dioxide, 2 ATP, 6 NADH, and 2 FADH2. This cycle plays a crucial role in energy production by oxidizing molecules and contributing to the electron transport chain.

💡Electron Transport Chain

This is the final and most ATP-efficient step in cellular respiration, occurring in the mitochondria. Electrons from NADH and FADH2 are transferred through carriers to create a proton gradient, which drives ATP production via ATP synthase. The video highlights this process as 'a beautiful thing' due to its effectiveness in generating large amounts of ATP.

💡Mitochondria

Mitochondria are membrane-bound organelles responsible for producing ATP through cellular respiration. The video emphasizes their importance, particularly in aerobic respiration, where they host the Krebs Cycle and electron transport chain. These organelles are referred to as 'a big deal' because of their central role in energy production.

💡Aerobic Cellular Respiration

This is the process by which cells produce ATP energy in the presence of oxygen. The video explains that this efficient process occurs in eukaryotic cells and involves glycolysis, the Krebs Cycle, and the electron transport chain. It contrasts with anaerobic processes, such as fermentation, which produce less ATP.

💡NADH

NADH is a coenzyme that transfers electrons during cellular respiration, aiding in ATP production. In the video, NADH is generated during glycolysis and the Krebs Cycle, and it plays a vital role in the electron transport chain, where it contributes to the proton gradient necessary for ATP synthesis.

💡Fermentation

Fermentation is an alternative method of producing ATP in the absence of oxygen. The video mentions that while fermentation is less efficient than aerobic respiration, it allows some cells to generate energy when oxygen is not available. This process is critical for organisms in low-oxygen environments.

💡Photosynthesis

Photosynthesis is the process by which photosynthetic organisms, like plants, create glucose from carbon dioxide and water using sunlight. The video compares photosynthesis to cellular respiration, showing how the former produces glucose, which is then broken down in cellular respiration to generate ATP. Organisms that perform photosynthesis have the advantage of creating their own glucose for energy production.

Highlights

Closed captioning is available, and instructions to turn it off are given.

Cells constantly perform processes that require energy, specifically ATP energy.

ATP (adenosine triphosphate) is a nucleic acid packed with three phosphates, and breaking the bond of the third phosphate releases energy.

When ATP releases energy, it converts into ADP (adenosine diphosphate) by losing one phosphate.

Cells, whether prokaryotic or eukaryotic, must produce ATP energy through different processes.

Aerobic cellular respiration is an efficient way to make ATP energy, especially in eukaryotic cells with mitochondria.

The reactants (inputs) of cellular respiration are glucose and oxygen, while the products (outputs) are ATP, carbon dioxide, and water.

Photosynthesis and cellular respiration share a similar formula, but the roles of glucose are reversed.

Photosynthetic organisms have the advantage of producing glucose through photosynthesis and breaking it down via cellular respiration.

Glycolysis, the first step of cellular respiration, occurs in the cytoplasm and produces 2 ATP and 2 NADH molecules.

The Krebs cycle (Citric Acid Cycle) occurs in the mitochondria, requires oxygen, and produces 2 ATP, 6 NADH, and 2 FADH2.

The electron transport chain, a key step in cellular respiration, produces the majority of ATP by transferring electrons and creating a proton gradient.

ATP synthase is the enzyme that adds a phosphate to ADP, producing ATP.

The net ATP production in cellular respiration can reach up to 38 ATP in ideal conditions.

Cells can perform fermentation to produce ATP in the absence of oxygen, though it's less efficient than aerobic respiration.

Cyanide is a deadly toxin because it blocks the electron transport chain, preventing ATP production.

Research on mitochondrial disorders is important as these disorders can be life-threatening due to the role of mitochondria in ATP production.

The Amoeba Sisters encourage curiosity and continuous learning about cell processes and energy production.

Transcripts

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Are you a morning person? One of us is and one if us is definitely not. Mainly because,

when I wake up in the morning, it just takes a while for me to feel like I get my energy

back. It takes a lot of time---and coffee---for that to happen for me.

Cells don’t really have that luxury. They are busy performing cell processes all the

time and many of the processes

that they do require energy. Specifically, ATP energy.

ATP stands for adenosine tri phosphate. It’s a type of nucleic acid actually, and it is

action packed with three phosphates. When the chemical bond that holds the third phosphate

is broken, it releases a great amount of energy. It also is converted into ADP, adenosine di

phosphate. And really, that’s just a fancy way of saying that it has two phosphates after

losing one.

