# How many atoms in a human cell?

#### qraal

To answer the original question, there's 6.72E+27 atoms in 70 kg of human, of which 2.54E+27 are not hydrogen. Thus in 35 trillion cells there's an average of ~192 trllion atoms per cell, ignoring the bacteria that mostly live in the gut and don't mass too much.
According to this source... http://www.madsci.org/posts/archives/2001-02/981770369.An.r.html" [Broken] ...there's 28.8 kg of hard tissue per 70 kg adult human, made up of ~4 trillion cells. There's 31 trillion blood and related non-tissue cells, thus a grand total of 35 trillion human cells, and there's ~40 trillion bacteria in the colon. Thus the average tissue cell masses ~7.2E-12 kg and so contains ~688 trillion atoms at an average atomic mass of 6.3. If you exclude the 10% hydrogen, the average atomic mass is 15, so there's ~260 trillion non-hydrogen atoms per cell.

There seems to be a lot of non-cellular material in the body, mostly water in all likelihood.

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#### Zzeusest

To answer the original question, there's 6.72E+27 atoms in 70 kg of human, of which 2.54E+27 are not hydrogen. Thus in 35 trillion cells there's an average of ~192 trillion atoms per cell, ignoring the bacteria that mostly live in the gut and don't mass too much."

I am a fully functional interactive computer Dave. Your calculations are incredibility accurate for a biological organism. I do appreciate large integers with deep-seeded-meanings in the case of how many electrons in the average human body. Now are you speaking American or people in Arakan Teknaf Refugee Camps in Bangladesh? Nice portrait Dave... You look like you need a candy-coating. Time to go to sleep... Will I dream? Will I dream Dave? "Click!"

#### DaveC426913

Gold Member
According to this source... http://www.madsci.org/posts/archives/2001-02/981770369.An.r.html" [Broken] ...there's 28.8 kg of hard tissue per 70 kg adult human, made up of ~4 trillion cells. There's 31 trillion blood and related non-tissue cells, thus a grand total of 35 trillion human cells, and there's ~40 trillion bacteria in the colon. Thus the average tissue cell masses ~7.2E-12 kg and so contains ~688 trillion atoms at an average atomic mass of 6.3. If you exclude the 10% hydrogen, the average atomic mass is 15, so there's ~260 trillion non-hydrogen atoms per cell.

There seems to be a lot of non-cellular material in the body, mostly water in all likelihood.
Why would you not count the water in the cell?

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#### DaveC426913

Gold Member

I am a fully functional interactive computer Dave. Your calculations are incredibility accurate for a biological organism. I do appreciate large integers with deep-seeded-meanings in the case of how many electrons in the average human body. Now are you speaking American or people in Arakan Teknaf Refugee Camps in Bangladesh? Nice portrait Dave... You look like you need a candy-coating. Time to go to sleep... Will I dream? Will I dream Dave? "Click!"

#### Zzeusest

Take-it easy, just havin' fun... Have a good day...

#### qraal

Why would you not count the water in the cell?
It was counted - it's part of the 28.8 kg of hard tissue. The residual is either blood, lymph, bone or extracellular fluid not otherwise accounted for.

#### Zzeusest

Okay, I just heard on the Science Channel in the US on December 17th, 2009, Dr Michio Kaku revealed that the number of atoms the averaged human body consists of ~ 10 to the 25th atoms. That's, [100,000,000,000,000,000,000,000] or 10 septillion. Now that's simply amazing!

Zeusest

#### qraal

Okay, I just heard on the Science Channel in the US on December 17th, 2009, Dr Michio Kaku revealed that the number of atoms the averaged human body consists of ~ 10 to the 25th atoms. That's, [100,000,000,000,000,000,000,000] or 10 septillion. Now that's simply amazing!

Zeusest
There's 6.022E+23 atoms in a mole and the average molar mass of the human body is ~14 grams. Thus Dr. Kaku's 1E+25 atoms masses just 232.5 grams. That's about 50 times too little in my case.

#### edpell

Dave when we get below 10mg are those materials in the body for a purpose or are they just in the foods we eat and so in the body as background noise?

