OXIDATIVE PHOSPHORYLATION | Cellular Respiration

Summary

In this biology class video, Miss Angler dives into the intricate process of oxidative phosphorylation, the final stage of cellular respiration. She explains how hydrogens, harvested from glucose during glycolysis and the Krebs cycle, are used to generate ATP on the inner mitochondrial membrane with the help of cytochromes. The video illustrates the energy transfer process, likening it to a hydrogen molecule descending a staircase, ultimately combining with oxygen to form water. Viewers learn how this crucial cellular process results in the production of approximately 32 ATP molecules, essential for life's activities.

Takeaways

• 🔬 Cellular respiration involves glycolysis, the Krebs cycle, and oxidative phosphorylation to produce ATP.
• 📚 Glycolysis takes place in the cytosol and aims to access hydrogen atoms in glucose molecules.
• 🌀 The Krebs cycle occurs within the mitochondrial matrix to harvest hydrogens for energy.
• 🚀 Oxidative phosphorylation happens on the inner membrane of the mitochondria, utilizing hydrogens to produce ATP.
• 🏗️ The inner mitochondrial membrane contains phospholipids and cytochromes, which facilitate ATP synthesis.
• 🔋 Hydrogen electrons move through cytochromes, losing energy at each step, similar to descending a staircase.
• 🔄 NADH, an energy carrier from the Krebs cycle, delivers hydrogen to initiate ATP production.
• ⚡ The energy from hydrogen allows ADP to combine with a phosphate to form ATP, with each step representing a drop in energy level.
• 💧 Oxygen is the final electron acceptor, combining with hydrogen to produce water, a byproduct of cellular respiration.
• 🌟 The entire cellular respiration cycle results in the production of approximately 32 ATP molecules.
• 📈 ATP is the primary energy currency in cells, used for various life processes, while other molecules like NADH carry hydrogen for energy transfer.

Q & A

What is the main focus of the video script?

The main focus of the video script is on oxidative phosphorylation, a part of cellular respiration.

What are the prerequisites for understanding oxidative phosphorylation as mentioned in the script?

The prerequisites for understanding oxidative phosphorylation are watching the glycolysis video and the Krebs cycle video first.

What is the purpose of glycolysis in cellular respiration?

The purpose of glycolysis is to access the hydrogens found around a glucose molecule.

What is the role of the Krebs cycle in cellular respiration?

The Krebs cycle's role is to harvest hydrogens, which are the main energy carriers, from the products of glycolysis.

Where does oxidative phosphorylation take place within the cell?

Oxidative phosphorylation takes place on the inner membrane of the mitochondria.

What are the large protein channels embedded in the mitochondrial membrane called?

The large protein channels are called cytochromes.

How do cytochromes assist in ATP production?

Cytochromes assist in ATP production by passing along a hydrogen electron through the membrane, which facilitates the creation of ATP.

What is the role of NADH in the oxidative phosphorylation process?

NADH delivers hydrogen to the oxidative phosphorylation process, which is then used to create ATP.

How many ATP molecules are produced throughout the entire cellular respiration cycle?

Throughout the entire cellular respiration cycle, approximately 32 ATP molecules are produced.

What is the final hydrogen acceptor in the process of oxidative phosphorylation?

The final hydrogen acceptor in the process is oxygen, which combines with hydrogen to form water.

What is the significance of the cristae in the mitochondria?

The cristae are the folds inside the mitochondria that form the inner membrane, where oxidative phosphorylation takes place.

Outlines

00:00

🔬 Introduction to Oxidative Phosphorylation

This paragraph introduces the topic of oxidative phosphorylation, a key process in cellular respiration. The video aims to explain how ATP is produced during this stage, following glycolysis and the Krebs cycle. The importance of understanding the preceding steps is emphasized, and viewers are encouraged to watch related videos for a complete understanding. The setting for oxidative phosphorylation is the inner mitochondrial membrane, where the process involves large protein channels known as cytochromes that facilitate ATP production through a series of hydrogen electron transfers. The paragraph concludes with a brief mention of the structural components of the mitochondrial membrane, setting the stage for a deeper dive into the process.