So where am I going with this? Well, cells have to make this ATP energy. It doesn’t

really matter what kind of cell you are---prokaryote or eukaryote---you have to make ATP energy.

The process for making that ATP energy can be different, however, depending on the type

of cell. But you have to make ATP energy.

One way that this can be done efficiently is called aerobic cellular respiration. We

are going to focus on aerobic in eukaryote

cells which have many membrane bound organelles such as mitochondria. The mitochondria is

are going to be kind of a big deal in this.

So let’s get started. Remember we are trying to make ATP energy. Let’s take a look at

this formula. Remember that reactants (inputs) are on the left side of the arrow. And products

(outputs) are on the right side of the arrow.

This formula, by the way, looks remarkably similar to photosynthesis. Look how the reactants

and products just seem to be on different sides.

You know why? See, in photosynthesis, organisms (like plants and protists for example) made

glucose. Notice how glucose is a product. But in cellular respiration, we break the

glucose. Notice how glucose is a reactant. In order to make ATP energy.

So photosynthesis makes glucose---and cellular respiration, it breaks glucose. Kind of cool.

Photosynthetic organisms have the best of both worlds because they not only do photosynthesis

to make their glucose but they do cellular respiration to break it. I say that’s pretty

great, because glucose is the starter molecule in cellular respiration and needed in order

to get this going. If you aren’t photosynthetic, such as a human or an amoeba, you have to

find a food source to get your glucose. Cellular respiration involves three major steps. We

are going to assume that we are starting with one glucose molecule so that you can see what

is produced from one glucose molecule.

#1 Glycolysis- This step takes place in the cytoplasm, and this step does not require

oxygen. Glucose, the sugar from the formula, is converted into a more usable form called

pyruvate. It actually takes a little ATP energy itself to get this process started. The net

yield from this step is approximately 2 ATP molecules. And 2 NADH molecules. What is NADH?

NADH is a coenzyme, and it has the ability to transfer electrons, which will be very

useful in making even more ATP later on. We’ll get to that in a minute.

#2 Krebs Cycle-This is also called the Citric Acid Cycle. We are now involved in the mitochondria,

and this step requires oxygen. The pyruvate that was made is converted and will be oxidized.

CO2 (carbon dioxide) is produced. We produce

2 ATP, 6 NADH, and 2FADH2. FADH is also a coenzyme, like NADH, and it will also assist

in transferring electrons to make even more ATP.

#3 The electron transport chain. This is, just, a beautiful thing. Really. We’re still

in the mitochondria, and we do require oxygen for this step. This is a very complicated

process, and we are greatly simplifying it by saying that electrons are transferred from

the NADH and FADH2 to several electron carriers. They are used to create a proton gradient.

The protons are used to power an amazing enzyme called ATP synthase. Remember that the word synthase

means to “make” so that’s what ATP synthase does. All the time. It makes the ATP by adding

phosphates to ADP. Oxygen is the final acceptor of the electrons. When oxygen combines with

two protons, you get H20---aka

water. The electron transport chain produces a lot of ATP compared to the other two steps.

There isn’t an exact number on this---many textbooks will say 34 ATP. Meaning that the

net amount of ATP made when you add all the steps together is 38 ATP. But you need to

understand that this is a “perfect case” scenario and in general, you can expect a

lot less ATP made.

If we look at our formula again, we can see how the glucose and oxygen on the reactant

side was used to produce carbon dioxide (a waste product), water (a waste product), and

ATP energy. ATP energy was our goal.

Now, this was just one way of creating ATP energy---and a very efficient way at that.

But like we had said at the beginning, all cells have to make ATP energy. But the way

that they do it can differ. If there is no oxygen available, some cells have the ability

to perform a process known as fermentation. It is not nearly as efficient, but it can

still can make ATP when there isn’t oxygen.

We really can’t emphasize enough how important the process of making ATP energy is. If you

doubt how powerful it is, consider cyanide. This toxin is found in some rat poisons and

highly toxic. It works by blocking a step in the electron transport chain. Without being

able to continue the electron transport chain, cells cannot produce their ATP, and this poison

can be deadly in a very short timeframe.

There is also a demand for increased research on various mitochondrial disorders. Many mitochondrial

disorders can be deadly, because the role of the mitochondria in our body cells is so

essential for our ATP production. We are confident that the understanding of how to treat these

disorders will continue to improve as more people, like you, ask questions. Well that’s

it for the amoeba sisters and we remind you to stay curious.