Sandbox DW1 009: Difference between revisions

||see section XIV.B.3 and XIV.B.7 - ''"When a marking violation is called, play does not stop. The violation must be corrected before the marker can resume the stall count with the number last uttered before the call minus one".''

{ Aristotle|Plato }

}}

===How do we get the oxygen we breathe?===

Oxygen is required by all aerobic animals as a basic mechanism to accept electrons and hydrogen ions produced during metabolism. Even when oxygen is all around us, in the air and in the water, oxygen need to be close to the cells where it's going to be used.

This is the time when blood comes into action. Blood is a specialized body fluid that delivers necessary substances to the body's cells – such as nutrients and oxygen – and transports waste products away from those same cells. Because oxygen is not very soluble in blood, animals have an efficient mechanism for capturing oxygen, transporting, and releasing it by the inner cells: hemoglobin.

{{Clear}}

===Hb, the mighty protein===

Hemoglobin (Hb), also spelled haemoglobin, (see on the right a three-dimensional representation of a single molecule) is the protein that carries oxygen from the lungs to the tissues where it's needed. The carbon dioxide produced by the consumption of oxygen. In order to function most efficiently, hemoglobin needs to bind to oxygen tightly in the oxygen-rich atmosphere of the lungs and be able to release oxygen rapidly in the relatively oxygen-poor environment of the tissues. It does this in a most elegant and intricately coordinated way. <u>The story of hemoglobin is the prototype example of the relationship between structure and function of a protein molecule</u>.  

<applet load='' size='300' frame='true' align='right' caption='' scene='User:Jaime_Prilusky/How_do_we_get_the_oxygen_we_breathe/1hho_bio/1'/>

=====The true colors=====

And now is when things get interesting. The hem group has the chemical and structural capabilities to capture an <scene name='User:Jaime_Prilusky/How_do_we_get_the_oxygen_we_breathe/O2/1'>oxygen</scene> molecule, which happens to be too close to the general shape of a molecule of <scene name='User:Jaime_Prilusky/How_do_we_get_the_oxygen_we_breathe/Co/1'>carbon monoxide</scene>, which binds hemoglobin about 240 times faster and better than oxygen, meaning that if both gases are available, hemoglobin will prefer CO over O2. ''THINK'': Can you imagine what will happen if by accident we breathe in a carbon monoxide rich atmosphere?

=====The whole molecule=====