Cellular Respiration – What Is The Function Of NADH And FADH2?

When you think of living cells and organisms, they all need FADH2 and NADH in order to survive and thrive properly.

Energy production is vital for any living thing to be able to do anything, so these naturally occurring enzymes are crucial for life on this planet.

Cellular Respiration - What Is The Function Of NADH And FADH2

Cells will use the coenzymes mentioned above for the process of cellular respiration, which is where food is turned into energy and fuel for the body to use.

What is the function of NADH and FADH2 when it comes to cellular respiration?

What exactly is cellular respiration? What are these co-enzymes?

All of these answers will be answered throughout the rest of our guide.

You might find the answers weren’t what you might have expected when you first found us!

A Bit Of Trivia

It doesn’t matter what type you’re thinking of, every cell has a mitochondrion present because it’s crucial for producing energy in the cell.

Not every cell only has one mitochondrion, however, with brain cells often having more than one in the same cell.

This is because they are used a lot for processing and use more energy than other cells in the body.

What Is NADH?

If you’re wondering what NADH is, rather than what it does, then we’ll explain it to you here.

NADH is basically the reduced form of NAD, which is correctly referred to as nicotinamide adenine dinucleotide.

This is basically a co-enzyme variation of vitamin B3, also known as niacin.

This can be found in all living cells, meaning it’s very common in the human body.

Including plants, you can expect to see this form of enzyme in most living things.

The oxidized form of niacin, also known as NAD+, gains a hydrogen ion and two electrons, which is seen in the form of H+ and 2e- respectively.

This is how an NADH molecule is formed! These reactions through reduction-oxidation, or redox, have a vital role to play in the generation of energy in cells.

What Is FADH2?

If you hadn’t worked out by now, FADH2 is actually very similar to NADH and is the reduced version of flavin adenine dinucleotide, which is simply known as FAD.

This is a form of FAD that is oxidized and has two hydrogen atoms, as well as two electron atoms.

This is how FADH2 is created. This conversion process also helps with energy production in cells, much like with NADH.

What Are The Functions Of NADH And FADH2?

When you look at the human body and the different roles that are played with energy production, FADH and NADH2 are crucial to keeping things ticking over.

Food that is eaten and consumed by the human body cannot be directly converted to energy without these co-emzymes working away.

Metabolism involves chemical reactions in order to turn food into energy to be used throughout the day.

This energy isn’t used all at once, however, with a lot of it being stored in adenisone triphosphate, or ATP for short.

This is a nucleotide and is also known as energy currency of the cell.

This ATP molecule is the biggest and most efficient storage unit for the energy being used in cells.

Almost like a big refrigerator, just without the coldness!

Cellular Respiration – NADH And FADH2

As we mentioned, ATP production plays a massive role in the process of cellular respiration, which is where food is converted into energy for the body to use.

As we spoke about earlier, NADH and FADH2 have a huge part in this process and help to ensure that the body doesn’t run out of ATP, producing more ATP to keep up with the energy conversion.

During the process of cellular respiration, NADH molecules are there to produce more ATP molecules, with the ATP molecules outnumbering the NADH 3 to 1!

Cellular Respiration - What Is The Function Of NADH And FADH2 (1)

On the other side of things, FADH2 products just 2 ATP molecules. When looking at this process objectively, you can see that it is more or less a process involving 4 main steps. 

These 4 steps include acetyl CoA formation, Krebs cycle, glycolysis, and electron transport chain.

The first, glycosis, is where sugar is used to generate pyrubate through breaking down.

Pyruvate is a molecule made of 3-carbon, and is converted into CoA, also known as acetyl coenzyme-A. 

The Krebs cycle is where CoA becomes oxidized and releases electrons that are high in energy, in the process.

These, along with hydrogen atoms are then combined with FAD and NAD+ to form FADH2 and NADH.

We have already highlighted the importance of these in the cellular respiration process and with converting food into energy and fuel.

The electron transport chain receives electrons from the FADH2 and NADH when they act as electron carriers.

These electrons that come from FADH2 and NADH are basically electrons with a lot of energy, which then leads to energy being released to make ATP, which is used for energy storage.

When it comes to the 4 stages of the cellular repsiration process, this is the final step.

The ATP is formed in the inner mitochondrial membrane.

Final Thoughts

That’s the end of our guide.

As you can clearly see, there is a massive amount of responsibility on the metaphorical shoulders of these co-enzymes and they need to be present for cellular respiration to take place.

At the end of the day, ingesting food is all well and good, however, you need to be able to convert it over to energy or it’s pointless.

We also mentioned how all of the energy isn’t used straight away because the body uses different quantities of energy at different times of the day.

For example, when someone is exercising or out and about, then they will need more energy conversion than if they’re asleep.

The four basic steps to the cellular respiration process include acetyl CoA formation, glycosis, the Krebs cycle, and the transport of electrons.

Jennifer Dawkins

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