How many cells does the human body have?
Many. It depends on the person dimensions.

Intro

The only way I can see to tackle this problem is “being” a physicist. First of all, this is a quite difficult question, it could take a whole scientific paper to make the right estimation, likely it already exist out there.

Method 1: weighting to know

The first way is comparing the weight of a person with the weight of a single cell:

##N=P/C##

Where: N- number of cell; P- person’s weight; C- cell’s typical weight.

Method 2: measuring to know

The second way is by calculating:

##N=P_V/C_V##

Where: N- number of cells; PV- person’s volume; CV- cell’s volume.

Final remarks

I leave the math to you. A third way is comparing the surfaces instead of volumes in method 2, thus you need to make the calculation for each organ. All these methods will give you an approximation, quite bad, but it is a good starting point.

Some calculationsCell weight[1]. ##3.5*10^-9## Assumptions . All cells are the same, e.g. bones, brain, hair… The majority of the body mass, say 90%, is compacted within cells.

Take a person of 70 Kg, therefore ##2*10^14## cells. Just to compare the world’s population is estimated as ##7*10^9##

Limitations. this calculation is for healthy people, some medical condition such as obesity may alter the cell natural properties such as weight. Further, we took as granted that all cells are the same, wrong! but useful.

There is a high probability that this number is smaller than the real value, just in the brain we have ##1*10^10## [2].

Cited references 1. Molecular Cell Biology. 4th edition. See http://www.ncbi.nlm.nih.gov/books/NBK21473/. Accessed on 09 02 2016. 2. List of animals by number of neurons. https://en.wikipedia.org/wiki/List_of_animals_by_number_of_neurons. Accessed on 09 02 2016.

Assignment: Cells in the Human Body

Assignment: Cells in the Human Body

You must proofread your paper. But do not strictly rely on your computer’s spell-checker and grammar-checker; failure to do so indicates a lack of effort on your part and you can expect your grade to suffer accordingly. Papers with numerous misspelled words and grammatical mistakes will be penalized. Read over your paper – in silence and then aloud – before handing it in and make corrections as necessary. Often it is advantageous to have a friend proofread your paper for obvious errors. Handwritten corrections are preferable to uncorrected mistakes.

Use a standard 10 to 12 point (10 to 12 characters per inch) typeface. Smaller or compressed type and papers with small margins or single-spacing are hard to read. It is better to let your essay run over the recommended number of pages than to try to compress it into fewer pages.

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The paper must be neatly formatted, double-spaced with a one-inch margin on the top, bottom, and sides of each page. When submitting hard copy, be sure to use white paper and print out using dark ink. If it is hard to read your essay, it will also be hard to follow your argument.

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Discussion Questions (DQ)

Initial responses to the DQ should address all components of the questions asked, include a minimum of one scholarly source, and be at least 250 words.
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I encourage you to incorporate the readings from the week (as applicable) into your responses.
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Your initial responses to the mandatory DQ do not count toward participation and are graded separately.
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I highly recommend using the APA Publication Manual, 6th edition.
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