05:00

🌟 The Mechanism of ATP Production in Oxidative Phosphorylation

The second paragraph delves into the detailed mechanism of ATP production during oxidative phosphorylation. It begins by illustrating the energy transfer process using a metaphorical staircase, representing the inner mitochondrial membrane's structure. The paragraph explains how ADP and phosphate combine to form ATP, utilizing the energy provided by hydrogen electrons as they pass through the cytochromes. This process is likened to a hydrogen molecule descending a staircase, with each step representing a decrease in energy level. The role of NADH as an energy carrier from the Krebs cycle is highlighted, and the paragraph describes how it delivers hydrogen to initiate ATP synthesis. The summary also touches on the final hydrogen acceptor, oxygen, which combines with hydrogen to produce water as a byproduct. The paragraph concludes by emphasizing the significance of the entire cellular respiration cycle in producing approximately 32 ATP molecules, which are essential for various life processes.

Keywords

💡Cellular Respiration

Cellular respiration is the process by which cells convert nutrients into energy in the form of ATP (adenosine triphosphate). It is central to the video's theme as it discusses the various stages of this process, including glycolysis, the Krebs cycle, and oxidative phosphorylation. The script mentions that the purpose of glycolysis is to access the hydrogens around a glucose molecule, which is a key step in cellular respiration.

💡Oxidative Phosphorylation

Oxidative phosphorylation is the final stage of cellular respiration where the hydrogens harvested from glucose are used to produce ATP. The video focuses on this stage, explaining how it occurs on the inner membrane of the mitochondria. The process is crucial as it is where the majority of ATP is generated, which is essential for various life processes.

💡Glycolysis

Glycolysis is the first step in cellular respiration where glucose is broken down into pyruvate, releasing energy and hydrogen atoms. The script refers to glycolysis as the starting point of the cellular respiration process, emphasizing its role in accessing hydrogens from glucose.

💡Krebs Cycle

The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions that further break down the products of glycolysis into carbon dioxide and more hydrogen atoms. The video script suggests that after glycolysis, the hydrogens are harvested in the Krebs cycle to be used in oxidative phosphorylation.

💡Hydrogen Carriers

Hydrogen carriers, such as NADH, are molecules that transport hydrogen atoms during cellular respiration. The script describes NADH as a 'wheelbarrow' that picks up hydrogen and delivers it to the oxidative phosphorylation phase, highlighting its role in energy transfer.

💡Mitochondria

Mitochondria are organelles found in eukaryotic cells that are responsible for producing energy through cellular respiration. The video script explains that the Krebs cycle takes place inside the matrix of the mitochondria, and oxidative phosphorylation occurs on its inner membrane.

💡Cristae

Cristae are the folds in the inner membrane of the mitochondria that increase the surface area for oxidative phosphorylation to occur. The script uses the metaphor of 'stairs' to represent cristae, illustrating how hydrogens 'jump' from one cytochrome to another in the process of ATP synthesis.

💡Cytochromes

Cytochromes are large protein channels embedded in the inner mitochondrial membrane that assist in the production of ATP during oxidative phosphorylation. The script describes cytochromes as 'tiny little factories' that help in sticking ADP and phosphate together to form ATP.

💡ATP (Adenosine Triphosphate)

ATP is the primary energy currency of the cell, and its synthesis is the ultimate goal of cellular respiration. The video script explains the process of ATP synthesis during oxidative phosphorylation, where ADP and a phosphate are fused with the help of hydrogen's energy to form ATP.

💡Phosphorylation

Phosphorylation is the process of adding a phosphate group to a molecule, in this case, converting ADP to ATP. The script describes phosphorylation as the step where energy is infused into ADP by the energy provided by hydrogen moving through the cytochromes.

💡Electron Transport Chain

The electron transport chain is a series of protein complexes in the inner mitochondrial membrane that transfer electrons from hydrogen carriers to oxygen, creating a proton gradient used to synthesize ATP. The script refers to the process as a 'game' where hydrogen electrons are passed along the cytochromes, which is part of the electron transport chain.

Highlights

Introduction to the topic of oxidative phosphorylation as part of cellular respiration.

Recommendation to watch previous videos on glycolysis and the Krebs cycle for a comprehensive understanding.

Explanation of glycolysis as the starting point for accessing hydrogens in a glucose molecule.

