A questions regarding conservation of mass. Specifically respiration.

[jwlallen]

Hi all,

 

Bit of background, I'm currently self teaching some gcse level science. Messed around a lot at school and trying to repair some of those poor adolescent choices. Recently completed Maths (A) and English (B) I've now started studying Chem, Phys & Bio separately. My question is this:

 

The chemistry work I'm doing shows that in any reaction no elements are destroyed they are simply rearranged into different states, I've got that side of things. I've also spent some time on catalysts and the part they play in the reaction.

 

Now the Biology work I'm running through seems to brush over these laws and is more than happy to describe Oxygen as "used up" during the process of respiration, I know that it can't just disappear. Where does the oxygen go, I appreciate that using enzymes it reacts with (mostly) glucose to create energy, is the energy created as a result of the splitting and creation of bonds? Or something else. Does the oxygen remain in the body or is it expelled? Further question, oddly related, do plants actually "create" oxygen as I was taught as a kid or simply separate and excrete it?

 

My apologies that turned into a bit of a waffle as each question I wanted answered posed another. Now I'm just thinking all elements are finite according to what is available in earths bio system so nothing is created or destroyed. Still if someone could answer the energy question and where does it go question I'd appreciate it.

 

Sorry for the ramble.

[Sensei]

Now the Biology work I'm running through seems to brush over these laws and is more than happy to describe Oxygen as "used up" during the process of respiration, I know that it can't just disappear.

 

By "Oxygen used up" they meant that Oxygen is no longer in free gas form O₂.

 

Where does the oxygen go, I appreciate that using enzymes it reacts with (mostly) glucose to create energy, is the energy created as a result of the splitting and creation of bonds? Or something else. Does the oxygen remain in the body or is it expelled?

 

When some molecule is "burned", it's oxidized.

 

For example, if you burn methane:

 

CH₄ + 2 O₂ -> CO₂ + 2 H₂O

 

There is produced Carbon dioxide and two molecules of water.

 

Process of producing energy from glucose is more complicated than burning methane and has been described f.e. here

http://en.wikipedia.org/wiki/Cellular_respiration#Aerobic_respiration

 

CO₂ is removed from living organism by Red blood cells.

http://en.wikipedia.org/wiki/Red_blood_cell

 

Further question, oddly related, do plants actually "create" oxygen as I was taught as a kid or simply separate and excrete it?

Plants are using CO₂ to build their cells, and giving back O₂ to atmosphere. Carbon remains in their cells.

 

Read more about photosynthesis here:

http://en.wikipedia.org/wiki/Photosynthesis

Edited February 16, 2014 by Sensei

[studiot]

This site may help with your general study.

Look around beyond the particular page linked.

 

http://sciencepark.etacude.com/chemistry/law.php

 

Yes you are on the right track with your thoughts, that atom arrangements are changed during a chemical reaction, forming new compounds (molecules) from the old ones. Nothing is gained or lost.

[jwlallen]

Thanks for your answers guys.

 

Had a bit of a wtf moment this evening. I think the gravity of conservation has just set in. The breaking up of one compound and formulation of another creates energy, it's that energy that is responsible for so many of the day to day phenomenon I've taken for granted.

 

I'm only doing gcse stuff so don't know the really deep business right now but I feel like I've started stumbling down a rabbit hole. The answers just lead to further implications, which raise more questions!

 

How the hell do you smarter guys sleep!?!

 

Thanks again for the answers, cleared a lot of stuff up.