English
Continue studying the present simple and present continuous verb tense by watching The Woolly Jumper.
Science
Here is the video Lia shared in class this week about the respiratory system.
When we breathe, why do we get only oxygen? What happens to the rest of gases?
Air is made up of roughly 20% oxygen, 78% Nitrogen, and the remaining 2% is
made up of carbon dioxide and other gasses in very small quantities.
When we inhale air, all the gases in it also enter our lungs. Externally, we have
no selective mechanism to inhale only oxygen.
In the alveoli, exchange of gases takes place. The haemoglobin in red
blood cells has an affinity for this oxygen present in the inhaled air and it is
immediately absorbed. The rest are sent out during exhalation.
The nitrogen does nothing in our bodies. Some of the other gasses can be
poisonous in large amounts - including carbon dioxide.
A mixture of oxygen and carbon dioxide would be poisonous. If there is too
much carbon dioxide in the mix, it blocks our ability to absorb oxygen and we
would lose consciousness quickly. If there is too much oxygen in the air it
can cause burning and damage to the tissues of the lungs, and we would still
die - quite slowly and painfully.
How do cells transform nutrients and oxygen into energy, waste and carbon dioxide?
Well, this is VERY complex. I’ll try to keep it simple. Cells use energy in the
form of a molecule called ATP (Adenosintriphosphate: C10H16N5O13P3):
So this is what cells need to build. To do so, cells make lots of chemical
reactions with glucose (C6H12O6) inside the cells.
The easy equation for this is: C6H12O6 + 6O2 → 6CO2 + 6H2O
Although it is more complex, since other molecules and enzymes are involved, as well as the ATP.
In any chemical reaction there is a transformation, but you still have the
same elements. For example, in this one, you have 6 C (carbon) atoms, 12 H
(hydrogen) atoms, and 6+12=18 O (oxygen) atoms at the beginning as well as at the end.
Click HERE for more information.
As always, please leave a comment about what you learned from watching these videos!