Description of the Krebs cycle's role in harvesting hydrogens as energy carriers.

The significance of hydrogens in providing energy for the final stage of cellular respiration.

Localization of oxidative phosphorylation to the inner membrane of the mitochondria.

Importance of understanding the mitochondrial membrane structure for grasping the process of oxidative phosphorylation.

Role of cytochromes as large protein channels in the mitochondrial membrane for ATP production.

Mechanism of ATP synthesis through the transfer of hydrogen electrons along the cytochromes.

Schematic representation of the 'staircase' model for the energy drop of hydrogens during ATP production.

NADH's function as a hydrogen carrier from the Krebs cycle to oxidative phosphorylation.

The process of ATP formation through the energy provided by hydrogens moving down the 'staircase'.

Final hydrogen acceptor role of oxygen in the production of water as a byproduct.

Overview of the entire cellular respiration cycle producing approximately 32 ATP molecules.

Terminology recap including cristae, cytochromes, energy carriers, and phosphorylation.

Conclusion emphasizing the importance of ATP for life processes requiring energy.

Invitation to like, subscribe, and turn on notifications for more educational content.

Transcripts

hi everybody and welcome back to miss

angler's biology class in today's video

we are going to be looking at cellular

respiration specifically oxidative

phosphorylation if you're new here don't

forget to subscribe turn on your

notifications because i upload every

thursday with a new topic

now in today's lesson we are going to be

specifically focusing on oxidative

phosphorylation so if you haven't gone

and watched the glycolysis video or the

krebs cycle first i suggest you go and

do that now

so picking up in our last lesson we were

looking at step-by-step processes moving

through glycolysis the krebs and then

oxidative phosphorylation i'm going to

remind you one more time of how this

goes so glycolysis is where we begin and

that is going to filter down into the

krebs cycle the purpose of glycolysis is

to access the hydrogens that we find

around a glucose molecule

after we have accessed those hydrogens

we're going to go into the krebs cycle

and the krebs cycle's purpose is to

harvest hydrogens hydrogens are our main

energy carriers and so we need to

harvest as many of them as possible

because they are going to provide the

necessary energy to finish the final

stage the stage we're doing today which

is oxidative phosphorylation this is the

stage where we are going to use these

hydrogens to produce atp molecules hence

the name of phosphorylation we are going

to add phosphorus

now before we get into the actual um

production of atp in our phosphorylation

step i need to make sure that everybody

knows where this is all taking place so

glycolysis if you remember from our

video takes place in the cytosol our

krebs cycle takes place inside the

matrix inside of the mitochondria itself

it's like the filling of the

mitochondria but where exactly does

oxidative phosphorylation take place it

takes place on the membrane of the

mitochondria now to remind you of the

structure the mitochondria has an outer

membrane and it has a inner membrane

this whole process takes place on the

inner membrane and it's important that

you familiarize the

structure of the membrane because i'm

going to be using it in my explanation

now in the membrane itself we have our

phospholipid layer which is all of these

yellow ball like structures and then

embedded in that layer are these very

very large protein channels

they are called cytochromes and

essentially they are going to assist in

the production of our

atp molecules and they do that by

essentially playing

a game where they're passing along a

hydrogen electron all the way along it

almost does this little jumping effect

where the hydrogen is going to jump from

the one and it jumps to the next and

then it jumps to the last at the very

end

if we were to zoom in on this as we see

here in our second picture we have our

cytochrome

and what we have is a hydrogen at the

top the hydrogen is providing the

necessary energy in order for us to make

the atp molecule and as you see as the

hydrogen moves through the cytochrome it

allows us to take an adp

fuse it with a phosphate and create atp

and water and this is what we call atp

synthesis but what i'm going to do is

i'm going to show you how to do this

step by step and how this actually works

now let's look at oxidative

phosphorylation now the diagram i'm

going to draw for you now is something

like a schematic drawing which basically

means that i'm not drawing a physical

model of what this really looks like i

am using a almost metaphorical image to

help me easily explain how this works

and so you'll see now i'm going to draw

like a flat of stairs that's not

physically what it looks like but

actually it has some similarity to how

the hydrogen jumps from one cytochrome

to the next i'm just going to use a very

simple diagram to explain this process

so in order to start phosphorylation we

