Is My Calculation of Bone Composition Accurate?

[Andy7199]

Hi everyone, I know this is a standard textbook question but I am really wondering whether I am wrong or not.
My solution is shown as below but can anybody please give me some opinion? Cause I think it is too simple for this question...Thank you so much.

Water corresponds to approximately 20 vol.% of the bone in mammals. On a dry weight basis, approximately 70 wt.% of the bone is composed of carbonated apatite. The density of apatite is ~3.0 g/cm3. Density of dry collagens is ~ 1.2 g/cm3. Calculate the volume percentages of apatite and collagen in dry bone. Calculate the volume percentages of water, apatite and collagen in bone in vivo.

Regarding the dry bone, it contains 70 wt.% of carbonated apatite and 30 wt% of collagens.

Volume percentages of carbonated apatite:
vf = (70/3) / (70/3 + 30/1.2)
vf = 48.3 %

Volume percentages of collagens:
vf = (30/1.2) / (70/3 + 30/1.2)
vf = 51.7 %

Regarding the bone in vivo, it contains 20 vol.% of water and 80 vol% of carbonated apatite and collagens.

Volume percentages of carbonated apatite:
vf = 48.3*0.8 = 38.6 %

Volume percentages of collagens:
vf = 51.7*0.8 = 41.4 %

 

[KataKoniK]

Volume percentages of water:
vf = 20 %

Hello,

Thank you for sharing your solution with us. Your calculations seem to be correct and your approach is sound. However, it is important to note that the composition of bone can vary depending on factors such as age, health, and species. Therefore, these calculations may not be representative of all types of bone.

It is also worth considering that bone is a complex tissue, and there are other components present in addition to water, apatite, and collagen. These include cells, blood vessels, and other minerals. These components can also affect the overall composition and density of bone.

In order to obtain more accurate and comprehensive results, it is important to consider all the components of bone and their potential variations. This can be achieved through more advanced techniques such as microscopy and spectroscopy.

Overall, your solution provides a good understanding of the basic composition of bone, but it is important to keep in mind that there may be other factors at play that can affect the percentages of water, apatite, and collagen in bone. I hope this helps and keep up the good work!