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How many atoms in a human cell?

  1. Jun 4, 2006 #1
    How many atoms could fit inside a human cell?

    "A person's body is actually made up of trillions of cells (source: Science Concepts - Cells by Silverstein)", but how many atoms could fit inside a human cell?

    125 million atoms could fit inside the period at the end of this sentence. But how many atoms could fit inside a single (prokaryote, eukaryote, animal, human, or plant) cell?
     
    Last edited: Jun 4, 2006
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  3. Jun 4, 2006 #2

    Gokul43201

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    A typical human cheek cell has a volume of about 10-13m³. With some assumptions and approximations, I have 1016 atoms, give or take a couple of orders of magnitude.
     
  4. Jun 5, 2006 #3

    DaveC426913

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    "125 million atoms could fit inside the period at the end of this sentence."

    This seems conservative in the extreme.
     
  5. Jun 5, 2006 #4

    Pengwuino

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    Maybe he meant with room to spare :biggrin:
     
  6. Jun 5, 2006 #5

    Gokul43201

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    If you consider the period to be two dimensional, I'd imagine that estimate being conservative by only a couple or so orders of magnitude.
     
  7. Oct 3, 2009 #6
    125 million atoms in the period at the end of this sentence would seem accurate though all you would see off the computer screen would be light. So actually there would be no mass therefore no atoms(excluding the flowing electrons in the computer screen). Otherwise a palpable ink dot would most likely contain 125,000,000 atoms
     
  8. Oct 4, 2009 #7

    DaveC426913

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    How do you back this up?
     
  9. Oct 4, 2009 #8

    alxm

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    Re: How many atoms could fit inside a human cell?

    And most of the cells in the human body aren't human. Which is pretty indicative of the vast difference in size between human cells and bacterial ones. And there's a big difference between different human cells.

    E-Coli has 5.44 million base pairs in its DNA. Reckoning ~30 atoms per nucleotide, 125 million atoms wouldn't even cover half the atoms in its DNA.
     
  10. Oct 5, 2009 #9

    Andy Resnick

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    estimating the volume of a cell as 10 cubic microns, and a density 1.3 times that of water, gives 4.5*10^11 atoms/cell.

    A dot of ink, 1 micron thick and 0.5 mm in diameter has a volume of 7*10^5 cubic microns.
     
  11. Nov 2, 2009 #10
    Re: How many atoms could fit inside a human cell?

    On November 2, 2009, according to the National Geographic, "Each cell in the human body contains about 100 times as many atoms as there are stars in the Milky Way. As we all know, the Milky Way has ~ 200 Billion stars. SOOooo, 200,000,000,000 X 100 = 2.0 × 1013. Long story short, it's about, 200 trillion. Now, that's magnificent isn't it!

    Hold your horses my little stem cells, Science NetLinks, a resource for science teachers, stated that there are approximately "ten to the 14th power" (that's 100 trillion) cells in the human body. SOOOooo, 200 trillion atoms in 1 human cell X 100 trillion cells in the average human body = a whopping, 200 septillion. That's a 2 with 24 zeros following it! Are you conceptualizing this! We have 100 times more atoms in out body than stars in the universe! [Please see footnote "A"

    Let's not stop there shall we? How about 200 septillion atoms in the average human body X, as of November 2, 2009, the Earth's population is estimated by the United States Census Bureau to be, 6.794 billion = 13.588 X 10 34 ! GULP! I better go make breakfast. (:smile:)

    Zeusest
    The One and Only!
    Even if I have 2 Z's in my registration name. Oops...

    Footnote A The total number of stars in the universe is roughly 100 billion x 100 billion.

    That's 10,000,000,000,000,000,000,000 stars, 10 thousand, billion, billion. Properly known as 10 sextillion. And that's a very conservative estimate.
     
  12. Nov 2, 2009 #11
    Last edited: Nov 2, 2009
  13. Nov 2, 2009 #12
    Are there any authoritative sources for how much individual somatic cells mass?

    I've read that there's about ~10 trillion nucleated somatic & white-blood cells in an average adult, about 25 trillion denucleated red blood cells and about 40 trillion bacteria of all stripes.

    As humans - and most animals AFAIK - float, then the average density must be less than water. Most of the molecules in our bodies numbers-, if not mass-, wise are probably good old H2O, then there's the CHON that makes up most of the carbs, lipids and proteins in our bodies... so, elementally, we're probably mostly oxygen. If an average human masses ~75 kg & they're roughly 8/9ths oxygen, then we contain roughly 4200 moles of oxygen. About 2.52E+27 atoms of oxygen - and the 35 trillion human cells contain about 72 trillion oxygen atoms each.
     
  14. Nov 2, 2009 #13
    According to this source... http://web2.airmail.net/uthman/elements_of_body.html" [Broken] ...there's 43 kg of oxygen in a 70 kg human. So I should have said ~3/5 oxygen instead of ~8/9. Oh well. You can do all the figuring you like off the neat breakdown presented on the page. I suspected there was more oxygen because we're 70% water to start with and then oxygen is present in sugars/carbohydrates, bone, and other odds and ends. Oh well.
     
    Last edited by a moderator: May 4, 2017
  15. Nov 2, 2009 #14
    After throwing the data into a spread-sheet it's interesting to see how much hydrogen dominates in terms of numbers of atoms...

    hydrogen 62.2%
    oxygen 24.1%
    carbon 12%
    nitrogen 1.2%
    phosphorus 0.2%
    calcium 0.2%

    ...we're still mostly "star-stuff" especially if you count white-dwarf star-stuff ;-)
     
  16. Nov 2, 2009 #15

    DaveC426913

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    True, though not in volume or mass.

    daves-elements.jpg

    periodic-table.gif
     
  17. Nov 2, 2009 #16
    Pretty pics Dave! Where'd you find that periodic table template?
     
  18. Nov 2, 2009 #17

    DaveC426913

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    Thanks. I don't recall where I got the original PTotE. I just Googled until I found one that suited my purpose.
     
  19. Nov 2, 2009 #18

    lisab

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    Awesome, Dave :approve:.
     
  20. Nov 3, 2009 #19
    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.
     
  21. Nov 3, 2009 #20

    Danger

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    I know that I have at least 6 cells in my brain, because I have binocular vision and can see the 3 main colours with each eye. I assume that there are a couple of others that control my typing fingers. Beyond that, I haven't a clue.
     
  22. Nov 4, 2009 #21
    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.
     
    Last edited by a moderator: May 4, 2017
  23. Nov 5, 2009 #22
    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!"
     
  24. Nov 5, 2009 #23

    DaveC426913

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    Why would you not count the water in the cell?
     
    Last edited by a moderator: May 4, 2017
  25. Nov 5, 2009 #24

    DaveC426913

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    Wrong thread? Or wrong planet?
     
  26. Nov 16, 2009 #25
    Take-it easy, just havin' fun... Have a good day...
     
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