need an important component from the

krebs cycle which was nadh it was the

hydrogen carrier

and along comes nadh and it delivers the

hydrogen

to this phase

that hydrogen we are going to use in

order for us to start the whole process

of creating atp

now once nad has done its job or if it

goes back to the krebs cycle and it is

going to collect another hydrogen and

it's going to do this over and over

again so we think of nad as a like a

wheelbarrow picking up hydrogen

now our

hydrogen atom or electron that we

technically have here

it is going to go through a process of

giving off its energy and the way in

which i'm going to draw that is with a

flight of stairs and i want you to

imagine every step that i draw a drop in

its energy level so our hydrogen is

going to start off at a high level of

energy and it's going to drop

it's going to go down drop

and it's going to go all the way down

i'm going to do it four times

right so this little staircase that i've

drawn here for you is technically a

representation of the inner membrane of

the mitochondria i want you to imagine

these being those folds right that we

have the cristae and you are going to

now follow along and see how this

hydrogen is going to provide energy in

order to make atp so first things first

we're going to need an adp and a

phosphate and so in order to join those

two together and essentially infuse

energy into it because that's what we're

doing we're infusing energy into it

adp and its phosphate comes along and it

swoops past

and the hydrogen provides enough energy

for the phosphate to join and create a

tp

and in doing so the effect on the

hydrogen is that it lowers its energy

level so you see it takes a step down

this process is going to happen again

along comes an adp molecule with a

phosphate

it's going to swoop past our hydrogen

which is in the membrane

and we're going to form a atp molecule

and the hydrogen then lowers itself to a

slightly lower energy level so it's gone

down a step

and it'll do it again along comes an adp

molecule diphosphate remember

and we join in

and we swoop

and we form a

atp molecule and yet again our hydrogen

has taken another step to a lower format

it does this one more time so we're

going to fill that in

and as it takes this final step and

makes this final piece of atp

we are left with a hydrogen molecule

that's actually quite low energy it sees

all the way down at the bottom of the

stairs

and so someone has to look after that

hydrogen because hydrogen doesn't like

to be on its own it actually has to be

looked after by someone or it needs to

be attached to somebody else and the

final hydrogen acceptor is oxygen

and so oxygen

which has been a part of this process

since the krebs cycle

oxygen is the final acceptor of the

hydrogen molecule so this hydrogen

molecule has been working really hard i

mean we accessed it in glycolysis we

harvested it in the krebs cycle and now

we're using it to make atp and so at the

very end of its journey it is going to

produce

the byproduct of water we're going to

stick that hydrogen and that oxygen

together to make water and that water is

the water vapor that you breathe out

along with the carbon dioxide that you

produce

so now as you can see at the end of this

process we have made many atp molecules

and that energy can go off and it can be

used for growth

movement

any of the life processes that require

energy

and so essentially that means that at

the end of our whole cellular

respiration cycle you make roughly 32

atp molecules now i know that you can't

see 32 over here

but it's 32 that are used and produced

throughout the whole cycle remember

we've looked at a very simplified

version of the whole krebs and oxidative

phosphorylation

as always i'd like to finish off our

lessons with a terminology recap so

let's start off by looking at what chris

day is cristae are the folds inside the

mitochondria remember the mitochondria

is where all of this cellular

respiration is taking place

and the cristae form the inner membrane

it's the folds should i say of the inner

membrane this is where oxidative

phosphorylation takes place and my

representation of that um in my drawing

was the little steps that i drew for you

now sitting inside of that inner

membrane are cytochromes cytochromes are

those proteins that are embedded in the

wall of that membrane and they assist in

the production of atp

basically there are tiny little

factories that are helping us stick

things together

now i spoke about energy carriers as

well and there are a few in these

examples one of them being the main

which one is atp it's the energy carrier

we're trying to produce but there are a

couple of other energy carriers like

nadh that are also considered energy

carriers because they're carrying around

hydrogen

and then we looked at phosphorylation

which is the process of adding a

phosphate so that is where we take an

adp molecule and we turn it into an atp

molecule that is phosphorylation

as always everybody i hope you've

enjoyed this video don't forget to like

subscribe and turn your notifications on

and i will see you again soon

bye