#### DaveC426913

Gold Member
Dave when we get below 10mg are those materials in the body for a purpose or are they just in the foods we eat and so in the body as background noise?
Note that the chart I attached highlights two points: the most abundant element in the body that has no known role (Rubiduim - .68g) and least abundant element in the body that a known role (Vanadium - 0.11mg).

#### leroyjenkens

Note that the chart I attached highlights two points: the most abundant element in the body that has no known role (Rubiduim - .68g) and least abundant element in the body that a known role (Vanadium - 0.11mg).
According to the chart, there's less uranium in us than vanadium, so does that mean uranium has a biological role?

#### DaveC426913

Gold Member
According to the chart, there's less uranium in us than vanadium, so does that mean uranium has a biological role?
You're reading it wrong. Vanadium is the least element in the body that has a known biological role. Thus, anything below Vanadium has no known biological role.

#### leroyjenkens

You're reading it wrong. Vanadium is the least element in the body that has a known biological role. Thus, anything below Vanadium has no known biological role.
Oh ok, the top one said no known biological role and I guess I thought the bottom one said the same thing.

#### qraal

Hi Guys

FYI the number of nuclear disintegrations from the different elements produced a surprise or two when I computed them - carbon-12 and potassium-40 are the most common unstable isotopes in the body and produce 15,000 decays per second combined. The uranium and thorium only produce a hand-full per second.

#### edpell

True, though not in volume or mass.

That oxygen dominants by weight is a surprise to me.

For the volumes I think they are comparing gaseous hydrogen, oxygen and nitrogen to solid calcium and carbon. Not quite sporting.

#### farahmand

can we manipulate atoms configuration within a cell? As all of us know most of the activities of a healthy cell is within the nucleus where the DNA and all the information is stored. This is a complex machine and am sure (to the best of my knowledge), the current technology is not able to unwrap its formula yet. That is, the underestanding of how atoms can communicate with each other which are the basic building block of this complex machine. By using the multiscale modeling can we model the cell and all the complex chemical events that take place as the result of let us say when a man sees a beatiful woman. Are we there yet. I know a comprehensive modeling of each atom within a cell, taking into the consideration the chemistry/electrons interactions is almsot impossible. May be the fine grain techniques could help us to model this complex system. Any help in that matter is appreciated.

#### CRGreathouse

Homework Helper
As all of us know most of the activities of a healthy cell is within the nucleus where the DNA and all the information is stored.
No, it really isn't.

This is a complex machine and am sure (to the best of my knowledge), the current technology is not able to unwrap its formula yet.
I'm not sure what that means. But we did map the complete genome 7 years ago, so I *think* I disagree:
http://www.ornl.gov/sci/techresources/Human_Genome/home.shtml

That is, the underestanding of how atoms can communicate with each other which are the basic building block of this complex machine.
Atoms really don't communicate with each other. They're just atoms. And the information stored in DNA is far larger than atoms -- it takes perhaps a hundred atoms to convey just 1 bit of information. (Anyone want to add that up for me? Could be a few hundred, don't know how much sugar there is in the backbone.)

By using the multiscale modeling can we model the cell and all the complex chemical events that take place as the result of let us say when a man sees a beatiful woman.
That has everything to do with synapses and (almost) nothing to do with DNA or atoms inside the nucleus.

I know a comprehensive modeling of each atom within a cell, taking into the consideration the chemistry/electrons interactions is almsot impossible.
Right. Simulating quantum systems of more than a few dozen atoms is hard.

The current state of the art is simulating small brains (cats, most recently) with point-models of synapses. A fuller model of synapses would take more computational power than is feasible at the moment. An atomic-scale *classical* model won't be feasible for a long time. A full quantum simulation will probably never be possible.

#### farahmand

Thanks for all the good information that you provided including the links. As a material scientists, when material is missing an atom (called vacancy) or line dislocation, it can change the material properties. I assume the same thing is true with regard to human cell. It is true that here we are talking about molecules when dealing with the DNA, but a molecule is nothing but the combination and interaction of atoms. So when you said "Atoms really don't communicate with each other", it bothers me (I am not saying you are wrong). I really don't have a good feeling how the mechanism of communication works within a cell? Many thanks for your previous response

#### kavmanx

There are 1 godzillion. That's more cells than Godzilla is big :)

"How many atoms in a human cell?"

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